Can molten metal be poured to achieve the inlay?
Sure, you can pour it. But it won’t adhere to your ceramic,
and will possible crack it from heat shock.
How would we shield the raised part to keep it from being
covered with the metal? I
Probably wouldn’t have to. Metal is heavy. Pour it over a
relief, and so long as it stays molten long enough, it will flow
to the low spots, and off the high spots.
But this is acadmic. Don’t do it with poured metals.
Just contact your glaze suppliers. They can sell you several
types of low fire glazes that are made with various metalic
salts, which when fired in the last low fire stage of production,
and applied generally over a previous coat of a decent vitreous
glaze (rather than the raw bisque ware), will fire to a bright
metalic finish. They look just like metal when fired. You can
get platinum, gold, and copper, that I’ve seen, and probably
variations of these colors too. If I recall correctly, these are
called luster glazes, and are fired appreciably lower than the
temps used for normal vitreous glazes. You can apply them the
same way, brush, spray, etc. Your same shielding techniques
should work, as they are still a liquid. I think the carriers
are often oil based, though, so you’d need a masking material
that will repel the oil carier for the luster glaze. While these
materials are not cheap, they would still be less expensive, I’d
guess, than actually pouring metals into your relief.
The other method I’d say might be worthy of consideration is
electroplating. You can coat a surface to be electrically
conductive, and then electroplate it. While better suited to
designs where the metal is on the raised portions, instead of
down in the relief, it can still be done. the cost of
electroplating itself may be less than the cost of some of the
luster glazes, but because it’s a whole new process for you, I’d
guess it’s less practical. You’ve already got all the equipment
you need to use the luster glazes. contact a commercial
electroplating firm for better advice on how to do what you want
with electroplating, and I’d suggest using an outside firm, at
least until it becomes clear you’re going to be doing the kind of
volume that warrants setting up your own equipment. While simple
jewelry level electroplating of small items can be done in a
small beaker on a table top for minimal cost, the type of object
and volume your talking about is likely to be a good deal more
invovled, especially since the items require the additional step
of making the surface conductive. But with these items, you might
simply be able to dip the whole thing in the conductive lacquor,
and then just wipe it off the high spots… it would only plate
where there remains a good solid coating, residues of the paint
could be washed off later…
Hope this helps.