When I do Kum Boo on Argentium Silver, I anneal and pickle the
silver clean at least once. Once is generally enough.
To me, a slightly textured surface holds the foil better than a
smooth surface, but a friend who does a lot of Kum Boo on AS says
that she does not notice a difference.
If the Kum Boo is the last step, then you can use the thin foils
that are commercially available. If, however, you wish to be able to
solder afterwards, use the thicker foil that Allcraft carries, or
roll your own foil. AS seems to “fade” the gold even more quickly
when heated than SS.
I find that scrubbing the surface with baking soda after pickling
and rinsing gives me much better adhesion. I’m not sure whether it is
the fact that it is neutralizing any pickle left in the pores of the
metal, or that the mild abrasive quality it has is making the surface
slightly rougher. What I do know is that it works better when I do
scrub with baking soda prior to applying the foil.
In summary, the primary differences are:
-fewer heating and pickling repetitions are needed for AS
-If AS with Kum Boo is soldered on, thin gold foils REALLY fade.
I hope this is helpful!