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PCB Making,Advice req' please

:: EPE Chat Zone :: Radio Bygones Message Board :: » EPE Forum Archives 2010 - » Archive through 29 April, 2012 » PCB Making,Advice req' please « Previous Next »

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rich13
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Post Number: 31
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Posted on Sunday, 26 February, 2012 - 11:31 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hello to all...

Ive been used to using the method of Press'n' Peel, but this is now proving exspensive to buy. Maplin now wants 18 for five sheets.
Online ive managed to buy from Ebay for five sheets just under ten pounds.
Ive now purchased both the resist spray and resist sheets, along with developer (already had the ferric chloride).
First i tried with the sheets, and along with a good guide via the web, made a small board.
I do have a UV lamp, but not bright enough,so relied on the kitched under unit strip light (flourescent) to do the job.
With transparent sheet and laser printer made the design. When the exsposure had finished i expected the parts that were to be resisted by light to be black, but i was in the opposite, i had copper, and the rest of the board the resist sheets. Using developer, my finished board was the complete board i strated out with, copper!

Ive tried the spray method just the once, where ive to spray board, in the oven (the wife loved that one!), but the lines of ecth wasnt dark enough. Im still playing but ide like a few pointers please.

Thanks

Rich
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chuckieboy
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Posted on Monday, 27 February, 2012 - 06:37 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Have a look here
http://www.megauk.com/producing_a_pcb.php
and here you can atcually watch a video on line
http://www.megauk.com/video.php

chuckieboy
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gordon
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Posted on Monday, 27 February, 2012 - 11:26 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi, I would consider building a UV exposure box, to get more consistant results. In the past I have used the spray resist method, but it is tricky to get the right thickness, and the coating free of dust particles. I have moved to pre-coated boards, and the quality/consistancy is very good. There are details here, among others, to build a UV box. http://www.electronics-lab.com/projects/mcu/018/index.html
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phonoplug
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Posted on Monday, 27 February, 2012 - 04:11 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I'm with Gordon on that one. I buy pre-sensitised sheets from CPC, only about a fiver for a large sheet, and get pretty good results with the UV box I have.

If the cost of a UV box is a bit much, you can buy spare 12" UV tubes and just put them into a caravan light or similar. Then just build it into a wooden box or something. There are a few different UV flourescent (type) tubes you can get. The completely clear ones are for erasing chips, so not sure how well they work for PCBs. The correct ones still have a white coating inside but I think its a lot thinner than a regular tube, and it gives out a purply light of course.
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rich13
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Posted on Monday, 27 February, 2012 - 10:29 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Thanks for all the advice.

Im going to take a look at the feeds you've given.
I did buy two small ready boards so ill go with that approach first. In the meantime, ive just purchased a 36wUV lamp box, cheap enough, (its actually for doing false nails), but it looks good enough for small boards. Ill wait until that arrives before i start. I watched a Youtube video last night which explained start to finish using the ready made board and then using the resist sheets, and a laminator, so this showed me ways also to improve.

I wont pound the thread with posts relating to this, but if a pcb does come out good, ill post back results.

Thanks again

Rich
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yorkie
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Posted on Friday, 02 March, 2012 - 10:41 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Well worth reading this thread, and in particular Joe's excellent exposure unit using UV LEDs:

http://www.chatzones.co.uk/discus/messages/7/13143.html

Good luck in your efforts!


David
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mikeb
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Posted on Saturday, 03 March, 2012 - 12:13 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I must put this topic on my website - it comes up every 5 months.

If you are getting into electronic, you really need an exposure box - unless you are rich and can send designs off to pcb manufactures. Dont forget if you are going to complex SMD designs, it can be difficult for my diy designs to meet very high dimensional specifications.

Anyway ...

1. Use pre-coated boards.
2. A laser/inkjet printer can be used to print onto transparancies. If the coating from your printer looks thin, print out two and 'prit-stick' then together.
3. I always use the very overpriced developer - one day I will buy some bleach and stop wasting money.
4. You need to make an investment for the exposure box.

A. If you are handy, then a 'replacement' tube and starter from Maplin will set you back 15. You need an inductance to start the tube of 4.7H about 170ohm in series with mains. This is applied to one of the pins at each end of the tube. I ratted mine from an old desk lamp.

The starter goes across the two remaing pins at each end of the tube (NOT THE SAME END or you will blow your heater). Look up a typical circuit diagram from the web and experiment on 'normal tubes', before you use your UV tube.

I have stuck foam to the bottom of my box and arranged for a sheet of glass to press down and lock in place. This will hold your board down.

I have just replaced my tube from Maplin after about 10 years of steady service.

B. You can buy from Rapid/Maplin at about 150.

rgds

mb
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mikeb
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Posted on Saturday, 03 March, 2012 - 12:22 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

... and you will need a 3 to 15 min. timer.

Watch your developer temperature - it should only be around 20C - that coolish - over temperature developer will simply strip off all the copper. I make my developer fro 1 egg cup of developer to 8 egg cups of 20C water.

Sometimes I wait for 5 minutes before the pattern starts to show - go slowly and gently.

Experiment with exposure times. I used up at least ten bits of board, before I got the hng of it.

Using the Maplin tube about 1 inch from my baord I they need about 10 min to work.

Post how you get on.

rgds

mb
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cjaysharp
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Posted on Saturday, 03 March, 2012 - 12:36 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I'm not sure you need to be rich to have PCBs manufactured any more, you just need patience. Some of the Chinese companies are ridiculously cheap and offer excellent quality with good turn round times.

I dug out all my PCB stuff last week then found that for the size of PCB I need I can get 8 double sided boards made and electrically tested for less than it would cost me to buy a bottle of FeCl from Maplin (which won't come close to filling my etch tank) Of course, I'll etch the PCB and drill it but it gave me serious food for thought.
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mikeb
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Posted on Saturday, 03 March, 2012 - 01:00 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@cj

... hmmm very interesting .... I have seen these companies advertising, but the prices were so low, I just thought it was a scam or at least trouble.
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rich13
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Posted on Saturday, 03 March, 2012 - 01:24 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@yorkie

Thanks for the web site, ill be heading there to seee whats on for offers

@mikeb

I did have time tonight to play with a small PCB, my daughter has just bought herself a unit that dries 'nails',(finger!) it has four 9watt UV tubes(36watt), and delivers 365um peak.Its the UV type thats u-shaped,the kind you find in fish pond UV pumps. It has a 120 second timer built in
(ebay item..190540905198)
Can you give any reason whay this would or not work.

Back to tonights PCB, after three hours i gave up, using ready made resist board, i put transparent image and exposed for twenty minutes, and nothing was apparent, so i had a go at spray resist, a small spray across the board, and then baked, transparent design across with sheet of glass ontop, exposure, after watching in between, again twenty minutes, this showed again nothing, so exposed again for another ten, at this point i lost the will to live, ive been into electronics since aged eight,(spark by trade) and used mainly strip board or bought from EPE PCB service. Its just now i want to do myself. The items youve listed i have, expect the exsposure box. I may get the tube you suggested and 'knock' one up into a box with timer, ive inductors ect in the shed, so it shouldnt be a problem.

As cjsharp pointed out, patience is the key, im not the best person for patience, but i dont like to give in and will persevere to the end.
Ill post back results if they do get better, and appreciate all the help.


@mikeb
Ive noted the ratio and temperatures ,as i wasnt to sure what it was, thank you


Its going to be a long weekend ..

Rich
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mikeb
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Posted on Saturday, 03 March, 2012 - 02:19 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

It is a fight to set yourself up, but once you have cracked it you will wonder what all the fuss was about and bash out a board without thinking.

Sorry - I cant really help on your question. I tried a load of lamps (and an old paper money checker) and none really worked. The Maplin tubes worked from the start. I have tried to get the frequency of the Maplin tubes but so far I cant find it.

There were some designs using LEDS and exposure in sunshine, but I was not convinced.


If a board is underexposed or exposed at the wrong frequency nothing will happen when you add developer. If your delevoper is too strong/hot you will see the pattern form, then vanish. It is difficult to overexpose, but if you have you will see your tracks 'necking'.

I tried the POSV 20 stuff and never got it to work. I suspect someting to do with the UV frequency. The can says it should be 350-450nm. The spray seems to attract dust all the way from Mars when I spray it. I gave up on the stuff ages ago.

I now think that Maplin sell TWO tubes and starters for 15.

As you are handy in this area, I would knock up a test rig with a shield for your eyes. After you have cracked it you can put the stuff in your own box. Dont forget you need a timer.

