Paul Herman on mon 18 apr 11
Greetings All,
How should I use this stuff? It's called CMC powder and I think it's
needed in a couple of my glazes, which are very soft and easily rubbed
off in the dry state. It will make the dry glaze coat more durable, I
understand.
I took 5 grams and soaked it in a half a cup of water and it turned
into a gelatinous mass that I'm not sure I want to put into my glaze.
How do any of you use CMC?
Thanks in advance,
Paul Herman
Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/
William & Susan Schran User on mon 18 apr 11
On 4/18/11 8:04 PM, "Paul Herman" wrote:
>
> How should I use this stuff? It's called CMC powder and I think it's
> needed in a couple of my glazes, which are very soft and easily rubbed
> off in the dry state. It will make the dry glaze coat more durable, I
> understand.
> I took 5 grams and soaked it in a half a cup of water and it turned
> into a gelatinous mass that I'm not sure I want to put into my glaze.
> How do any of you use CMC?
Paul, just add more water and shake up.to the consistency you want.
I use a CMC solution with all of my crystalline glazes.
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
Snail Scott on tue 19 apr 11
On Apr 18, 2011, at 7:04 PM, Paul Herman wrote:
> How do any of you use CMC?
I add it as a powder during the initial mix. It will
swell up and become little gelatinous beads,
but an overnight soak and re-mix (which I do
anyway) cures that problem.
Some people do premix it and add the jelly to a
mixed glaze; it amounts to the same thing without
the overnight wait. I just prefer to store it as a powder.
-Snail
Lynn Goodman Porcelain Pottery on tue 19 apr 11
I add it as a percentage into the dry mix (anywhere from .25% to 2%,
depending on why you're using it); mix through with your hand to
disperse it,then add water and sieve as usual. However, I add LESS
WATER than I normally would because the CMC will delay drying, so you
get a thinner coat.
Lynn
> On Apr 18, 2011, at 7:04 PM, Paul Herman wrote:
>> How do any of you use CMC?
Lynn Goodman Porcelain
Cell 347-526-9805
www.lynngoodmanporcelain.com
Des & Jan Howard on tue 19 apr 11
Paul
I make 6 litre batches (3 x 2 litre juice containers).
90 gms CMC powder.
add to 1200 ml hot water.
disperse powder.
add 4800 ml cold water.
place under column stirrer until nice & thick syrupy.
add good slurp disinfectant (doesn't go rotten like
various gums, just loses efficacy).
add 30 ml of syrup to 1 litre glaze slop.
Des
On 19/04/2011 10:04 AM, Paul Herman wrote:
> How should I use this stuff? It's called CMC powder and
> I think it's
> needed in a couple of my glazes, which are very soft
> and easily rubbed
> off in the dry state. It will make the dry glaze coat
> more durable,
--
Des & Jan Howard
Lue Pottery
Lue NSW
Australia
2850
02 6373 6419
www.luepottery.hwy.com.au
-32.656072 149.840624
Stephani Stephenson on wed 20 apr 11
Paul
when i used it I did much like you did. I added recomended amount, usual=
=3D
ly
1% or less, to hot water .=3D20
stir or let it set to dissolve, then combine that water with the other
drymixed ingredients.
if it is too gelatainous, just add more water..if it seems like an awful
lot, maybe you are adding too much percentage wise for your batch..hard =
=3D
to
say from here.
one time i experimented by painting a thin layer of CMC in between a glaz=
=3D
e
basecoat and some overglazes. i wanted to see if it would act as a
hardener/isolation coating between the two... when i pulled the test bars=
=3D
out of the kiln, the cmc had caused a blackened, blistering mess..evident=
=3D
ly
it had been unable to burn out.=3D20
but i have never experience such a thing when mixing it in small % in the=
=3D
glaze.
Des & Jan Howard on wed 20 apr 11
Stephani
That must have been one thick "thin" layer.
We use our CMC gum syrup as a trail, brush or foam pad
layer under glazes. It does a semi resist, thins the
next layer of glaze instead of repelling it, as wax
does. The gum disappears in the firing.
Des
On 20/04/2011 2:36 PM, Stephani Stephenson wrote:
> one time i experimented by painting a thin layer of CMC in between a glaz=
e
> basecoat and some overglazes. i wanted to see if it would act as a
> hardener/isolation coating between the two... when i pulled the test bars
> out of the kiln, the cmc had caused a blackened, blistering mess..evident=
ly
> it had been unable to burn out.
> but i have never experience such a thing when mixing it in small % in the=
glaze.
--
Des & Jan Howard
Lue Pottery
Lue NSW
Australia
2850
02 6373 6419
www.luepottery.hwy.com.au
-32.656072 149.840624
Paul Herman on wed 20 apr 11
Thanks,
To all who responded to my questions about CMC. I've got a much better
idea where to start now.
I'll try it in the blue celadon, which is low in clay and has some
wood ash in it, and an iron red that tends to get red smudges on
everything.
best wishes,
Paul Herman
Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/
On Apr 19, 2011, at 9:36 PM, Stephani Stephenson wrote:
> Paul
> when i used it I did much like you did. I added recomended amount,
> usually
> 1% or less, to hot water .
> stir or let it set to dissolve, then combine that water with the other
> drymixed ingredients.
>
> if it is too gelatainous, just add more water..if it seems like an
> awful
> lot, maybe you are adding too much percentage wise for your
> batch..hard to
> say from here.
>
> one time i experimented by painting a thin layer of CMC in between a
> glaze
> basecoat and some overglazes. i wanted to see if it would act as a
> hardener/isolation coating between the two... when i pulled the test
> bars
> out of the kiln, the cmc had caused a blackened, blistering
> mess..evidently
> it had been unable to burn out.
> but i have never experience such a thing when mixing it in small %
> in the glaze.
Bonnie Staffel on thu 21 apr 11
Paul, I use the CMC powder all the time and it works great to keep the
powdering of the glaze stable.=3D20
=3D20
I weigh out 1/2 of 1 percent of the total weight of the glaze =3D
ingredients
and choose one of the dry ingredients to mix it in, say Kaolin. I then =3D
use
very hot water in which to dump the dry glaze ingredients, let it soak
overnight and then screen your batch as you would ordinary glazes. It =3D
does
tend to flocculate =3D3D-deflocculate your glaze so you do not need the =3D
amount
of water as without CMC. So I use the least amount and then check it =3D
with
the hydrometer to the number that works best for your bisque. Mine is =3D
1.7. I
believe that you will find that the feldspars will not sink to the =3D
bottom as
a hard cake either. Takes very little stirring between dips when =3D
glazing.=3D20
=3D20
Since I decorate my pots on top of the base glaze, it gives me a hard
surface while still absorbing the colors of Mason stains or oxides.=3D20
=3D20
Any questions, please write.
=3D20
Bonnie
http://webpages.charter.net/bstaffel/
http://vasefinder.com/bstaffelgallery1.html
DVD Throwing with Coils and Slabs
DVD Introduction to Wheel Work
Charter Member Potters Council
=3D20
Bonnie Staffel on thu 21 apr 11
Coops!!!! Correction!!! Sorry, but I meant to say 1/4 of 1 percent is =3D
the
ratio. I have found that adding the syrup is more difficult to be =3D
weighed in
relation to the total glaze. In using my formula, the glaze will always =3D
have
the same gum ratio.
=3D20
Bonnie
http://webpages.charter.net/bstaffel/
http://vasefinder.com/bstaffelgallery1.html
DVD Throwing with Coils and Slabs
DVD Introduction to Wheel Work
Charter Member Potters Council
=3D20
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