READ THE INSTRUCTIONS before you start! You are using chemicals and must observe a minimum safety standards!

H2O2 Hydrogen Peroxide
H2O Water (distilled)
HCl Hydrogen Chloride (Muriatic Acid)

Percentages for PCB development:

H2O2 Solution: HCl Solution:
% %

Solution: H2O = ?,  HCi = ?,  H2O2 = ?

Enter the concentrations of products and press calculate


Whatever etchant you use, you should wear safety gloves, because you don't want to get any substance that dissolves metal on your skin. Safety goggles are also a good idea to prevent accidental splashes from getting in your eyes. It's obvious that you can't use a metal container to perform the etching. Especially aluminium with a HCl-based etchant is a very, very bad idea unless you're aching to get into massive trouble.


To create the mixture without the risk of it splashing around, start with the water, add the HCl and finally the H2O2. The water should be distilled, although tap water might also work (probably just not as well). Do no heat the solution, it works perfectly at room temperature. Heating it will cause the peroxide to break down rapidly. Etching with the HCl solution takes only a few minutes. The solution will turn green from the copper oxide dissolving in it. Agitate the solution a bit to speed up the process even more. There's no need to use a bubble tank. You will want to be able to get the board out of the etchant as soon as the last bit of copper is etched away, to prevent over-etching. You can either use plastic tweezers, or drill a hole in the PCB before etching, and stick a nylon cord through it, which will make fishing out the board piece o' cake. Have a tub with water handy, to wash off the etchant immediately.