I'm new here and new to working with stones. I cut, shaped, and
polished a piece of lapis into a bear fetish. I then wire wrapped
it but its far to busy! So, I would like to try to carve out my
designs on it and inlay with silver or perhaps enamel or resin.
Where can I go to find out if the stone will withstand the heating
process for enameling?
While Lapis might not explode or something upon such heating, it
won’t survive enamelling temperatures well. Many years ago (40
something) I cast in place a Lapis cabochon into a silver ring. This
worked, but the Lapis’s outer half millimeter turned a dull grey
crappy color. Since it was intended as a flush “inlay” look, I was
able to repolish the whole surface, Lapis and silver both, to get
back to Lapis inside, with just a thin line of the junky color
showing. But that might not always be your experience, especially
since enamelling goes hotter than that burnout did. In general, I’d
not expect Lapis to survive enamelling. In fact, for the most part,
you’re best off not expecting most stones to survive that process.
There are a few, like synthetic ruby and sapphire or the synthetic
spinels, and maybe even some of the garnets (if you’re lucky) that
could survive this. But most stones will either not do so well, or
will be risky. Enamelling entails a fairly quick heat up and cool
down rate, and few stones are happy with that other than diamond, and
diamond needs protection from oxygen at such temps and doesn’t much
like the 1500 degrees you might need for enamelling either. (a bit
too hot even for diamond, to work safely.)
If you wish to enamel on stones or pieces with stones, you’re best
off either enamelling the piece before the stones are set, or using
the resin low temperature materials designed to look like enamel,
such as Ceramit or Ceramitation (polyester resin based) or Colores
(epoxy based) or similar. These cure at temps under 200 F., which
most stones other than things like pearls, amber, or turqoise, etc,
will withstand just fine. Lapis would have not problem with that
temperature, and the resins would bond to the Lapis just fine.
Or even if I can carve it out like I want to do. I do have a
foredom drill but don't have any burs or such. Can anyone tell me
what kind of burs I need to work with stone?
For the most part, you want diamond burs. These have a diamond
abrasive bonded to the working end of the bur with a nickle
electroplate, or with better quality ones, a working end that is
solid sintered diamond and metal (lasts longer). Often this type of
bur is sold specifically for lapidary work, or for dental work. On
very soft materials such as pearl, amber, Malechite, etc, you can do
some limited carving with steel burs, but they’ll tend to dull
quickly. Carbide burs will last longer, but their teeth are not
really designed to work well with hard/brittle materials. Grinding
tools, such as those with an abrasive end, or things like seperating
disks, will work well. You can make your own lapidary carving burs
from soft metal like copper or brass or bronze, and charge them with
loose abrasive grit, usually silicon carbide or aluminum oxide or
diamond, usually applied as a wet slurry. Cheap, you can get whatever
shape of bur you might need if you can make it yourself, but it gets
messy working this way, and is slower than diamond burs.
Will the dremel tool burs I have work with the foredom?
Yes. Some, like diamond burs or some abrasives work best at fairly
high speeds, so for some, the dremel tool actually works better,
since most of the dremels have a top speed above that of most foredom
tools. The disadvantage to the dremels is that with this type of
work, you’re often working with water as a lubricant and coolant, and
the dremel is an electric motor right in your hand. Even with double
insulated well made dremels, this is slightly riskier (even if only
to the tool) than working with a flex shaft like the foredom, where
the working end is a long way from the electric stuff.
Hope that helps.