I will try to post a picture to give you some ideas.
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joe
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Posted on Saturday, 03 March, 2012 - 07:21 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Rich,

The pre-sensitised board is sensitive to UV light from aroud 340nm to 420nm. Not sure about the spray on resist you can buy but I would suspect it's sensitive to the same range.

Some UV Leds that are available put out UV at around 400 to 405 nm and to check that they would work, I built an exposure unit using them (as have many people) and they work fine.

http://www.hobbyelectronics.net/con_uv-exposure-unit.html

That said, I have a traditional tube based unit from Mega, that I modified by ripping out the terrible machanical timer, and replacing it with a home-brew digital one.

Rapid also do the replacement tubes 34-0707 for around 13+Vat that you can use as the basis of a home-brew design.

Joe
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cjaysharp
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Posted on Saturday, 03 March, 2012 - 08:34 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Rich, did you develop the board after exposing it or just look for the design on it?

I've had some pre-sensitised boards that showed hardly any difference after exposure and needed to be developed before you could see any tracks in the etch resist.

With fresh boards I have had success at exposure times of a couple of minutes, the older the board the longer the exposure required and to keep boards fresh they are best kept cold.

Mike, the PCB service I 'found' is ITEAD Studio, the service used by SparkFun. Cheap, reliable and good quality according to the reviews.
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yorkie
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Posted on Saturday, 03 March, 2012 - 09:29 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I've mentioned some of these points before, on my own experiences over the years, so I hope some repitition is in order.

When you expose the PCB you won't see any evidence that it has been correctly exposed - you only find that out when - as an act of faith and experimentation - you develop it. If the board is under-exposed, not all of the exposed areas will dissolve, and if you leave it any longer, all of the resist will then start to dissolve.

I don't use pre-sensitised PCB material - it's expensive and if you make a botch of it, all you are left with is plain PCB, which you can only make use of by spraying it yourself, which you could have done in the first place. The challenge with self-spray lacquer is finding a dust free atmosphere in which to spray, whigh is virtually impossible. I spray mine in the greenhouse, resting it on a piece of MDF, then immediately cover it with a plastic lunch box to prevent dust settling on it. (Make sure the surface on which it is placed is level or the lacquer will be thicker in one part than another). I leave it to dry for a few minutes, then take it indoors and put it in a desk drawer to harden off at least until the next day.

I don't find exposure times too critical - usually about five minutes in a 2 x 8 Watt tube exposure box. I always start off with a weak developer solution - I find that the recomended quantity of developer is far too concentrated and will strip the whole board in seconds. If it seems not to work, I add a few crystals till it starts to work. Usually a couple of minutes at most is all that's needed. I then dip the board in cold water to halt the process.

If you get it wrong and strip the whole board, all you need to do is clean it with meths, then re-spray the PCB, expose it again, then try it again in a weaker etchant solution. Its all a bit hit and miss some you win some you dont!

I steer well clear of Maplin's when sourcing PCB chemicals on the grounds of their high prices.

You can buy 1kG packs of lab grade SODIUM METASILICATE PENTAHYDRATE developer for 10.56 + 6.99 at this e-bay link:
http://cgi.ebay.co.uk/1Kg-Sodium-Metasilicate-Metso-Laboratory-Grade-/230315371046?pt=UK_BOI_Medical_Lab_Equipment_Lab_Supplies_ET&hash=item359fddaa26

I save the developer in a bottle to use again. It lasts a few weeks, but becomes so opaque that you cant see the PCB at the bottom of the container. I use a shallow plastic container about 30 cms long and 20cms wide so I can see the board through the developer, and rock the container gently back and forth. You start to see the dissolved lacquer floating off the surface which starts to happen after perhaps 30 seconds or so.

I stopped using ferric chloride as an etchant some years ago - it's ghastly messy stuff. Instead, I use sodium persulphate. You can buy a 500 gram HDPE bottle supplied as a fine crystalline white powder, which will make up to 2.5 litres of etching solution from the link below for 3.50+2.24 P&P. (The instructions for use are printed on the bottle label).

I find this to be a much cleaner and effective alternative to ferric chloride. It makes a clear liquid, which has a 6 8 minute etch time at 45C 50C. The bath life is a maximum of 4 6 weeks depending on use and operating temperature. As the PCB etches, the liquid turns light blue. You can use it several times over. I use an aquarium heater to warm it up, and an aquarium air stone about 4 long, with a small aquarium air pump, placed in the bottom of a plastic cereal container to bubble the solution to speed up the etching process, but you dont have to.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=270746775207&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

You can buy UV positive photo resist lacquer, tinning solution and other PCB materials from ESR Electronics, at Cullercoats who I find to be an excellent firm to deal with. The link to their PCB products is here:

http://www.esr.co.uk/electronics/products/frame_pcb.htm

A lot of experimentation is called for to get right what seems to work for you. Don't be discouraged - we're not putting rockets into space (well I'm not!) - we're just hobbyists!

(I don't have any connection with any of the suppliers mentioned above, or indeed, any commercial interest whatsoever, except as a customer).

Hope that helps a bit.

David
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phonoplug
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Posted on Saturday, 03 March, 2012 - 09:31 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

To add my 2p worth:

I use a ready-built exposure box got from Maplin years ago. It has 2x 12" tubes in it, probably set about 40mm back from the glass you press the PCB against. I expose the PCB for about 3m30s.

To develop I use caustic soda crystals dissolved in water, which can be bought from a chemist for a couple of quid for a tub that lasts far longer than I can remember. 1 teaspoon dissolved into about 1cm deep luke warm water in a 2 liter ice cream tub. Developing takes about 20 seconds while rocking the tub. ALWAYS rinse the board well between chemicals!

For etching I moved away from FeCl a long time ago so no brown stains everywhere and nasty smells. I use the clear stuff from Rapid and cannot recommend it enough:
http://www.rapidonline.com/Tools-Equipment/Clear-PCB-etchant-29448
This is the stuff used in industry for PCB making. Starts out clear then turns blue as soon as any copper is etched. Ends up deep blue when its about spent. Do shake the bottle you store it in before pouring into your tank as the stuff that settles is good not used sediment.

After etching I rinse and dry, then expose again for 5+ minutes before putting into the caustic soda again to remove the remaining resist off the tracks, leaving a shiny copper board. RINSE WELL.

Finally it goes into an immersion tin plating solution for anything between 5 and 30 minutes to finish it off. The tin crystals are from Rapid too. 15 for a litre's worth which last ages.
http://www.rapidonline.com/Tools-Equipment/Tin-plating-crystals-29475

Etchant goes back into a glass bottle, tin solution into the plastic bottle the crystals came in and developer down the drain as it was meant!
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istedman
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Posted on Saturday, 03 March, 2012 - 12:26 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Rich,

Have recently replaced the UV tubes in my light box. The old tubes were Sylvania Blacklight 350 8W tubes. From the part number they have a wavelength of 350nm. For best results prior to exposure I have to switch them on for 10 minutes to warm up prior to exposing a PCB.

Homebrew PCB making will take some trial and error before you get it right oh and loss of temper. :-)

Ian
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gordon
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Posted on Saturday, 03 March, 2012 - 02:26 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Someone else has tried the UV nail varnish curing unit for PCBs, and has been successful. http://yetanotherhackersblog.wordpress.com/2011/04/05/going-surface-mount/ You may have over exposed the UV resist, as the time quoted was about 100 seconds, so no image was visible, although it is normally quite faint to see. Looking at all the methods posted, the main variation seems to be how long the coated board is exposed to the UV light. In my case, I use 15 minutes with 2x8 watt tubes. In the past I have had a few boards that have just made it in the processing stages, but once you get the right exposure time, success is very high.
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rich13
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Posted on Saturday, 03 March, 2012 - 11:06 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Thank you to everyone, ive actually printed this page to refer for reference.

I tried again, im a grown man, and not ashamed to say i shed a tear, well, a tear of anger.
I tried again with the Photoresist Sheets, but this didnt prove very good results again.

The spray as MikeB mentioned atracts every dust particle in the universe , and baking in the oven ive now been banned (chicken was smelling like resist!)

@cjsharp
You are right, i didnt see any difference whatsoever, so i assumed it didnt work.
So im going to do a small test PCB tomorrow.

For the costs, its practical to make the unit at Joes site. Easy, affordable, and small.

All of you have various different methods, and each have given you results, so one(or a mix) of them has to work for me.

I was just about to post, then saw the page Gordon said about, seeing this im going to make more time to see if i can this unit to do the job.


