Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

I am using HCl (31%) + H2O2 (30%) + water in the ratio of 3:1:3 at
room temperature with manual agitation (rocking) to etch some boards,
but I'm having some problems. The boards seem to take a long time to
etch (>15 minutes), and rather than etching evenly, the edges of the
board etch first, then the perimeter of the non-etched area gradually
decreases. I'm concerned that the etching from the edge will undercut
the traces. What am I doing wrong? Other people report even etching
in 1-5 minutes with this mixture, so I must be doing something wrong!
Thanks for any help.

Mark