I finally purchased my kiln last week(Paragon SC3) and got some
dedicated wiring setup in my garage. That’s when I started realizing
that I needed a whole whack of items. Kiln shelves, posts, and
Alumina hydrate for holding odd PMC items, etc. Everywhere I look
people are saying to use alumina hydrate. Since I have none and
wanted to fire a batch of charms in the kiln I decided to use satin
cast in dry form, dumping on a mound of it and placed my items on
top. Low and behold, it worked very well. Thought I would share this
bit of info and see if anyone else has had success/failure using
investment instead of alumina hydrate.
Thought I would share this bit of info and see if anyone else
has had success/failure using investment instead of alumina
I haven’t used investment-- I use silica sand. Works just fine, and
has the advantage that the particles are big, so there’s no dust to
breath in. You can use anything that won’t burn or melt at the temps
you’re working with. Silica sand is neat and doesn’t fly around or
stick to things, so you can reuse it indefinately, though it turns
yellow from something in the PMC.
top. Low and behold, it worked very well. Thought I would
share this bit of info and see if anyone else has had
success/failure using investment instead of alumina hydrate.
Jonathan Brunet Montreal
Jonathan I have worked more with PMC sheet then PMC but have found
vermiculite (found at any garden store) to work very well with out
so much dust. Oh ya it is cheap too.
Never, Ever use satin cast in your kiln in the powder form.
Thankfully Orchid members are kind enough to point out problems. So I
threw out the ceramic fiber shelf which was used. I want to think
that the amount of satincast used on the shelf was minimal but, as was
pointed out by Phillip from Rio, the damage may be done. Lets hope
the universe aligns itself in my favor. If I understand correctly,
the investment particles will dislodge from the kiln walls and attach
to enamel or glass projects? The idea to use dry investment in the
kiln came from a brief article about heat-treating mined Tanzanite.
It said to put the carved stones in the kiln surrounded by dry
investment for insulation. Could someone assure me that a one time
error won’t cost me a 200$ ceramic fiber/element repair job.
You can buy a great kiln shelf kit from Chris Darway of PMC Tool and
Supply (Rio now carries most of his products), it’s three shelves
with a hole in the center, a bunch of posts/risers. I would also
recommend his ring sagger kit and PMC Extender, while you’re
You can now buy the entire back issue set of the newsletter, Studio
PMC, for $15.00 (non-members). Go to www.PMCGuild.com.
On the alternative to alumina hydrate, you can use garden variety
vermiculite, from the gardening store. Works great, isn’t
If your items are flat on the back, just put them directly on the
Chicago area, Illinois, USA
Certified PMC Instructor
Dear Orchid, I usually sit by the way side and observe this wonderful
forum. I also answer many posts directly but this time I feel that I
do need to step up to the plate on this one. Never, Ever use satin
cast in your kiln in the powder form. There are several reasons that
come to mind. This product should only be used as directed. Some
of the reasons are as follows:
The dust can cause silicosis or lung cancer. (This is a bad
You can not get all of the dust out of your kiln. Because of
this, you most likely will never be able to do any kind of enameling
or glass work in the kiln. The dust never goes away.
If you “dumped” a pile of the powder in the middle of your kiln
floor, you can get hot spots and clog the pores of the fiber in the
There are reasons that certain items are recommended for use with
PMC. First and foremost, for your safety, but also to make sure you
get a long life out of your equipment.
This IS NOT A SAFE practice and should be discouraged.
Technical Support & Sales
Hello Jon, I use vermiculite from the garden shop instead of alumina
hydrate. Have fun, Judy in Kansas
Judy M. Willingham, R.S.
Biological and Agricultural Engineering
237 Seaton Hall
Kansas State University
Manhattan KS 66506
Jon - We have used both alumina hydrate and investment. It seems to
make no difference in the firing of the PMC. I think the earlier
books (that came with the PMC) indicated that you could use dry
investment rather that alumina hydrate.
Use extreme caution in substituting vermiculite for the alumina
hydrate. There are some areas/brands of vermiculite that contain
trace amounts of asbestos – and everyone certainly does not want to
fire that up and breath the results.