Im sure there may be something already discussed on this one but
anyway. Customer has a large brooch (1.5"di.) made of amber. I
removed it easily from the setting.
I tested - it is amber. Has some chips in it they want “sanded” out
and polished. The amber is a big round cabochon shape with an
intaglio carving on backside. The edges that are under the setting
are chipped and I need to know what to use to sand and polish. What
compound will do this??
Any suggestions??
Thanks-Brent in a big blizzard in Maine.
3000 grit wet/dry sand paper, used with water…VERY lightly. Buff
by rubbing rapidly and with pressure on a piece of flannel or denim.
The process is speeded with the addition of some small amount of
cerium oxide or ZAM. SMALL amount, right on the cloth. Put the
denim/flannel on a table, backed with a folded layer of terry cloth
towel for cushioning and rub away. Works great, low tech.
Amber is easily shaped by sanding. But the “sawdust” gums up, so use
a wet sanding stick. Follow the usual lapidary progression starting
with say 240 or 320 grit, then remove the scratches of this first
stage with 600 or maybe even 800 grit paper (again used wet). Polish
by rubbing the piece vigorously and fairly wet on a clean old cotton
T-shirt with toothpaste, the white type, not the clear gel stuff. If
you need to use mechanical devices (Foredom machine) to get into
concavities, work wet and cautiously at slow speed to minimize heat.
A buff run too hot will “drag” into the surface and may also crack
the piece.
Cheers,
Hans Durstling
post-transcontinental-drive back in Moncton Canada
Brent - To polish the amber, use conventional Tripoli on a loose
cotton buff. Final polish is by hand on clean blue jeans. To shape it
if necessary, use a craytex wheel at low speed. I would not sand it.
A caution about the intaglio carving - any work you do on the back
may affect the carving - and do everything on amber cautiously - it
is really soft and you can really remove amber very fast.