--- In
Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
>
> I've always used 3% but in this case, you only need the H2O2, not the
> water it's diluted with. If you have easy access to stronger H2O2, go
> ahead and use it.
>
> Another option is to heat up the FeCl to make it work faster. I just
> float the bottle in some hot tap water for a while.
>
An aquarium heater works well and they're cheap. I accidentally broke the one I I got at a garage sale and a brand new one was only $10 on ebay.
I use cupric chloride now but with either etchant it shouldn't take longer than 3-4 minutes to etch. Too slow and you can get pitting.