ljcox

Some years ago, I made some PCBs using the photo resist method. 2 were imperfect so I did not etch them.

I now want to remove the exposed photo resist so I can use the boards to make new PCBs using the press n peel film method. I want to use these since I have not done the P n P method before so I want to practice on these.

Does anyone know how I can remove the photo resist? It is a purple colour.

I tried metho but it did not work.

__________________
Len

j.p.bill

It should peel off if you soak the board in the developer. If it's positive resist, exposure to light will spped the process.

ericgibbs

G'day Len,
I have used a caustic soda/water mix in the past to do this job.
A heaped tablespoon of caustic soda [ or drain cleaner with a caustic base] mixed with a half litre of warm water. Use all PLASTIC spoons/bowls.

Soak the pcb for 10 to 15 minutes and then rinse off the resist.
EDIT:: Wash thoroughly with cold water.

Take care, goggles and rubber gloves.

Regards
Eric

ljcox

Thanks for the response, but I did the PCBs so long ago that I don't have any developer now.

__________________
Len

ljcox

Thanks Eric,
I'll try that. I have some caustic soda some where.

cheers

__________________
Len

spuffock

Acetone, nail varnish remover, will shift it.

Hero999

Just lightly sand it with fine emery cloth or an abrasive block.

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justDIY

I'm not sure if it's called the same outside the states, but steel wool and acetone works great. if this is for your press 'n peel work, the wool will give the pcb a bit of tooth as well, to better adhere the iron-on resist layer.

http://en.wikipedia.org/wiki/Steel_wool

oh, something I forgot to mention in my reply to your PM - a great tip I picked up off someone's website was to file a bevel on all the edges of the pcb, before cleaning and ironing. it doesn't have to be extreme, just enough to nock down the edges so the iron doesn't hang up on them. for a double sided board, remember to do both sides.

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philba

acetone works great. I wouldn't use steel wool though. It tends to leave bits of steel in the softer copper which then rust. I just use a paper towel and wet it with acetone. A few wipes and the board is clean. A quick burnish with 600 grit paper prior to using the board will "activate" the copper(ie remove any surface oxide and increase surface area).

ljcox

Thanks for the advice. My wife's nail polish remover is non acetone, but I tried it anyway without success. It smells like metho.

So I'll go out and buy some acetone npr.

Thanks philba for the tip re steel wool. I've seen several references to its use for cleaning PCBs and so I may have used it.

__________________
Len

Rolf

Other things you might try; paint remover, paint brush cleaner, oven cleaner.

justDIY

ive been cleaning pc boards for years with steel wool, never had one "rust" or noticed any steel embedded in the copper.

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If you don't have a planet, what good are gold bars?

want to contact me directly? gmail gordonthree
check out my project website: http://projects.dimension-x.net
Favorite numbers:
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philba

look at it under a microscope. It may not matter much but you can get pits. I've seen this mentioned in the literature.

ljcox

Thanks for the suggestions.

I tried acetone yesterday and it took quite a lot of rubbing but most of the resist came off.

I then tried paint brush cleaner on the other PCB but it only had a thinning effect on the resist. I'll use acetone on it today.

__________________
Len

ericgibbs

hi Len,
Have you had the chance to try the caustic liquid

Eric