Lyndi on sat 12 aug 06
I was hoping to get some help on how to use CMC gum solution. I ordered a
pint of liquid gum solution from Columbus Clay. The glaze recipe calls
for 1% gum solution. I have been reading online and am unsure if I need
to add water or if I can just pour what I purchased from Columbus Clay
straight into the glaze. I am also assuming that the 1% would be the
same measurement as everything else, ie. grams? Any help would be
appreciated.
Lynn Goodman Porcelain Pottery on sat 12 aug 06
I always use dry CMC, added to the dry mix, before adding the water.
It's really much easier to figure out the exact amount of gum that way.
I only add wet gum if I feel that I need more gum than I originally
added in, or if the glaze is old (sometimes it seems that the gum gives
out with age). When I do this, I always go by the "feel" of the glaze,
which you would come to know with practice.
Having said that, you can add wet gum to your glaze thusly: Balance out
your scale to zero while it holds the cup that you will be pouring the
gum into; now add the weight of gum (the %) that you will need to the
scale. Add the liquid gum to the cup until it balances again. Add the
measured liquid gum to WET glaze. Don't thin it with additional water!
If you sieved the glaze before adding the gum, you don't need to sieve
it again. You will want your glaze to end up thicker than what you're
used to, as the gum slows down drying time resulting in a thinner coat.
Hope this helps. In the future, you may want to try the dry CMC--it
really is much easier to just measure it out with all your dry
materials.
Lynn
On Aug 12, 2006, at 3:28 PM, Lyndi wrote:
> I was hoping to get some help on how to use CMC gum solution. I
> ordered a
> pint of liquid gum solution from Columbus Clay. The glaze recipe
> calls
> for 1% gum solution. I have been reading online and am unsure if I
> need
> to add water or if I can just pour what I purchased from Columbus Clay
> straight into the glaze. I am also assuming that the 1% would be the
> same measurement as everything else, ie. grams? Any help would be
> appreciated.
>
> _______________________________________________________________________
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>
Lynn Goodman
Fine Porcelain Pottery
548 Court St.
Brooklyn, NY 11231
718-858-6920
Cell 347-526-9805
www.lynngoodmanporcelain.com
Robert W. Anderson on sun 13 aug 06
Lyndi,
Try adding 3-4 teaspoons of cmc to a pint of
water...shake and let stand for a few days. Add
your 1% to the wet glaze and mix. If the glaze
settles, after a few days, add more. Keeping
experimenting.
Bob
From: "Lyndi"
To:
Sent: Saturday, August 12, 2006 2:28 PM
Subject: CMC Gum Solution
> I was hoping to get some help on how to use CMC
gum solution. I ordered a
> pint of liquid gum solution from Columbus Clay.
The glaze recipe calls
> for 1% gum solution. I have been reading
online and am unsure if I need
> to add water or if I can just pour what I
purchased from Columbus Clay
> straight into the glaze. I am also assuming
that the 1% would be the
> same measurement as everything else, ie. grams?
Any help would be
> appreciated.
>
>
__________________________________________________
____________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or
change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be
reached at melpots@pclink.com.
>
>
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Rogier Donker on sun 13 aug 06
Hi Lynne,
Good old Karo syrup (corn syrup) will do the same thing as CMC. Bout
a spoonful to a pint of glaze.
Rogier
See us on the web at http://www.donkerstudio.org
John Rodgers on sun 13 aug 06
Lyndi,
When I work with CMC, it is always dry. The one thing I like to do - and
many others just hate the method - is to work strictly by the numbers. I
definitely do not do the dash of this or pinch of that or teaspoon of
the other. I find that working the numbers works best for me. But that
is my method, easiest for me to track and understand. Others have their
way. But here is mine.
Weigh out a cup of water. Do it exactly, by using a plastic cup and
zeroing the scale with the cup on it it. That is known as setting the
tare. You don't want the weight of the cup in your measurement. Now
weigh a measured cup of water. Record the weight. Now, using the same
plastic cup, weigh a cup of your store-bought CMC mixture. Record the
weight. Take the difference between the water and the CMC. That
difference is the weight of CMC in your store-bought solution. Knowing
the weight of the CMC in the store-bought mix in one cup now enables you
to use a conversion table so you can calculate how much CMC by weight
is in one gram of the CMC mixture. Knowing that makes it simple to
calculate how many grams of store-bought CMC is required for any amount
of dry mix glaze. You calculate your total glaze weight, mix it with
water as you always do, then add the CMC, according to your new
calculations.....one gram, ten grams, forty grams, whatever, of the
store-bought CMC mixture.
If you want to add the CMC mixture to a wet glaze - one already mixed
with water, follow the above procedure and find out the weight of the
solids in the glaze. Then treat the matter as if you were working with
dry glazes just getting ready to mix with water. A certain amount of dry
glaze gets a certain percent of CMC. And since you already have the
numbers on the CMC in solution, . it easy to calculate how many grams of
liquid CMC to add.
And regards using CMC - I use it it principally to bind a glaze for ease
of handling when I have to re glaze a pot. When the Glaze with CMC in it
dries, it can be handled fairly easily, even when applied over an
already fired glaze, because the CMC hardens so. I recently re-glazed
about 40 chalices and 25 plates that had already been glaze fired. They
had blotches in the glaze from the first firing. I sprayed the pieces
with the CMC glaze and they fired perfect. Recovered them all by re
glazing and re firing.
Good luck,
Regards,
John Rodgers
Chelsea, AL
Lyndi wrote:
> I was hoping to get some help on how to use CMC gum solution. I ordered a
> pint of liquid gum solution from Columbus Clay. The glaze recipe calls
> for 1% gum solution. I have been reading online and am unsure if I need
> to add water or if I can just pour what I purchased from Columbus Clay
> straight into the glaze. I am also assuming that the 1% would be the
> same measurement as everything else, ie. grams? Any help would be
> appreciated.
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
>
>
>
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