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Subject: Re: [Homebrew_PCBs] Re: VERY FIRST PCB -- SUCCESSFUL!!!

From: Erik Knise <elknise@...>
Date: 2011-10-19

At 20% concentration of HCL and 3% (standard over the counter
pharmacy) H2O2 you should have a ratio of ~1:3 by weight (volume is
about the same). So you would need 3 times as much H2O2 to HCL. The
board should have etched within a few minutes.

I wrote a calculator a while ago for Cupric Chloride ratios.
http://www.totse2.com/easy-e/cupricchloride.html It's a bit on the
confusing side and I plan to re-write it eventually but I hope it's
helpful to some people.

I've never tried The Works because I use regular HCL I bought from a
pool supply store. I have more than enough to last me thousands of
boards.

--
Erik L. Knise
Seattle, WA

On Wed, Oct 19, 2011 at 9:04 AM, Chuck <chuckknight2003@...> wrote:
> Okay, in answer to the questions people have asked:
>
> The recipe was simple.  2:1 ratio of H2O2 to HCL.  The HCl was 20% concentration, in a toilet bowl cleaner called "The Works" that I purchased at WalMart for $0.94.  The H2O2 was also from WalMart, from the pharmaceuticals section.  Whatever they had...
>
> Chuck
>