Thanks again, appreciate the comments and help


Rich

(Message edited by rich13 on 03 March, 2012)
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mikeb
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Posted on Sunday, 04 March, 2012 - 01:17 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Also, those people into photography will know the old paper exposure trick.

Place a piece of thick card over your board and move it say 1/4 inch every 60 seconds. You will end up with a gradation of exposures from short to long.

Identify the strip that gives you good results - counting the strips from short to long will allow you to identify the the strip exposure time.

rgds

mb
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mikeb
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Posted on Sunday, 04 March, 2012 - 02:45 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

mr rig ..
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mikeb
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Posted on Sunday, 04 March, 2012 - 02:51 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

.. and my agitator ...
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mikeb
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Posted on Sunday, 04 March, 2012 - 02:56 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

...while I had my camera out ... my experimental double sided exposure unit ... it works!

I hope these give you some ideas.

rgds

mb
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cjaysharp
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Posted on Sunday, 04 March, 2012 - 03:21 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Ooh, nice kit and only vaguely deadly to the uninitiated :-)
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mikeb
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Posted on Sunday, 04 March, 2012 - 04:57 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@cj

Hahaha ... yeah .. a few 'elf and safety issues with my experiments ...
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younngjohnnie
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Posted on Sunday, 04 March, 2012 - 07:03 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

MikeB
What tubes are you using and what does the circuit look like to hook them up.
John
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rich13
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Posted on Sunday, 04 March, 2012 - 10:06 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi to all

Had some progress today, with a very small test, using the resist pcb, i made a pcb, at last.

But, it didnt come out that perfect, but trial and error, very faint, my problem is the the UV setup.
Ive decided to go and make Joes project, the UV Led's, rather than shell out loads of monies.

Very nice setup there Mike, (hope you use a RCD , hehe)

Rich
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mikeb
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Posted on Monday, 05 March, 2012 - 12:30 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@Yjonnie

They are either the Maplin or Rapid 'replacement'
tubes. They are marked Sylvania Blacklight 350 (I assume 350nm?).

I dont have a circuit drawing package. I will try to do something.

rgds

mb
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mikeb
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Posted on Monday, 05 March, 2012 - 12:33 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@rich

Yes I think your problem is the UV source, so you are now on the right track.
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younngjohnnie
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Posted on Monday, 05 March, 2012 - 11:46 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

MikeB
do they require a ballast in the circuit
John
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mikeb
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Posted on Monday, 05 March, 2012 - 02:19 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

John

The circuit is scribbled at the top right of the lid in my first picture if you can make it out.
Yes a ballast is needed - the ballast inductor is 4.7H at about 170ohm. I tried using the primary of some old 6.3V LT transformers, but they did not work.

The inductor is seen nearest the hinge - the other is just to supply some power to the timer.
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mikeb
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Posted on Monday, 05 March, 2012 - 02:47 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

John

My circuit - I hope it makes sense. Experiment with some cheaper 'normal' white tubes, before putting in your UV tubes.
application/octet-stream
Exposure box circuit 250V Mains.docx (33.5 k)
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mikeb
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Posted on Monday, 05 March, 2012 - 02:52 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

The diagram is a Microsoft Word document.
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younngjohnnie
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Posted on Monday, 05 March, 2012 - 04:21 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

thanks mikeb.
I have some old light fittings with ballast in them. I am going to experiment with them to see if will work - unless that is a bad idea
John
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mikeb
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Posted on Monday, 05 March, 2012 - 05:51 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Of couse be careful. If you have not experimented with open mains equipment before, or this is beyond your experience, then play safe and buy a unit - its not worth it.

As you can see, the circuit is trivial - its getting ahold of the ballast inductor (choke) thats tricky. I experimented with some transformers that had about the right resistance and 'looked big enough' and estimated it by eye.


Ensure your rig is secure to the bench - put a 1A fuse in the line in case things go wrong and use an old 8W lamp and never go near it when the mains is on.

A lamp across the mains is always a good way to remind you things are live.

I added a 50ohm 10W resistor in series with the fuse (with a switch to take it out of circuit if things looked ok) to act as a current limiter in case the inductance was a little too low. It will get darn hot when in circuit as predicted by Mr Ohm and Mr Watt.

Aslo try searching Ebay for Flourencent Ballast.
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mikeb
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Posted on Monday, 05 March, 2012 - 05:59 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

... or build Joes (low voltage) LED design as I think Rich is going to do.

rgds

mb
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dave_g
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Posted on Monday, 05 March, 2012 - 06:14 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Personally I'd go for the LED design every time, but if you want ballasts, just go to your local electrical wholesaler. Mind the price, though, trade prices can be very high and you won't get a discount unless you ask; haggle.

Mind you, wire wound is getting a bit rare these days, now it's almost banned. All to be high frequency electronic ballasts from now on.
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cjaysharp
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Posted on Monday, 05 March, 2012 - 09:39 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I bought ballasts and starter sockets from RS when I needed them, there's a good selection.
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rich13
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Hello

I went to the supplier that Joe mentioned for his UV Light Source Project., i decided to do a quick search beforehand, and found a considerable price difference for same produsct (spec below),

Im still going for the bigger option ,like MikeB setup as a friend in the field can get me some tubes in near future.


UV LEDS were from;

Item number 280834124496 (China)
100 UV LEDS @ £3.15 p&P Free- Bargain!!
(i ordered 200 greedy!)


Resistors were from;

Item number 260323928007 (UK)
50 x 56 Ohm 0.25w Carbon Resistors 1/4w Resistor 56R Price £0.99 + 89Pemce p&p

Adding just the quantity for the project,
100 UV + resistors, the matrix board cost me more at Maplin!!


If any one interested to build Joe's projects,its a bargain

I know its a lot longer ordering from China, but considering the prices, its worth it in my opinion.

UV LEDS Spec
Super Bright High Quality 5mm Purple/UV leds
* Emitted Colour : UV
* Size (mm) : 5mm
* Lens Colour : Water Clear
* Peak Wave Length (nm) : 395~410nm
* Forward Voltage (V) : 3.2 ~ 3.6V
* Reverse Current (uA) : <=30
* Luminous Intensity Typ Iv (mcd) :
Average in 2000
* Life Rating : 100,000 Hours
* Viewing Angle : 20 ~ 25 Degree
* Absolute Maximum Ratings (Ta=25°C)
* Max Power Dissipation : 80mw
* Max Continuous Forward Current : 30mA
* Max Peak Forward Current : 75mA
* Reverse Voltage : 5~6V
* Lead Soldering Temperature : 240°C (<5Sec)
* Operating Temperature Range : -25°C ~ +85°C
* Preservative Temperature Range : -30°C ~ +100°C


Hope it helps..


Rich
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mikeb
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Posted on Tuesday, 06 March, 2012 - 02:35 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@cj

Wow .. 6.20 for an 18W ballast .... thanks.

rgds

mb
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mikeb
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Posted on Thursday, 08 March, 2012 - 02:37 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Just a warning for those thinking of picking up the tubes from Rapid. I think they are 26mm diameter not 12mm.

rgds

mb
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joe
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Posted on Thursday, 08 March, 2012 - 02:51 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Rapid Part number: 34-0707 (and I've got a box sat in front of me) 2 x tubes, 2 x starters

Tubes are made by Sylvania
300mm Long, 8W, 16mm dia

No additional part numbering on the package.

Regards,
Joe
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mikeb
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Posted on Thursday, 08 March, 2012 - 03:26 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

oops .... got that wrong .....
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rich13
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Posted on Wednesday, 28 March, 2012 - 09:42 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi all

Its been a while, but ive made the UV setup today, its not a very eleborate design, just a quick knock up of what i had around. But, its safe and works. Until im happy with results, ill make it more neater and add another tube.

Ordered the 15w tube, and i had already some fish tank light ballast units, which were perfect for the job.

Done a very small test PCB, and this came out good, but, i think as youve already mentioned playing with exposure times. Using the pre-coated board, i didnt see any changes as Cj' said, until i put into the developer, but the design soon dissapeared, so ive to get the exposure right before i get this correct.
I started to make Joe's UV LED board,ive made a third of the board,the result i got using just this amount of the LEDS was amazing, cant wait to see result with all the led on the board!.
To end, has anyone a circuit diagram for a 3-15 minute timer.

