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I found 500 mL of hydrogen peroxide. It says 12% and food grade.

Normally, before, what I found was 3% only, and there wasn't any note like food grade at all.

Is this suitable while etching PCB? Is having higher percentage (I guess it is concentration of H2O2 to Water) better or worst?

Such product is this.

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  • \$\begingroup\$ Try it out on a scrap PCB. If it's no good then try selling it to a hair stylist. \$\endgroup\$ – Andy aka Aug 15 '15 at 11:29
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    \$\begingroup\$ You can dilute it ~= 1 part HP to 3 parts water to make 3% if desired. Food grade just means "somewhat purer" than some other grades but either is fine. You can use it at 12% and experiment - either use less to start or more and see what happens. DO use an unimportant test piece. 100 Vol or 200 Vol peroxide and 65% HCL etches PCBs in about "... Oops! - WoW !!!! - OK, got another board, lets dilute this a bit ...." seconds. And produces THE most evilly lung attacking vapour I have ever met (and I've met a few). Do it outside, stand upwind and DON'T DO IT :-). Don't try this at home :-) \$\endgroup\$ – Russell McMahon Aug 15 '15 at 13:59
  • \$\begingroup\$ ... (or at work or anywhere - but, wow, its fun to see).... \$\endgroup\$ – Russell McMahon Aug 15 '15 at 14:00
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From my own experience 3% hydrogen peroxide works quite good for PCB etching, the method I used is mixing hydrogen peroxide with vinegar and add some table salt to it, I don't know exact proportions, but usually it is something like 2/3 vinegar 1/3 peroxide(or little more peroxide) and a couple of spoons of salt(depending on the PCB size).

12% hydrogen peroxide is going to do "better", if you can say so. Basically it means that you just don't need to put that much of it to the mixture, so it can be something like 5/6 vinegar and 1/6 hydrogen peroxide.

Note that above mentioned proportions are vague, I haven't tried this method for a year or so, so don't remember exact numbers. I usually tested different mixtures on small blank PCBs of fixed size to check which one is better.

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  • \$\begingroup\$ Can you tell us how much time it takes to etch a pcb with this method sir? \$\endgroup\$ – ChiPlusPlus Aug 25 '15 at 10:37
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    \$\begingroup\$ Depends on the size of PCB, but for me it was quick enough, maybe 20-40 minutes for small pcbs 5x5 cm. Of course make sure you don't have much exposed copper on surface, i.e. make copper pours and stuff, don't waste materials and time for etching leftover copper :) I would still use this method, but now I live in Finland and hydrogen peroxide costs so much here it's easier to bring some ferric chloride from Russia :) I don't know why the hell hydrogen peroxide is so expensive here. \$\endgroup\$ – ScienceSamovar Aug 28 '15 at 5:11

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