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

When I ran a commercial shop we used a 1% solution of soda ash for
developing dry film. We ran out of soda ash once and used Tide
laundry soap. It worked good on DuPont 4715 dry film but we had to
use some defoaming agent. I think for small batches of boards this
would work fine. Don't worry about the suds unless you are running
larger volumes in a spay developer. Store bought lye works good for
stripping the resist from an etched panel.

When using a Kepro spray etcher as a developing unit for dry film,
make sure the soda ash solution is drained from the sump when
finished. Jim Keil who owns Kepro told me that this solution will
destroy the plastic pump bodies if they are exposed to soda ash for
long periods of time.

I have several of these Kepro etchers for sale if anyone would be
interested. I use one with ferric chloride and the etching time is 3
to 5 minutes depending on the copper weight.

Tom