Thanks for all the help

Rich
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arw
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Posted on Wednesday, 28 March, 2012 - 10:50 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

You could try my old Mains Delay Switch, and I will be revisiting my UV Exposure Timer project and uploading that too in due course.

http://alanwinstanley.com/storage/pdfs/mains%20delay%20switch.pdf

and the original prototype (1978) revisited
http://alanwinstanley.com/storage/pdfs/Mains%20Delay%20Switch%20prototype.pdf

Just rejig the RC for the delay you want. The main benefit is that it helps get consistent results.

A much improved version was done in the mid 1990s. I'll dig it out in due course.

-- Alan W
Alan W -- EPE

More online resources at www.epemag.net
Personal site www.alanwinstanley.com
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rich13
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Posted on Thursday, 29 March, 2012 - 01:06 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Thanks Alan for the Timer details. Its a nice and easy setup, so is ideal. If you do find the 1990 version, i would like to see it.


Thanks again
__ Rich __
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cjaysharp
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Posted on Thursday, 29 March, 2012 - 08:18 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Rich, I think you need to look more at the concentration and temperature of your developer than exposure time.

If you think about it you expose and strip the stuff you don't want to stay so if the board is under-exposed and the developer is right then none of the etch resist will go (or take far too long and be patchy). The developer will, if too strong or hot (or both), strip the entire board.
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cjaysharp
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Posted on Thursday, 29 March, 2012 - 08:26 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Alan, a quick look at the delay switch, a rough guesstimate excluding case and sockets I reckon it'd still be around 7-8 to build, how's that for longevity :-)
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arw
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Posted on Thursday, 29 March, 2012 - 10:13 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

My UV Exposure Timer was part of my series about Making your own PCBs, ~ May 1992 which I will fish out.

What surprised me at the time was the extra mains filtering needed to stop the fluorescent lights from e.g. re-triggering the timer. I added a seperate delta-cap filter which did the trick.

I think I did a 12V pcb drill control unit as well in the 80's which I'll find and write up eventually. The prototype was scrapped though.

Happy times :-)
Alan W -- EPE

More online resources at www.epemag.net
Personal site www.alanwinstanley.com
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rich13
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Posted on Friday, 30 March, 2012 - 09:35 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

CJ , thanks for the advice , developer is/was at room temp (18-22degrees give and take), and as per instructions, 10g per 100ml water.
This could be to strong?!, if so then a bit of experiment to find correct ratio. Plusthe time of exposure as you mentioned.

In the meantime, some bad news, and im ashamed to say this. My last post i said i quickly made the UV board up, for test purposes. Well in the process as i had no lid defeat switch, i exposed my eyes to long, which resulted in being down at A&E at 4am Thursday, pitted both eye lense. I should of known better, but i was being to much of an idiot in doing the project quickly, a good lesson for the peeps starting out in PCB/electronics, to wear eye protection, and take the time to do the job first time right. Took ages writing this with just one eye. I think the seller of these tubes should hand out a warning notice to those who have no idea in the first place what UV or these tubes can do.

Thanks for the help everyone, as i know ill get this correct one day
__ Rich __
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arw
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Posted on Friday, 30 March, 2012 - 10:23 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Oh dear, that's pretty bad news. I have an LED torch using UV led's and must admit my eyes feel sore after a short time. :-(

Do not stare into laser with one remaining eye!
Alan W -- EPE

More online resources at www.epemag.net
Personal site www.alanwinstanley.com
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rich13
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Posted on Sunday, 01 April, 2012 - 11:20 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Sorry to yet again bore you, but ive done the pcb earlier, and as CJ correctly said, developer was the problem, found the approx solution by adding water, exposure i used at the end was 4 minutes, then after developing re-exposed for 2 minutes, then etched.Using pre UV-Resist board, i think for a first time effort this was reasonable, any thoughts?. All the messing about and losing eyes for two days was worth it..

@Alan, if you manage to find the 1992 edition relating to your PCB article, i would be gratefull.

Thanks again for putting up with me
__ Rich __
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rich13
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Posted on Sunday, 01 April, 2012 - 11:30 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Sorry forgot to attach image...

pcb
__ Rich __
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gizo
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Posted on Monday, 02 April, 2012 - 12:30 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

"then after developing re-exposed for 2 minutes"
Did you just put the board back under the UV after developing?
That sounds unusual.
Where did you get the idea from. Is it recommended somewhere?
You would think that if it was underexposed then the developer would have attacked it already, and so it ought to be OK to go ahead and use the etcher solution on it without further UV.

Glad your eyes came out OK ... underexposure is sometimes a good thing :-)
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rich13
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Posted on Monday, 02 April, 2012 - 01:23 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@gizo
reading countless articles, i basically extracted various ideas and then ran with them.

To sum up how i did mine was
expose image, wash with developer, then as one article said , to re expose for 2 minutes, then developer, then etch. (last post i said i etched , but it was late, so tomorrow is the etching)

Now that you have mentioned abour re-exposing, its obvious thats not what needed ,so i will steer clear of that step.
As the members have been doing home pcb themselves for many years, im taking their advice. One part i was doing, was tring to get the developer to the point where is would start at once removing the resist. But, after reading Yorkies post again, ill rely more on a weaker solution, and add as appropiate.



Thanks for your input
__ Rich __
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terrym
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Posted on Monday, 02 April, 2012 - 02:01 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

The strength of the developer I uses (Potassium Carbonate), is a large teaspoon per Litre of water. (That's approx 8grams) Warmed to 50deg C.

Your pic looks pretty good, so you are just about there as far as your process goes.

TM
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rich13
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Posted on Monday, 02 April, 2012 - 02:18 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@terrym

Can i buy Potassium Carbonate at a chemist ? or is it online purchase.

Thanks
__ Rich __
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terrym
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Posted on Monday, 02 April, 2012 - 04:08 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

First, you need to make sure it is compatible with what ever you are using for the resist. Check your current developer to see what it is.

Not being in the UK, I couldn't say if you can get it at a chemist.
I buy mine in bulk from a chemical supply company. Apparently, it is also used in fruit drying, so should be readily available.

TM
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yorkie
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Posted on Monday, 02 April, 2012 - 08:52 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I use sodium metasilicate pentahydrate, ('Metso') which is widely available cheaply on internet - typically under 10.00GBP per kG, or much more costly from UK electronics suppliers including 'the usual suspects'. As with all developers, the concentration is quite critical -in my experience it needs to be much less concentrated than the instructions suggest. Best to first try it on an unexposed piece of board to make sure that it won't strip the unexposed UV lacquer off because if it does, then clearly the whole board would be stripped whatever the exposure time. You can always add a little developer at a time to get the right concentration if it seems to weak.

Generally, I've found the exposure time to not be too critical,and it's best to first find out by test pieces what the minimum time is. I don't see how we could 'over-expose' a board unless of course the tracks on the mask aren't totally opaque and will allow some UV to get through on a longer than necessary exposure. I self-spray the lacquer rather than to buy it pre-coated because if I have failures (and I do), I can always clean off the board with meths and re-spray it. I use a two x 8 Watt tube home-made box, and use a 5 - 7 minute exposure time.

I store the developer in a plastic bottle for use again. It will make many boards before it becomes exhausted, and before it reaches that stage it becomes too discoloured to be able to see the PCB as it develops. I use a largish plastic tray (actually a cat litter tray about 12" long x 10" wide) as a developer tray because the developer then only needs to be about 1" deep, so you can see progress with the board as you rock the tray back and forth.

Here's a link to just one of many suppliers of 'Metso' developer:

http://www.ebay.co.uk/itm/1kg-Sodium-metasilicate-pentahydrate-High-quality-/140667072644?pt=UK_BOI_Medical_Lab_Equipment_Lab_Supplies_ET&hash=item20c0693084

Hope that helps a bit.

As a footnote, I have to say that apart from the challenge and satisfaction of 'home-brewing' your own custom designed boards, where boards are available for magazine projects, such as in EPE, it makes little economic sense to make one's own - even less so when a kit is avaiable. I've just made a digital capacitor meter from a kit which had a very high quality plated through hole double-sided screen-printed PCB, the digital display, pic and all other on-board components, which cost less than 15.00 GBP inc P&P. Great little project - it would make little sense to try to emulate that, and you still have the enjoyment of building it and boxing it up to your own requirements.


Best of luck!

David
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cjaysharp
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Posted on Monday, 02 April, 2012 - 08:53 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Rich, brilliant, that board looks fine to me :-)

Now you've got the chemistry working for you you can experiment with the exposure times.

Shorter exposure times are better (as long as the board is exposed) and will give a more defined image when you develop because you can get 'undercutting' of the layout from parallax errors and light leakage through the ink/toner so the shorter the time it's exposed for...

