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

Just thought I would describe my experince using muratic acid and
peroxide to etch a couple of boards. I used a plastic shoebox the semi
white flexible kind poured in 1 cup 3% peroxide and 1/2 cup 32%
muratic acid (swimming pool type) added slowly. the acid was about 40
degrees as I store it outside. no fumes or bubbling was noticed during
this time. The liquid was clear. Put in the board which was covered
with riston dry resist and touched up with a sharpee. the exposed
copper immediatly turned dark reddish brown and the solution turned
emerald green in about a minute. Very pretty and quite clear. The
board was 6" by 3 1/2" it was totally etched in less than 5 minutes. I
used a gentle rocking motion. At no time did any noticable fumes come
off the process. About 20 minutes later I started etching another
board about the same size. When I started I noticed many bubbles had
appeared on the bottom of the shoebox. the board etched much more
slowly. I added about 1/2 cup peroxide and it sped right back up. When
the second board was complete I neutralized the acid by slowly adding
backing soda. when the fizzing stopped I diluted what was left and
poured it down the drain. I realize it can be regenerated over and
over but due to the small amount needed to etch the board and the fact
I am very interrmittent in my etching needs making small amounts fresh
seems like the thing to do. I believe what I ended up with was the
cupric etching solution and if so it is MUCH faster starting with
peroxide insted of bubbling for a week to get it started.