Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

I have to thanks the members of this group (and possibly others) for two ideas. First is the use of HP presentation paper for toner transfer rather than the Staples glossy photo paper I was using. The removal of the paper is comparatively simple. I'd been fighting with the photo paper for years. Removal of thepaper residue being the biggest problem.
Second, I made some Cupric chloride according to the intructions from an internet link I think presented here (search Etching with Air Regenerated Acid Cupric Chloride). Although making it is a bit nasty (fuming HCL) and time consuming (about 2 weeks), it is fine once created and works incredibly well. Best of all it can be regenerated and used again. Also it is a lot less messy than ferric chloride (and cheaper too).
The Cupric chloride etched my board in 3 minutes at room temperature using a sponge brush to swab the board. The toner stood up to it perfectly. I'm considering a bubble tank or a spray system in the future to speed things up even more.
I'd like to add that I think the direct use of HCL and Hydrogen peroxide - although they can be ingredients to make Cupric Chloride - are being mis-interpreted as to be used directly to etch boards. I think this is why so many mention they have problems with it. I think the acid is much too strong.
After reading the article carefully it is apparent that it is actually the CU+2 ions produced by making the Cupric Chloride properly that does most of the etching not the acid so much. The article also mentions another link to a site describing the way Cupric chloride is used commercially so it is a valid etchant. The straight HCL and hydrogen peroxide are nly is only a means to an end.

I'm going to start using both of these now. They have certainly improved my results.


Sage