Try and arrange it so the printed side of your transparency is in contact with the board, that way there's less light 'leaking' under the image and you'll find the images are even sharper which will make it possible to produce even finer pitch boards if you need to.

As Gizo says, the re-exposure isn't necessary after the initial developing stage, I used to re-expose boards after etching and drilling then into the developer again to remove the etch resist but even that's not necessary.

If you're going to drill and solder it immediately you can remove the resist with acetone (nick the wife's nail polish remover if you dare) and then wipe over with Isopropyl alcohol, if you're not going to solder it immediately and aren't tin plating the board then leave the resist in place, it stops the copper tarnishing which saves you having to clean the board with an abrasive pad or rubber.

Once again, well done and I hope your eyes are recovering well.
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zeitghost
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Posted on Monday, 02 April, 2012 - 10:24 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Arc eye is nasty & best avoided, as I think you've discovered.

The last pcb I made I used 10 mililitres of MEGA developer diluted about 25 to 1 with warmish water.

Did the job beautifully.

Exposure was about 2 minutes (though it seemed longer) with a 4 tube exposure box.

Medium was toner on tracing paper (60gsm) from Rapid Electronics.

Board was from Rapid Electronics, single sided non glassfibre, Fotoboard 2.
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gordon
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Posted on Monday, 02 April, 2012 - 04:07 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi Rich, That board looks pretty good. Was it a Maplin ready coated board?, I have only seen brown resist on their boards. There are a few choices in the developer, but as already mentioned the strength is important. My preference is to use sodium hydroxide. Readily available and cheap. Usual concentration is 7 or 14 grams per litre, depending on the type of resist.
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yorkie
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Posted on Monday, 02 April, 2012 - 05:42 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I've heard it said that if you use sodium hydroxide (AKA 'lye' & 'caustic soda'), as a general rule (rule thumb - no pun intended!) if you start off with a very weak solution of just a few grammes per Litre, and rub your finger and thumb together in the liquid, when it reaches the right concentration, it should feel 'soapy'. I never managed to get the concentration right myself. I guess we all end up using whatever techniques and 'modus operandi' we each find works for us.

I don't wish to preach health and safety to adults, but it goes without saying that caustic soda is very nasty stuff and should be treated with respect and the usual precautions when using and storing it. Industrially it's used in paper making electroplating and the production of cellophane. Domestically, it's widely available in the UK as a drain cleaner. (white crystals). You should never add water to chemicals - only ever add chemicals to water.

David
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arw
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Posted on Monday, 02 April, 2012 - 06:30 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I always used caustic soda, a small scoop (say 20 ml) in a litre of warm water made a good developer. I would just add a bit more if it wasn't working.

I also discovered that your skin turns green and dies if it's splashed with caustic soda...

I wonder if an electrolytic answer would be to develop boards in salt water and apply a potential, which produces caustic soda (see the thread on coin cell dangers).

Problem I have with DIY spraying your own resist is that the lacquer puddles out at the edges and tends not to develop away cos it's thicker there. So I'd use a dab of acetone (nail varnish remover) on a cotton bud to strip away any unwanted resist.

@ Rich yes I'll dig out that article as soon as I can. Maybe the whole PCB article as well, but it was based on creating manual artwork on film using dry transfers, crepe tape and is less relevant today I guess.

-- Alan W
Alan W -- EPE

More online resources at www.epemag.net
Personal site www.alanwinstanley.com
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rich13
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Posted on Monday, 02 April, 2012 - 10:40 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@cjay, eyes are good now thanks. Lesson learned
pity, i can see the missus again!.

You say about putting the printed side down to cut down on light leakage. Ive a feeling thats where i went wrong with this project. After etching tonite, i had a lot of 'bleed', tracks touching other tracks, anda few breaks here and there. The etching went fine, just this was the problem.

@gordon
yes m8, that board was from maplin, brown resist. At this present time im sourcing on the web/ebay, I hate Maplins prices.

As the caustic soda has good outcome, im going to purchase tomorrow, and try once again. Im going to have nightmares of pcb's.

Alan, thank you, appreicated.

Again, thanks to all
__ Rich __
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cjaysharp
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Posted on Tuesday, 03 April, 2012 - 08:52 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

The 'bleed' tracks could be a result of dodgy resist coating, uneven copper cladding or a bad transparency (or any combination of the above), the bits that stay are the bits that weren't exposed to UV so you should be able to see them in the resist after developing.

If you can see whiskers of resist after developing then there's no problem with using a craft knife to remove the obvious ones before you etch, it's not as if you can damage the copper that's going to be etched away..
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yorkie
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Posted on Tuesday, 03 April, 2012 - 09:12 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Surely the printed side of the acetate should be face up - adjacent to the board, so there is no gap between the board and the artwork, so that UV can't creep behind the tranparent thickness of the acetate between the glass and the PCB at the edge of all the tracks? That's how I've always understood it. Of course, which ever way round the acetate is, we must make sure that we don't end up with a mirror image of what we really wanted. The next person to do that won't be the first, or the last! (Easy enough to 'flip' the artwork in Photoshop or whatever).

David
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hackinblack
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Posted on Tuesday, 03 April, 2012 - 10:12 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

here is a good description of an alternative to the expense of photo resist,
a twist on the toner transfer method
http://www.users.senet.com.au/~astrohog/EasyDIYpcb/
i noticed that mouser.eu (the only online shop available here in France with an english language site
that is actually useable(get the hint Farnell,RS et al..)doesn't post any chemicals outside the USA;
odd as their distribution centre is in GERMANY
at this rate i'll be hand-chiselling boards!
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gizo
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Posted on Tuesday, 03 April, 2012 - 10:55 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

That article seems to produce good results.

However a bit of a worry he keeps mentioning _inkjet_ transparency use in a laser printer.

This has always been frowned on because the laser toner fusing during printing is created with very high temperatures which could produce disastrous results, including damage to the printer, when using plastic not designed for high heat.

Might be adviseable to try heating any sheet being considered before use, to see what happens to it.
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cjaysharp
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Posted on Tuesday, 03 April, 2012 - 07:35 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Definitely a worry, the fuser asembly in a laser printer is not a cheap bit and they tend not to like having molten plastic wrapped around them, many won't survive.

Worth checking if the printer has a transparency mode too, many lasers will drop the fuser temperature if you tell them you're using transparencies.

I've used this stuff from Farnell http://uk.farnell.com/mega/100062/laserstar-film-a4-10-sheets/dp/895945?Ntt=895945

for prototyping and it works really well but I've also printed designs onto laser compatible OHP transparencies and had good results.
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younngjohnnie
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Posted on Tuesday, 03 April, 2012 - 08:03 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Is anybody using an inkjet printer and what transparency film are you using
rgds
John
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gordon
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Hi Younngjohnnie, I am using an HP inkjet printer with JetStar premium transparency film. I think it is a Mega product, but is also sold by Rapid and others. They have a standard film as well, which is supposed to work with Epson printers. I tried it, but it does not work with my HP printer.

I get around the cost (1.50 a sheet) by printing the board outline first on paper, then tape a piece of the film, about a cm bigger all round, in its place with tape. Works out about 14p for a 5x7.5cm board. Mind you, if you use an earth plane/copper fill, I guess the ink costs more than that!. The film gives excellent results. I think there is also a video on Mega, on its use.
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arw
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Posted on Tuesday, 03 April, 2012 - 10:38 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@ Richie

I have posted details of my U V Exposure Timer here:

http://alanwinstanley.com/storage/pdfs/uv%20exposure%20timer.pdf

http://alanwinstanley.com/storage/pdfs/uv%20exposure%20timer%20prototype.pdf

It should still be do-able today if you can match the bits for the pcb (artwork is included).

-- Alan W
Alan W -- EPE

More online resources at www.epemag.net
Personal site www.alanwinstanley.com
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rich13
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Posted on Tuesday, 03 April, 2012 - 10:44 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Im using transpareny with an old HP 2100 @600dpi,very clear image. Had really good results tonite, left exposure bit longer this time 10minutes, ive ran out of developer at present, the missus forgot to get some caustic soda, so ill play tomorrow.
A note regarding the pre-coated boards. On ebay i found only Maplin seeling these.My searching isnt the greatest, but putting various search criteria, Maplin always came back, at £1.99 per board,(small board), is cheaper than shop prices (£2.69 for same size), the downside is, £2.99 postage, tad steap for a small item that weighs less than a nuns bra.

@Alan
Many thanks for the timer details, much appreciated.

