I’m wondering if anyone can point me in the right direction. I take
a lost wax casting jewelry class and we use asbestos sheets (kinda
like paper towels but thicker) to line our crucibles with. My
teacher is running low and was wondering where she might find
somemore of this or a safer replacement. She got some stuff that was
some type of spun fiber, but it just makes a mess of everything when
melting the metal, getting little fiber bits in it. The liner from a
soldering pan would work, but we can’t find anyone who can tell us
where to get that either. Help!
Furnaces for melting metals and ceramics are often insulated with
ceramic fiber materials. The one I’m familiar with is Fiberfrax.
The website shows a lot of different products - maybe one will work.
Wendy, I do not know a source for asbestos sheets except maybe
unwind the inards of a wound soldering block available from most any
jeweler supplier. But I have a question for you - or rather for your
teacher. I have been casting for around 25 years and have never used
asbestos or other liner in my crucibles! Why do you? I use a
seperate crucible for each metal and give it a good lining of borax
with creates an excellent glass like surface. If you periodically
flux the crucible it should last a very long time. I have read in
some casting books about using asbestos but never quite understood
why except maybe to preserve the crucible. In my opinion, the
asbestos could become uneven and cause turblance when the metal is
injected. It could also burn away and produce unwanted ash that may
be carried into the pattern chamber.
Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry! @coralnut1
I'm wondering if anyone can point me in the right direction.
I take a lost wax casting jewelry class and we use asbestos sheets
(kinda like paper towels but thicker) to line our crucibles with.
My teacher is running low and was wondering where she might find
somemore of this or a safer replacement.
A borax and boric acid coating has served me well so far for coating
and cleaning, what composition are your crucibles?
Asbestos is not the best way to go for anything, it is dangerous and
the ash that might be produced contains fibers which if inhaled or
ingested can cause asbestosis, which is similar to the black lung
disease found in some coal miners and silicosis found in miners from
gold, silver, copper, lead and zinc mines.
Wendy, get “non-asbestos ribbon” made by GC ( a Japanese dental
products manufacturer. Any U.S. company selling the GC products e.g.
waxes. sprues, etc. would probably stock it. If you are not
successful, write me off line and I will introduce you to a Japanese
firm that can supply you with it.
I feel I really should chip in here. I am surprised that no-one has
mentioned the possible dangers associated with asbestos. Is this not
an issue in America? Have the Australians possibly gone too far in
their fear of the dangers of breathing in asbestos fibres? Has there
been a climate of fear built around asbestos here and the dangers of
contracting mesothelioma?
Don’t want to scare anyone, but if you say “asbestos” in Australia,
someone else says Aaaaarrgghh!
I’m very fond of you clever Orchideans (and those just learning) and
would hate you to subject yourselves to danger. On the other hand I
am aware of the possibility of being manipulated by the result of a
one or two emotive stories in the media and the rest of the
population becoming paranoid.
I would be interested in your opinions on this subject, as I have
put sheet asbestos to good use in the past and sometimes wish I
could find something to do the same job that is not so dangerous.
Regarding asbestos sheets. Are you lining your crucible or your
flask? I am a lurking dentist. In dentistry we line our flasks prior
to investing with strips of thickish asbestos prior to investing. As
memory serves this is to lessen the shrinkage in the cast crown or
bridge. I have never used this in casting any jewelry. It was a must
in dental school. I am sure that dental lab supply houses such as
Kerr have this or a non asbestos substitute. I believe anyone with a
wholesale number will be able to purchase from them. In lieu of that
you may find a friendly dental lab that can help. Also try the
dental supply houses in the phone book. In regards to burnishers. We
dentists use these in all shapes and sizes. If you can access a
dental catalog they will be listed under "operative dental
instruments"
Hope this helps, Mary.
In dentistry we line our flasks prior to investing with strips
of thickish asbestos prior to investing. As memory serves this is to
lessen the shrinkage in the cast crown or bridge. I have never used
this in casting any jewelry. It was a must in dental school.
It’s not so much that the lining itself lessens the shrinkage of the
casting, its that you’re using high expansion investments (often,
crystobalite based, for golds, others for higher temp metals).
These investments expand more on heating than the normal jewelery
investments, and are intended so that the expansion, which makes the
mold cavity larger than the original wax model, then equals the
amount of contraction the casting will experience as it cools, so
that the finished casting is the same size as the wax. The high
expansion investments can either distort a casting flask, or if not
that, crack from the stresses, if the flasks are not lined. These
dental investments, while not commonly used by jewelers due to
higher cost and a bit more complexity in the investing process (the
lining, among other things), are still good for jewelers to keep in
mind, for those occasional casting tasks where this same exact match
of wax size to casting size is needed, such as some types of inlays,
and the like. Jewelers should note that the expansion of the
investment is not automatically right for your metal. You have to
match the thermal characteristics of your alloy, to those of the
investment. Calibration amounts to determing the correct flask
temperature for casting, which is then chosen as much to decide the
temperature of the flask when the metal solidifies, as anything else.
this of course, complcates the usual determinants for flask
temperature, that being casting quality and porosity, etc.
am surprised that no-one has mentioned the possible dangers
associated with asbestos. Is this not an issue in America?
Indeed it is an issue in America. Asbestos removal has become a big
business here in the States since the public learned the health
consequences of exposure to asbestos fibers . Looking through my
jewelry supply catalogs I see that none of them carry asbestos
soldering pads any more., but have gone to other materials,
including high-heat ceramic. Truthfully, I was surprised to see that
people were still using asbestos, considering the risks.
Dee
I am a lurking dentist. In dentistry we line our flasks prior to
investing with strips of thickish asbestos prior to investing
Hi Mary nice to meet a fellow dentist who is also involved in
metalsmithing. I used to correspond with Skip Meister who has
recently passed away but who left his mark on this wonderful forum.
He was a very well informed dental technician but was also involved
with jewelry and frequently contributed most useful to
Orchid.
As to asbestos: we would line the inside of casting flasks to permit
the expansion of the investment during burnout so as to partially
compensate for the shrinkage of the gold which took place when gold
went from the liquidus state to solid state. It (lining) also made
for easier cleanout of the casting rings (flasks). This procedure
was modified in the late '70’s when we all became aware of the
potential danger of asbestos inhalation and a substitute liner was
supplied with the purchase of investment material. The asbestos
strips were used by some to line the crucible in the casting
machine, but this is easily accomplished with a layer of casting
flux melted onto the surface of the crucible. Joe Dule