--- In
Homebrew_PCBs@yahoogroups.com, "Earl T. Hackett, Jr."
<hacketet@c...> wrote:
> In commercial shops copper was almost always pattern plated followed
by tin, tin/lead, or in the case of HP, nickel gold plating. If you
wanted solder mask over bare copper the tin plating was stripped after
the base copper foil was etched. Plating copper over the whole board
just meant you had more to etch. So antitarnish after copper plate
was never much of a question.
I've had good luck with Cameo copper cleaner (for pans) and a PUR
water filter. A small amount of Cameo in soft water seem to polish
the surface enough that the toner sticks well.
It is important to rinse the board until the water "sheets" over the
entire surface and the PUR filter helps quite a bit if you have hard
water.
Curt