(Message edited by rich13 on 03 April, 2012)
__ Rich __
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rich13
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Posted on Wednesday, 04 April, 2012 - 12:56 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Ide like to just re-edit my last post, searching ebay, i found many sellers selling photo resist boards.
I didnt want to look a fool not looking hard enough.
__ Rich __
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younngjohnnie
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Posted on Thursday, 05 April, 2012 - 12:06 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

The jetstar premium transparency film looks a bit expensive.
I found this film for HP printers
http://www.clp.co.uk/Product.asp?Prd=333271.
The film they have sent is not actually as pictured but by maker connect but it seems to print OK on the hp inkjet printer.It certainly doesnt smear as other films I tried which I just happened to have in the cupboard.
Havent tried it for exposure yet but working up to that.
rgds
John
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gordon
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Posted on Thursday, 05 April, 2012 - 12:23 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I will be interested in the results when you get a chance to try that film. Although the the JetStar is expensive, I will get at least 50-100 boards from it, so will probably last my lifetime!
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yorkie
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Posted on Thursday, 05 April, 2012 - 12:57 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I bought 50 sheets of Q-Connect Universal Ink-Jet acetates last year, which worked a treat when using an aging HP printer until recently. The results were first class - the ink dried quickly, has excellent density on the film, the reproduction was perfect and the ink didn't flake off the acetate. Customer reviews also rated it highly.

Q-Connect KF26074 Universal Inkjet transparency film:

Q Connect Universal Inkjet OHP Film. Clear, A4, OHP film suitable for use in inkjet printers. Features include: excellent ink reception, good drying times and coating on one side.
http://www.amazon.co.uk/INKJET-CLEAR-PRINTER-ACETATE-SHEETS/dp/B000KJO7BO

50 x A4 INKJET CLEAR PRINTER ACETATE FILM OHP SHEETS
________________________________________
RRP: 69.20
Price: 14.52 (24.20 / kg) & this item Delivered FREE in the UK with Super Saver Delivery. See details and conditions
You Save: 54.68 (79%)

Then my HP printer died on me, and having heard good reviews of the Epson SX535WD 'three-in-one' (printer scanner, copier), the blurb for which boasts 'lab quality prints' I assumed that it would print onto acetates at least as good as my old HP Photosmart. Silly me - the results on ink-jet acetates are dire and no use for my needs. I've tried printing two and even three acetates and placing them one on top of another. Hold them up to the light - they've got gaps in the printing. I've also tried to run the acetate through the printer twice its next to impossible to get it to register accurately. When googling 'Epson+acetates' other users remarked on how poor Epson was for PCB acetates, and in one case, blamed the acetates - not the printer.

When I bought this printer, (which works well enough on paper, but soon sucks the tiny cartridges dry), I'd assumed - mistakenly it now seems - that all modern printers support ink-jet acetate film, and initially I wondered if I'd got the printer on the right setting. I tried all available settings for text, enhanced text and every photo-paper setting, all to no avail, so I called Epson's 'Helpline', spoke to a support person who checked with his supervisor and confirmed to me what I suspected was the case (and charged me for the call!), namely, few home/office Epson printers support the use of ink-jet acetate film.

To make matters worse, in the four months that I've had it, the price of the printer has dropped by 50% of what I paid, (which was 40 less that the RRP), to little more than the price of a set of genuine Epson cartridges, which are expensive and have low capacity. 65 for a printer and 48 for a set of genuine cartridges? What's that all about? What's the worse thing that can happen if I use cheap 'compatible' inks at 19.00 a set - my printer head might clog? So? The printer is destined for landfill anyway.

In their blurb, they tell you what the printer can do, but don't tell you what it can't do. When I've used up my cartridges, (which at the rate they empty won't be long), this printer - just four months old months old, will have to go, and I'll research alternative printers which are up to the task, which will rule out Epson.

Maybe with Powerpoint presentation having tended to displace OHPs, just as OHPs tended to displace flipcharts, Epson don't see the point of supporting OHPs. But they don't tell you that in their hype. I'd rather hoped that it would be a printer driver issue which could be corrected - not a design shortcoming. I then found this comment on internet - according to the writer, it's not just Epson no manufacturers maker will say that their printers will print onto acetates:

Quote:

Printing on Vellum and Acetate - TIPS:

Some people find it tricky to print on Vellum and Acetate - so I thought I would post some standard words I use when trying to answer peoples queries: Firstly no printer manufacturer will say yes this prints on acetate or vellum because all home printers are designed for standard papers and none are designed for crafters - but thousands of people print on vellum and acetate every day (on their standard printer) - it just takes a bit of patience and learning what your printer likes...

End quote.

Source: http://www.joannasheen.com/tuition-advic...tate-tips/

Hmmm, before I ditch the printer, maybe I'll try a different type of acetate, albeit the Q connect ones that I have were excellent with HP.

Found this too:

Quote:

Just before Christmas my printer died and I bought an Epson, I'd previously had HP and Canon.
I have discovered today that the Epson wont print on acetate or vellum...

End quote.

Read more: http://www.pcadvisor.co.uk/forums/1/help...z1qXl0Mayb

Hope that's of interest.

David
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gordon
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Posted on Thursday, 05 April, 2012 - 01:15 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I also used to use 2 or 3 PCB artwork transparencies on top of each other, to get the ink density required, so I was probably spending a lot on ink anyway. Printers are so cheap now, even with scanners, that I sometimes wonder if it is worth buying a new set of cartidges. Ink is where the money is, and at about a 1 per ml, no wonder there are at least a few hundred different cartridges for all the inkjets out there.
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younngjohnnie
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Posted on Thursday, 05 April, 2012 - 02:16 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

David
thanks for that. I am returning the ones I bought from CLP and have just ordered the Amazon ones. They are 10.00 cheaper for the same item.
If this hadnt worked with the inkjet I was just going to buy a small laserjet printer. They only cost about 65 and come with enough toner for 700 pages.
regards
John
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yorkie
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Posted on Thursday, 05 April, 2012 - 08:41 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I wonder if anyone on here can comment on the opacity obtained on laser acetates? some years ago before I had an ink jet printer I used to take magazine artwork to photocpying shops and get them to copy the artwork onto acetates on their laser printers. Very poor - you could just about get away with it with three on top of each other, but with just one, if you held it up to light you could see right through the tracks. Of course, technology has move one and entry level lasers might be fine for all I know. I know that there's lots of stuff on internet about using a laser printer onto photopaper then using the iron-on technique to bond the tracks onto the PCB, then to soak off the paper leaving just the track on the PCB ready to etch. It all sound rather too good to be effective!

David
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terrym
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Posted on Friday, 06 April, 2012 - 01:50 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I have 2 different laser printers that I use for pcb's.

A HP 4L that must be 30yrs old now and still working well and an Epson ALC900 colour printer.

My preference is for the HP unit, it prints a dark enough sheet with extremely few pinholes (seems to depend on acetate), that only one sheet is needed. You can also set the amount of toner deposited between light and dark.

The Epson is acetate sensitive, but with the right one does an OK job.

I don't actually use general purpose acetates anymore, but use a product designed for the job - Novasharp Diamond laser printer film by Technova. It is a bit more specialised, I get mine from a printer's supply company. Worked out to approx $1AUD per sheet and comes in boxes of 100 sheets. There is also a solution that can be bought to spray on the film that sets and darkens the toner and removes pinholes, but I don't use it.

TM
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joe
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Posted on Friday, 06 April, 2012 - 04:52 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I gave up on those clear acetate sheets years ago as I seemed to get inconsistant results and were expensive.

I now use a HP2600 laser printer, and tracing paper sheets : http://www.ebay.co.uk/itm/140306813548?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
at around UKP 14 for 100 sheets.

Have a look here: http://www.hobbyelectronics.net/tec_making-pcbs.html
for some close up images of printing on different paper types.

Regards,
Joe
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yorkie
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Posted on Friday, 06 April, 2012 - 08:47 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Excellent stuff Joe - how you must have suffered for your art, with many failed attempts on your 'voyage of discovery' to get to where you now are! Tracing paper sounds like an excellent altrnative to acetates, so I'll give that a try. Do the plain areas of the tracing paper impede UV to any extent, or is the paper in effect, transparent to UV light? (I've heard it mentioned to spraying the paper with WD40 makes it more transparent, and I do have an aerosol spray of 'transparentizer' which I believe artist use to transparentize' paper in some applications).

The extent of the postings to this thread certainly shows that there is much interest in DIY PCB making!

David.
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joe
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Posted on Friday, 06 April, 2012 - 09:02 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

It's an interesting ongoing voyage, thats for sure.

