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.
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Peroxide Acid etching
2004-02-13 by klmjr22
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