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