I'm not sure how much the tracing papoer impedes UV. However, I use a UV box from Mega (twin tubes) with a custom timer. I expose my pre-sensitised board (from Rapid) for ~90 seconds after I've allowed the unit to warm up and I get good results.

I then use sodium hydroxide (Caustic Soda); 2 cap fulls (those red caps that are supplied on the top of a can of WD40) into 5L of heated water.

Regards,
Joe
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younngjohnnie
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Posted on Friday, 06 April, 2012 - 04:10 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

David
Roughly what is the concentration of Metso you are using for developer.
regards
John
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arw
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Posted on Friday, 06 April, 2012 - 06:18 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I agree with Joe's methodology, and I use matt polyester film for artwork, it's very much like tracing paper to look at, and never had any problems with exposure.
Alan W -- EPE

More online resources at www.epemag.net
Personal site www.alanwinstanley.com
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gordon
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Posted on Friday, 06 April, 2012 - 06:37 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Yorkie, you may have seen this site before, but it suggests tracing paper as a good medium for Laser printers. A long time ago I tried it with inkjet, what a mess!

http://www.electricstuff.co.uk/pcbs.html
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yorkie
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Posted on Friday, 06 April, 2012 - 09:09 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Thanks for the link Gordon - I notice that the article refers to Epson Stylus printers being US for this application, but HP better. My old HP, with no fiddling with the settings, printed perfectly onto acetate with dense black lines totally opaque. Epson Sylus SX535 - waste of time. Just tried it on tracing paper - useless. I'd rather hoped when I bought it that it would be at least as good as my old HP printer, given that Epson boasted 'lab quality prints'.

I think that as has been said, a cheap B&W laser printer may be a favoured option.

As to the Metso concentration query by younngjohnie, the instructions state 25g per one Litre and that the board should develop in 30 secs. I find that far too strong, so start with 10g dissolved in warm water, then if it seems not to remove the exposed lacquer, I add a small amount more of crystals at a time, till it will dissolve the lacquer in a minute or so. I have a container of clear water into which I put the PCB as soon as it's developed, because if you don't, there's a risk that it will dissolve the tracks. (If you leave unexposed board in for several minutes it will dissolve the lacquer).

There are so many variables, that however much I've tried to eliminate the guesswork, it's always a bit hit and miss, but I've had many more successes than failures!

David
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rich13
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Posted on Saturday, 07 April, 2012 - 12:30 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Just a quickie update
I had a really good result, Just one daft error, the board was back to front, I wasnt wasting it, so carried on with it.

Im still having ups and downs with developer solutions, i think this board was plain luck. As the next two i did, the developer mix just stripped the board. After the kitchen looked like a mad chemists workshop, the missus gave me marching orders to clean up. So with the week end, im hoping to crack this.
Yorkie spoke of spraying tracing paper with WD40, I read on the same lines of soaking lightly with vegetable oil.

Have a good weekend all....
__ Rich __
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arw
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quote:

As the next two I did, the developer mix just stripped the board.




The developer was far too strong then - start with nothing and gradually add small amounts.
Alan W -- EPE

More online resources at www.epemag.net
Personal site www.alanwinstanley.com
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joe
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Posted on Saturday, 07 April, 2012 - 06:41 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

...and/or the developer was too hot.
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gordon
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Posted on Saturday, 07 April, 2012 - 02:44 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Once you find the concentration of developer that works with a particular brand of board, you should be able to get consistant results. Using the Maplin brown resist boards in the past, they have needed about double developer strength, over the green resist boards from Rapid.
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rich13
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Posted on Sunday, 08 April, 2012 - 08:13 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Just my luck Maplin were out of stock of pre-resist boards, as im away to sunny Wales for the next five days, thats enough time to get some ordered in. Until then my friends,speak next week, and again thanks for all the help.
If you dont mind , ill let you know the outcome (only when ive got a result)

(Message edited by rich13 on 08 April, 2012)
__ Rich __
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mee
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Posted on Monday, 09 April, 2012 - 12:51 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi all. I've made scores of boards in the past, but my experience with pre-coated products has been largely negative. The main problem as I remember it was that pre-coated boards seemed to vary widely in performance (mostly due to shelf life probably). That made it impossible to work out a procedure. Maybe things have changed, but even so, some of the following may help.

I bought very large sheets of double-sided high-quality board from a wholesaler so that I could experiment at relatively low cost.

After many trials using spray-on UV sensitive coating, I came up with the following:

Purity of the copper on the surface of the PCB to be sprayed is crucial; no oxide, no oil, no foreign particles, no burrs left over on the edges. Once you've got the board to that state, use it within minutes preferably seconds.

I made a turntable (why will follow) from a 15in MDF circle leftover over from making a loudspeaker cabinet. It ran horizontally. A bolt through the axis of the MDF was driven by an old B&D drill that could be permanently turned on while running at a few rev/min.

I remember reference to problems with dust from earlier posts.

Simply clean the air in the environment that you're going to do the spraying in. I did it by running a vacuum cleaner with a fine particle filter for a while before spraying.

Leave the vac running if you can stand the noise. And while it does its work, grab a hair dryer.

In summary, I see loads of ultra-clean PCBs rotating on an MDF turntable in a darkened room with a vacuum cleaner running in the background.

Depending on your environment, warm the PCBs with the hair dryer then give them a last dust-off with a lens brush.

Now spray them. Don't squirt. But puff. The turntable ensures that you get an even coating. My 15in turntable allowed me to make many tiny experimentation pieces.

If you are confident that the vacuum cleaner is doing its work, dry the layer with the hair dryer.

Then puff again...

If there's anything of interest here I may be able to elaborate. I never had any luck with the WD40 and stuff relating to producing transperencies. The only comment that I think may be useful is that there have been articles that describe how transparencies can be passed through printers more than once.

Good luck. Cheers, M
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mee
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Posted on Monday, 09 April, 2012 - 12:54 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi all. I've made scores of boards in the past, but my experience with pre-coated products has been largely negative. The main problem as I remember it was that pre-coated boards seemed to vary widely in performance (mostly due to shelf life probably). That made it impossible to work out a procedure. Maybe things have changed, but even so, some of the following may help.

I bought very large sheets of double-sided high-quality board from a wholesaler so that I could experiment at relatively low cost.

After many trials using spray-on UV sensitive coating, I came up with the following:

Purity of the copper on the surface of the PCB to be sprayed is crucial; no oxide, no oil, no foreign particles, no burrs left over on the edges. Once you've got the board to that state, use it within minutes preferably seconds.

I made a turntable (why will follow) from a 15in MDF circle leftover over from making a loudspeaker cabinet. It ran horizontally. A bolt through the axis of the MDF was driven by an old B&D drill that could be permanently turned on while running at a few rev/min.

I remember reference to problems with dust from earlier posts.

Simply clean the air in the environment that you're going to do the spraying in. I did it by running a vacuum cleaner with a fine particle filter for a while before spraying.

Leave the vac running if you can stand the noise. And while it does its work, grab a hair dryer.

In summary, I see loads of ultra-clean PCBs rotating on an MDF turntable in a darkened room with a vacuum cleaner running in the background.

Depending on your environment, warm the PCBs with the hair dryer then give them a last dust-off with a lens brush.

Now spray them. Don't squirt. But puff. The turntable ensures that you get an even coating. My 15in turntable allowed me to make many tiny experimentation pieces.

If you are confident that the vacuum cleaner is doing its work, dry the layer with the hair dryer.

Then puff again...

If there's anything of interest here I may be able to elaborate. I never had any luck with the WD40 and stuff relating to producing transperencies. The only comment that I think may be useful is that there have been articles that describe how transparencies can be passed through printers more than once.

Good luck. Cheers, M
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cjaysharp
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Posted on Monday, 09 April, 2012 - 09:38 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@Mee

Best tips for pre-coated boards I was ever given were to buy them from somewhere with a good stock turnover (Farnell, RS etc), to store them properly (fridge) and use them fairly quickly (a week or two). At any self service shop I could imagine boards having been there in varying ambient temperature for months.

Years ago I've bought them fresh off the production line at a local PCB house and they needed a ridiculously short exposure time (they were also opposite to the norm, had to make 'negative' transparencies) but I'm not sure how I'd fare trying that today.
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gordon
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Posted on Monday, 09 April, 2012 - 01:29 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Mee, That is a neat system for making your own precoated PCBs. I also used to coat boards in the past, but for the quantity I need/use, the cost saving is not really significant. With precoated boards, I have had very consistent results, even with pieces of board several years old. Can't say I have ever noticed a big difference in the UV exposure time needed for older resist coated boards.
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zeitghost
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Posted on Wednesday, 11 April, 2012 - 11:09 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Dunno about the shelf life thing.

