I am having difficulty oxidizing 18ct wg is there a different
solution to use, I am trying to use a sulphur based solution but
not having much joy. any suggestions ?
One reason people use higher karat gold, or for that matter, gold at
all, is that it’s resistant to oxidation. You might get 9 kt to
oxidize with one of the commercial “gold/silver” oxidizers, which are
based on more than merely sulphur compounds. But I doubt you’ll get
results with 18K with that route.
enamel, either the fired vitreous version, or the various resin
products that pretend to be enamel, such as “ceramit”,
“ceramitation”, “colores”, and others. Based on either polyester
resisns (ceramit, etc) or epoxy resins (colores), they’re not that
hard to use, and give reasonable results. But they don’t look like a
chemically oxidized surface.
You can also buy “antiquing” solution. These are sold in several
dark colors plus black, along with a thinner. You paint it on, let it
dry, then use the thinner to wipe off excess or to highlight as
needed. I think these are epoxy based paints, though i’m not sure.
They can give a thinner layer than the actual resin products, and
look more like an oxidized surface, though they aren’t one.
Some 18K golds will oxidize a bit when heated, but most don’t turn
more than grey, and the color tends to be blotchy, rather than a nice
uniform finish. But you might experiment with heat, if your design
allows it. Heating along with the oxidizing solutions can also
sometimes work better than the solutions used cold.