I use this technique all the time. I can do a 2X4 inch, 1 ounce board in about 1.5 to 2 minutes.
I use 1 Part 31% HCL and 2 Parts 3% H2O2. I make just enough etchant to cover the
board about 1/8 to 1/4 inch and lightly brush the surface with a foam Paint
brush. I etch at room temperature. Works very well for me. Make sure your chemicals are fresh, especially the peroxide.
--- In Homebrew_PCBs@yahoogroups.com, "txtom2" <unknown2@...> wrote:
>
> I just mixed up some Muriatic Acid and Hydrogen Peroxide (1:2) and tried etching a very small piece of PC board (cleaned and with no mask)to see how long it takes to etch thru (room temp about 75 degrees F). I saw a change in surface color in a couple of minutes, but no etch thru after 15 minutes. I changed the ratio to 2:2 to increase the acid content and after 15 minutes, no further apparent progress.
>
> Can someone please tell me what I'm doing wrong ? About how long should it take to etch ??
>
> Thanks, Tom
>