I've had success with boards from 1986.

You just need to dial in the exposure time and developer strength to suit.

Which can be a bit of a pain.

Unless you're mean, like me.

One of the biggest blunders was thinking that a ruby coloured plastic coating was the etch resist.

Which it wasn't.

Oh, how I laughed.
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cjaysharp
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Posted on Wednesday, 11 April, 2012 - 11:43 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Zeitghost, I agree in principle (I'm mean too) but if you're not sure of the process in the first place or are trying to make a few boards then having 'fresh' boards can be invaluable, it lets you set up the process and almost forget it because the results are consistent and predictable.
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younngjohnnie
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Posted on Wednesday, 11 April, 2012 - 03:00 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I built my UV light box at last.
UV Box 1
UV Box
I used these tubes : - http://www.lamps2udirect.com/pages/fullProd.php/8-Watt-T5-Blacklight-BL350-UV-Actinic-05-Ultraviolet-Fluorescent-Tube/543. You dont actually get Sylvannia ones but the ones supplied work. Cost only 4.01 each including VAT.
I used these starters:- http://www.lamps2udirect.com/pages/fullProd.php/S10-4-65-watt-Fluorescent-Starter/427. Cost 0.44 each including VAT.
I used these Ballasts:- http://uk.rs-online.com/web/p/lighting-ballasts/6657605/ Cost:- 7.20 each including VAT
I used these lamp holders:- http://uk.rs-online.com/web/p/lighting-ballasts/4422820/ Cost 0.75 each including VAT
I used these Starter holders:- http://uk.rs-online.com/web/p/lighting-ballasts/562019/ Cost 0.72 each including VAT
I used this mains socket:- http://uk.rs-online.com/web/p/lighting-ballasts/488191/ Cost 1.40 each including VAT.
These were my choices I am sure there are better ways but it has worked for me.
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younngjohnnie
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Posted on Wednesday, 11 April, 2012 - 03:08 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

And having built the light box my first board. I am so happy it worked.

1st board

This was a test strip exposed in steps of 1 minute from 1 minute to 6 minutes.
Exposure seemed to be fairly insensitive from 1 to 3 minutes. After that the developer started to destroy the image.
The board I used was from Rapid. http://www.rapidonline.com/Tools-Equipment/Economy-Ss-Photoetch-233-4-X-220-34-0166
The film I used was Connect KF26074 (http://www.amazon.co.uk/gp/product/B000KJO7BO) printed on a HP OfficeJet Pro 8500.
I developed it in Metso (http://www.ebay.co.uk/itm/140667072644?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649) I used 15grams per litre. Temperature of the developer was 25C. Developed in 30 seconds.
I etched the board using sodium persulphate (http://www.ebay.co.uk/itm/280735186841?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649) I used 100grams per 0.5 litre. Starting temperature was around 45C. Etching was very slow when solution cooled until I put the tray in a water bath of hot (~60C) water. Etched then in around 5 minutes.

Things to do next.
I need to get a heater for the etch. I have seen someone say they use an aquarium heater. Any recommendations on the wattage needed.
I need to figure out how to make the artwork from scratch. (for my test I used a random circuit downloaded from the internet). What are people using for pcb artwork creation.
Do I need to tin the board.
And finally a big thank you to everybody on this board who have pointed me in the right direction.
regards
John

(Message edited by Younngjohnnie on 11 April, 2012)
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yorkie
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Posted on Wednesday, 11 April, 2012 - 04:54 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Re the heater, if you use sodium metasilicate ('Metso) as an etchant, the instructions say that it works best at between 45C - 50C (about 120F)

http://www.ebay.co.uk/itm/ws/eBayISAPI.dll?ViewItem&item=270746775207&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

I use a 25W aquarium heater in a plastic cereal container as an etch tank and use an infra red thermometer to check the temperature. For aquarium purposes, a 50W heater is used for a fish tank of 20 50 Litres 5 124 Gallons, so for an etchant tank containing say no more than 2 Litres, it will come up to temperature quite quickly.

However, most are thermostatic, so you need to try to find one that isn't (mine isn't), because the range of the thermostat is usually a max of 34C (93F), which isnt hot enough for our purposes. I think that ordinarily, the temperature of a tropical fish tank should be around 25C 77F, so a thermostat is desirable for the purpose for which the heater is intended. Theyre not expensive invariably under 10.00. Heres a typical example:

http://www.ebay.co.uk/itm/Aquarium-Heater-50W-with-thermostat-/250954615927?pt=UK_Pet_Supplies_Fish&hash=item3a6e0f8c77

I doubt that the temperature of he etchant is all that critical, and 34C is actually quite warm, so such a heater might be OK. It may just take a little longer for the etchant to work, but that can be counteracted by making the solution more concentrated.

When mine is up to temperature I switch the heater off, remove it from the tank, and put it in a bowl of cold water to cool down. I then put the PCB in the etch tank, and start an aquarium air pump to pump bubbles through the etchant through a 6 long aquarium airstone in the bottom of the container.

Theyre widely available at pet shops such as Pets At Home, or on internet:

http://www.swelluk.com/aquarium/air-pumps-accessories-9.html

As to tinning, you can get tinning crystals from places such as ESR Electronics, which come in a plastic bottle. You fill the bottle with water and shake it to make the solution, then immerse your etch board in the solution to tin it. However, both the crystals and the made up solution have a short shelf life, and it's expensive. I did buy a bottle some years ago, but the time I got round to using mine a few months later, the crystals had 'gone off' so had to be chucked away. Personally, I smear the etched PCB with flux, then apply some solder to a soldering iron tip, and run the tip quickly over the tracks, making the solder just a thin coating on the tracks. It's surprising how far just a little blob of solder on the tip of the iron will go. It's vital of course to then wash the board thoroughly to clean all traces of flux from the board or it might attack wire connections over time. I've done this for many years now and find that it's the easiest, quickest and cheapest way to tin my boards.

Hope that helps.

David
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twintub
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Posted on Thursday, 12 April, 2012 - 12:23 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

youngjohnnie,

You've missed something from your parts list: What's the component to the left of the terminal block - A capacitor?
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younngjohnnie
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Posted on Thursday, 12 April, 2012 - 09:24 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Twintub
Yes it is a lighting capacitor. I dont have a part number for it as it came out of an old fluorescent light fiting. Its marked 240V 6uf but actually measured at 3.7uf.
regards
John
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mikeb
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Posted on Thursday, 12 April, 2012 - 11:45 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@YJ

Nice job and a very nice board.

Getting thin tracks is essential if you are going to Eagle as your CAD package and there is a growing need to insert SOIC/SMD stuff.

Having read Rich's remarks reference eye damage, I intend to install a lid cut off switch.

I predict you will soon be tempted to the Dark Side, Luke ..... (double sided).

rgds

mb
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arw
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Posted on Thursday, 12 April, 2012 - 05:15 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Nice job. Do UV exposure units have high voltages in them?
Alan W -- EPE

More online resources at www.epemag.net
Personal site www.alanwinstanley.com
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younngjohnnie
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Posted on Thursday, 12 April, 2012 - 05:29 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Its all relative.
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rich13
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Posted on Thursday, 19 April, 2012 - 10:53 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hello all..

Recieved the 'Metso' and Sodium Persulphate today.
And after an exposure of 5 minutes. I did the board in the picture first time.

Developing took a few minutes, as i was adding metso as i went along.Temperature about 25c Etching approx 35 minutes @approx 55c.
Im still using the transparency sheets, but i get good results with tracing paper, which obviously is cheaper.
The caustic soda i just could not get on with, i just could not get the correct balance.

Im re-doing the exposure box, as Youngjohnies put mine to shame.

Ive included piccys.While etching, and final board(which i need to clean and drill)

Im a happy bunny,..

Thanks everyone for the help..



pcb

(Message edited by rich13 on 19 April, 2012)
__ Rich __
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terrym
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Posted on Friday, 20 April, 2012 - 07:27 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Well done, perseverance pays off.

TM
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younngjohnnie
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Posted on Friday, 20 April, 2012 - 08:16 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Rich
Its a great feeling to get success. Well done.
Etching seemed to take a long time. I put my tray in a tub of hot water which kept the temperature up during the etching which I think speeded it up. Still looking at heaters to maintain an even temperature
John

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