I have been etching things the cheap and simple way, just trying to get the hang of etching. Now I want to step it up a notch. I have a UV-light source and everything to expose the brass, but I can't find the resistive coating needed for doing a positive exposure. There wasn't any problems a few years ago to find the coating in a spray can, but now it seems like electronic stores have gone over to having the coating already on the copper piece.

What is the coating called in English? What is it exactly. I understand the UV-rays are aging the un-covered areas and that allows for the solution to take them away. I was kind of wondering if maybe a laytex coating would work....

Happy New Year!!

Maybe these links will help?

http://www.largescaleplanes.com/tips/RatoMarczak/etching/pe_at_home_1.html

http://www.prototrains.com/etch1/etch1.html

It is called "resist". It comes in rolls, as a plastic film that has a photographic emulsion that is bonded onto the plate with heat, and the plastic discarded. When a film or negative is placed on top of it and it is exposed to UV light, the exposed emulsion is chemically altered, as in photography, and dissolves away when the plate is "developed". This leaves bare metal, which is attacked by the "etchant" and corroded away. Ferric chloride is common in radio shack kits, but ammonium hydroxide works just fine for copper alloys like brass. When it comes out of the etching bath it is "fixed", rinsed clean, and hung to be broken up or plated.

HTH / Happy New Year
Scott Fraser

Matt: Thanks for the links. Always good to get another view of how someone else did it

Scott: Thanks for the explanation. How interesting that you say it comes in rolls. The only resist I know of has been in a spray can. I've etched circuit-boards before and then I took the copper-clad board and sprayed a thin, even coat with the stuff. If I can't get a hold of the resist, I was hoping to be able to mimic it somehow. It would be good to know what chemical composition it is...

I think I've found the answer to my woes!!!

I have a laser printer and this guy says you can use photo paper to add the pattern to be used. I haven't tried it, but I surely will soon...

Using a laser printer to mask for etching

Micro Mark Sells it!

Thanks Greg!! I thought I had looked extensively through Micro Mark's website. I have a laminating machine, but am unsure how the resist works. Is the resist like a normal laminating sheet? Or do I need to use something other to back the metal sheet with?

I am just getting into it. JBA has me so pumped up with his work, I could pee myself. The Micro Mark set seems to me like a good place to start. To answer your question, I think the resist just blocks the light. You can also check this video out from renaelectrontics. Maybe you could call them and ask some questions...let me know what you find.

Sorry Greg! I know the resist blocks the light, what I meant was I'm not sure how to apply the resist in the form/shape/manner it is. If it is just like a laminating pocket then there are no problems. If it is meant to be laminated only on one side then the other side needs to be protected somehow, and that isn't the hardest thing to deal with...

I'm going to try the laser printer mask to see how that works. If I can't get that to work I'll have to try the stuff from Micro Mark...