Chris Trabka on wed 29 nov 06
A good piece of information about what CMC can and can not do has been
presented by P. Pinnell in the 1998 March/April and May/June issues of Clay
Times. The articles are available on line at:
http://www.claytimes.com/articles_glazeadjusting.html
Note that this article states CMC can be used as a deflocculant (make a
glaze settle like a rock) - and I have witnessed CMC do just that.
Chris
Bonnie Staffel on thu 30 nov 06
I use CMC as a gum for many things and for one, it keeps my glaze =
floating
to the point I hardly have to stir at all between dipping each pot. The
glaze does dry to a "rock" on the bisque so that it can be handled =
without
powdering. I can paint on the surface and the material is absorbed and
dries right away giving me a non-smearing decoration as I have also put =
a
grain or two in the stain as well. My CMC does not result in a moldy =
mess
either. I make up a big vat of glaze that I use over a course of months =
and
it has never molded. Perhaps I have the kind that doesn't degrade into =
mold
as there are several available to the ceramic industry as well as the =
food
industry. I have had my can of CMC for so long that I have no idea of =
the
origin and don't even remember where or when I purchased it. I might =
add
that I have been using CMC for at least 30 years or more. =20
>Chris wrote: Note that this article states CMC can be used as a
deflocculant (make a glaze >settle like a rock) - and I have witnessed =
CMC
do just that.
Bonnie Staffel
http://webpages.charter.net/bstaffel/
http://vasefinder.com/bstaffelgallery1.html
DVD Throwing with Coils and Slabs
DVD Beginning Processes
Charter Member Potters Council
Barbara Lewis on thu 30 nov 06
Hi Bonnie: How do you add it to the glaze? With the dry ingredients or do
you dissolve it and then add to the wet . . .? I have a celadon glaze that
settles like a rock and this sounds like it could be a solution. Thanks,
Barbara
----- Original Message -----
From: "Bonnie Staffel"
To:
Sent: Thursday, November 30, 2006 7:13 AM
Subject: what is CMC used for?
I use CMC as a gum for many things and for one, it keeps my glaze floating
to the point I hardly have to stir at all between dipping each pot. The
glaze does dry to a "rock" on the bisque so that it can be handled without
powdering. I can paint on the surface and the material is absorbed and
dries right away giving me a non-smearing decoration as I have also put a
grain or two in the stain as well. My CMC does not result in a moldy mess
either. I make up a big vat of glaze that I use over a course of months and
it has never molded. Perhaps I have the kind that doesn't degrade into mold
as there are several available to the ceramic industry as well as the food
industry. I have had my can of CMC for so long that I have no idea of the
origin and don't even remember where or when I purchased it. I might add
that I have been using CMC for at least 30 years or more.
>Chris wrote: Note that this article states CMC can be used as a
deflocculant (make a glaze >settle like a rock) - and I have witnessed CMC
do just that.
Bonnie Staffel
http://webpages.charter.net/bstaffel/
http://vasefinder.com/bstaffelgallery1.html
DVD Throwing with Coils and Slabs
DVD Beginning Processes
Charter Member Potters Council
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Steve Mills on fri 1 dec 06
I use CMC (with a bactericide) to make a local stone slurry workable as a
glaze without adding anything else.
Steve
Please note my new email address:
steve@mudslinger.me.uk
NOTE. anything other than "steve" before the @ won't get through!
Steve Mills
Bath
UK
Bonnie Staffel on fri 1 dec 06
Barbara, I weigh out the amount of .0025 percent or 1/4 of 1% CMC to the
total weight of the glaze materials. I dry mix it in with one of the
materials and add all ingredients to hot water. Dry materials seem to =
slake
more quickly in hot water. I then screen it a couple of times through =
an 80
mesh screen. It is also good to let it all stand overnight. I think I
also add 2% bentonite, also mixed dry in one of the ingredients. Then =
don't
use too much water. Just soak in a minimal amount of water until all =
dry
ingredients are saturated. I take a reading of 16 or 17 with my glaze
formula and my bisque absorption after screening. Yours may be =
different.
Have some bisque shards and test dip and pin scratch to see if the =
thickness
is correct. It will be hard to remove too much water as it really =
floats
the materials for a long time, at least it does my glaze.
Let me know if this answers your question.
Bonnie
http://webpages.charter.net/bstaffel/
http://vasefinder.com/bstaffelgallery1.html
DVD Throwing with Coils and Slabs
DVD Beginning Processes
Charter Member Potters Council
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