Use of asbestos in jewellery making

Jewelry Discussion
21

Hi Folks,

I’ve been watching this thread for some time now and have
noticed that no one has mentioned the use for many, many years
of the asbestos liner used in casting rings. When the
government banned its use it really played hob with the dental
industry. The coefficients of expansion and contraction of the
investment was predicated to a great degree on the asbestos ring
liner. For dental castings this was the kiss of death! The
castings were all too tight. I well remember the anguish of
that year or so that it took the investment manufacturers to get
it straight. The mineral fiber liner that we now use with the
reformulated investment is super. I suspect that the only
jewelers who had a problem were channel setters.

In dentistry we still have a product called Transite which, I
believe, is an asbestos/concrete formula that is used for bench
tops. We also have a “thingie” (technical dental term) that
looks like 2 1/2" thick slice of a 6" diameter asbestos log with
the inside dished out like a huge dapping block. These are used
for positioning an invested crown or bridge for soldering.
Sometimes you use the ‘cup’ and some times the flat bottom.

Regards,

Skip

Skip Meister
@Skip_Meister
N.R.A. Endowment &
Certified Instructor
in all disciplines
Certified Illinois D.N.R.
Hunter Ed, Instructor

22

Is this the same vermiculite used in gardening? Thanks for the
info (as always!)

All I know about it is found on the top of page 14 in the new
Arrow Springs catalog which reminded me this week of a previous
brief mention in a beadmaking text I can’t put my finger on
tonight. (old timers’s disease?) Georgie

23 
 Is this the same vermiculite used in gardening?   Thanks for
the info (as always!)

You should note that vermiculite is made by strongly heating the
mineral mica. It expands to vermiculite. Mica is NOT asbestos,
and does not pose a danger. Only if the mica is mined in regions
where asbestos also is found, and the mined mica is then
contaminated with asbestos, or if the mica is contaminated with
asbestos in some manner during the heating/manufacturing
operation, would vermiculite contain asbestos. This is, of
course, certainly possible, but is not a forgone conclusion, and
it’s likely that the amounts of asbestos contamination would
probably be fairly low…

Peter Rowe