Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "Jeremy Taylor" <jt@j...> wrote:
> My chemistry is for Tin/Lead (it' all about the organics, which I called
> brightener thinking of Bright tin which my kit was originally
purchased as)
> This is Solderon BHT-90 series  I could buy the separated Tin con, Pb
> con,Anti foam , and carrier but they offered me a small pre mix to
try it
> out. (RohmHaas directly) I'll be buying the components in the future. My
> solution is yellow.
>  The surface of the plated tin does turns black in the etch, but a
quick rub
> with a scotchbright cleans it up nicely
> 

Jeremy,

If you dip the tin-lead plated panels in straight peroxide (30% or
stronger) for 15 or 20 seconds you will be able to etch without
getting the black film on the plated surface. The plated areas will
still be dull looking but if you reflow the tin lead it will look like
a mirror when you're finished. 

We used LeaRonal Solderon NF for years and used this method to solve 
the black film problem. Even if you scrub the surface it's still in
the holes and could make soldering difficult. Try this peroxide dip
and see if it doesn't make things better.

Tom