When I took casting class, we used asbestos sheet to line flasks,
not crucibles. Is that what you were referring to? Now, I believe,
wax sheets replace the asbestos in this application.
Karen
Ron Ramsey
I have been vacuum casting for 30 years and have never used asbestos
in any of my flasks. I have cast small rings to 30 ounces pieces of
pottery. Maybe I am missing something by not using asbestos but I
sure don’t know what. I had a very good friend that died of lung
cancer caused by asbestos. I would sure want to know why someone is
recommending asbestos linings in either the cruicible or flask before
I used
it in my casting.
When I took casting class, we used asbestos sheet to line flasks, not crucibles. Is that what you were referring to? Now, I believe, wax sheets replace the asbestos in this application.
After several years as an aspiring jeweler, I began a second career
as a dental lab technician running a one man lab in a dentist’s
office. The dentist taught me everything that he had learned and I
figured out much of it myself, w/ a lot of time spent on the phone to
Ney, Jelrus, Heareas, etc.
We used to line the flasks. (As a cushion to compensate for the
expansion of the investment-- the so called quartz inversion-- which
would compensate for the innate shrinkage of the cast crown. The
investment expands at a certain temp. and, if the flask is lined,
expands into the soft liner which expands the mold chamber at about
the same % that the casting would shrink, resulting in a perfect fit
of the crown in the mouth. I don’t know if this is still done.)
We also used to line the crucibles. I’m not sure why, but I suspect
that it cut way down on any flux that was present on the metal.
Minute traces of flux might interfere w/ the bonding of porcelain to
a cast coping (armature) in the case of a porcelain on metal crown.
I don’t know if this made any real sense-- I just did what I was
shown.
We used a non asbestos material that was made for this purpose. It
was made from Kaolin, or kaolite , was a fiberous material, and came
as a strip wound in a coil. At that time – the early eighties-- it
was available from dental supply houses.
I don’t use anything, save a flux of boric acid on my clay crucibles
now (as a metalsmith). The aluminum oxide crucibles made by Wesco
are self glazing when brought to a high temp. They are quite
expensive.
Hope that this helps, Andy
For anyone who wants a hair-raising lesson on the dangers of
asbestos, ask Google. Just reading the subject lines of all
available will show it is NOT ok to use - in any form. Please be
IN-formed.
Pat
Hello ok my husband worked for an environmental testing company. they
tested and worked with hazardous materials. there is a lot of scary
blurs out there on asbestos. Asbestos is only proven to be dangerous
when airborne. DO not hammer on it, cut on it or bang it around if you
have it in your work shop. Use a fitted mask with a High Efficiency
Particle Arrestance (HEPA) filter, water keeps fiber from becoming
airborne (watering it down is not 100%, use a HEPA mask too). a HEPA
filter should be used in any studio, asbestos free or not.
There are more deaths and injuries a year from falls (and smoking)
than asbestos contact. the people who are in the most danger are
workers who made asbestos products and lived near factories, most
construction workers, plumbers and currently auto mechanics. that
said there is no reason to take any risks. Wear a HEPA or remove the
work pads and sheets if you have any and feel uncomfortable but don’t
just throw it away. it needs to be bagged and sealed. Blocks are
safer.
If you think that removing it from you studio means you are asbestos
free, you are not. everyone is exposed to it. Low levels of asbestos
can be detected in almost any air sample. whether you live in the
city or country.
It is still used in many cars. if you have brake linings and other
parts made before 2000. chances are that they are asbestos. his
company tested used brake linings out of every ten and average of 7
were asbestos. After 2000 it dropped but parts are still not asbestos
free. there is asbestos in most of the Us drinking water because of
the pipes, although drink asbestos is not proven to be dangerous.
airborne asbestos is. there is asbestos in many textiles (
clothing,blankets,etc). there is asbestos in many ceiling and floor
tiles. that is not all, you think there was a ban on asbestos? think
again
In 1989, EPA banned all asbestos products. Two years later the
Canadian and U.S. asbestos industry sued EPA in federal court and
succeeded in getting the ban thrown out. asbestos only have has to be
removed if there is construction, or the asbestos is damaged. Because,
the EPA and private testing has proven that sealing is is safer than
removing it.
The most dangerous site other than your garage? road work. Not
kidding. If they are working on underground pipes in your neiborhood
or digging up road near pipes they are blanketing the air with the
stuff. In ny they test the air quality before, during, and after
construction. my husband and his co-works had no problem soldering on
a hard asbestos block (much less likely to become airborne) but stay
away from heavy construction.
ok the post is kind of long,but i figured the is
important.
~Carolena