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Author Topic: PCB diy  (Read 2181 times)
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Well I can't imagine it's cool to drink that stuff smiley-wink
And if you have kids and/or pets in your house, I would be hesitant as well.
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I do mine on the stainless steel sink in the kitchen.
Ceramic sinks would be just as resistant in case of spills.
I do my etching in sealed food containers to prevent spills.
You can leave the chemicals in the sealed container till you need them again.
Food grade plastics are proof against the etchants just make sure anything used is marked "not for food use".

Ive seen no staining or marking on the surfaces and as its on the drainer if anything does spill its easy to dilute and wash down the sink.

Gordon
Have you ever spilt ferric chloride on the stainless steel?
I though it would attack it

or have you been careful/lucky up 'til now?!?
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Not much so far, but if washed it down quickly.
Now battery acid is another matter, as was the glare I got from the wife.

Gordon
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Not much so far, but if washed it down quickly.
Now battery acid is another matter, as was the glare I got from the wife.

Gordon

yeah
one of those can corrode you quite badly!!! smiley-grin
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I highly recommend a perfboard like this: http://www.radioshack.com/product/index.jsp?productId=2102843#and a circuit writer pen:http://www.radioshack.com/product/index.jsp?productId=3964901. It works great as long as you let the ink "cure" under a lightbulb for 20 min. No quicker way to prototype IMO
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My chemical teacher has given me permission to use the schools lab for PCB making, so now I'm on to the next step, searching for a tutorial. It should cover these things:

  • That all this positiv and negativ etc. stuff is.
  • It should not use to expensive machines, if possible only things you normally have at home or at school.
  • It should use common chemicals. No special things.
  • I need a tutorial on both single and double sided PCBs.

Please help me find a good tutorial,
JanD
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Google for tutorials on "toner transfer" methods.
You need a laser printer or good quality photo copier, your school will have one Im sure.

Read several tutorials they are all slightly different and you can piece together a method to suit your resources.
Each of the steps are documented repeatedly in different guides.

For example,
I use eagle to produce my design for the board.
I print it out on a samsung laser printer on to magazine paper. You will have to experiment with the paper.
The paper is the key part of a successful board with the toner transfer method.
I tape the transfer to the pcb. Single sided nice and easy, double sided take time to line it up.
Ive had very good results with double sided but it is fiddly and may take more than one attempt to line it up properly. But at this stage you can just clean of the toner and try again.
I use an old cheap laminater to heat and transfer onto the board, you can use a domestic iron, Laminater is easier for me and cost about £10.00. I pass the board and transfer through about 6 times turning it over.
I use ferric chloride solution to etch in a sealed tupperware box. You can seal it up and use it again
If any of the traces are a bit sketchy touch it up with an etch resist marker pen, or marker pen, sharpies are quite good.

Heres one I did earlier:
http://scratchpad.thisandthose.org/scratchpad/article.php?story=20100715160140327
This was only about my 4th attempt at a board.
Double sided and fairly fine traces, just one small mistake on one pad on the wrong side of the board. So theres no reason why you shouldnt be able to do something similar with a little research and practice.

I could give you a list of resources but you would get the same results from googling "Toner transfer method".
http://www.google.co.uk/#q=toner+transfer+method

Good luck,

Gordon
« Last Edit: February 19, 2011, 06:22:40 am by GordonEndersby » Logged

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Thanks Gordon,

I've seen the Toner transfer method some times now, is it just to print out the schematic on a bit thicker paper or some sort of plastic and then iron it onto the PCB?

For the etching it self, do I just put my PCB into a bath of ferric chloride and then make so it doesn't stand still and take the PCB out then all traces are etched?

JanD
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I use the thicker magazine paper from the better quality magazines.
Tear out a page with just text on it. Large blocks of colour or black make it harder to see through.
It wont pass through the printer like this so tape it to an a4 sheet of paper with masking tape ensuring the tape dosnt go outside the a4 sheet.
You will read that some have had good results with some photo papers but I couldnt get it to work the toner would not stick to the paper and just made a mess. Old magazines are free!
You can buy special toner transfer paper, but it is expensive.

The ferric chloride needs to be diluted as per the instructions on the bottle.
and yes it is better to rock the container as it will speed up the process.
You want a fairly strong solution so that the etching works quickly and is less likely to undercut the toner mask and keep your traces nice and crisp.
Just keep checking the board until all of the un masked copper is gone.
Its fairly obvious and quite magical to watch the first time you do it.

You can make yourself a bubble tank with a taller thinner container and an air pump from a fish tank but Ive had good results just by rocking the container. All you are doing is moving the fluid so that less saturated solution moves over the board and keeps the reaction going.

Like I said have a good read through the guides until you understand the process.

Gordon
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Some stainless steels do react with acid, note - 'stainless' refers to many different alloys.

There are systems where the acid etching is done sealed inside a zip-loc bag, then afterwards you pour in a neutralizing powder to turn the acid into harmless solid.  Perhaps this is more possible for you?
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Some stainless steels do react with acid, note - 'stainless' refers to many different alloys.

There are systems where the acid etching is done sealed inside a zip-loc bag, then afterwards you pour in a neutralizing powder to turn the acid into harmless solid.  Perhaps this is more possible for you?
Sounds interesting, but I tried to buy some PCB from Dorkbot, and the thing I had the most problem with, the customs, was no problem. So for now I'm going to get my PCBs from there.

Thanks everybody,
JanD
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