JuanitaBlu@AOL.COM on wed 3 oct 01
James Chappell suggests in his book of clays and glazes that CMC should be
mixed with a few drops of formaldehyde to deter spoilage. Is this really
necessary, and, if so, can any clayarters tell me where to find formaldehyde?
Thanks, Juanita Blumberg, Blue Hill, Maine
Des Howard on thu 4 oct 01
Juanita
Before the anti-formaldehyders start doomsaying.
A few drops of formaldehyde aka formalin will stop greeblies forming in gum acacia,
gum tragacanth & flour pastes.
I can't see why one would add it to a CMC (carboxymethylcellulose) gum tho'.
We make up 4 litre batches of CMC gum at a time & have never had spoilage, even
during very warm weather.
Formaldehyde can be bought from our local pharmacy.
Des
ps The CMC gum powder we use is bought from a local
farm supply company as a pelleting adhesive,
it is used for coating legume seed with limestone
& nitrogen fixing bacteria.
Cheap & effective.
D
JuanitaBlu@AOL.COM wrote:
> James Chappell suggests in his book of clays and glazes that CMC should be
> mixed with a few drops of formaldehyde to deter spoilage. Is this really
> necessary, and, if so, can any clayarters tell me where to find formaldehyde?
>
> Thanks, Juanita Blumberg, Blue Hill, Maine
>
> _--
Des & Jan Howard
Lue Pottery
LUE NSW 2850
Australia
Ph/Fax 02 6373 6419
http://www.luepottery.hwy.com.au
Wade Blocker on thu 4 oct 01
Juanita,
I have a plastic bottle filled with CMC mix. Since I rarely use CMC the
mix is probably a year old. It has no odor, therefore no spoilage. Cannot
see why formaldehyde is necessary. Mia in ABQ
The Allens on sat 6 oct 01
I have found that a little chlorine bleach will prevent spoilage and it =
doesn't smell like a high school biology project. (The frogs and cats =
never bothered me but the formaldehyde did!)
Carla Allen
callen@caveland.net
Dave Finkelnburg on tue 9 oct 01
Hello all!
I realize I am coming to this post rather late. I've found it among the
600+ posts waiting for me when I got home!
I use CMC in some glazes, and have some glazes, not all, though, which
get very, very smelly. I have always associated the smell with CMC being
decomposed by bacteria, but that may be a hasty assumption. I have never
tested this theory. I do have to admit that when I mixed pure CMC and
water, I didn't have a problem. On the other hand, a strong solution of
sugar is a medium in which bacteria doesn't grow. If you don't believe it
look at fruit preserved in sugar! Maybe a strong CMC solution won't grow
bacteria well.
Does anyone have any factual information on the subject? Has anyone
tested a solution of approximately 1/2-percent CMC in water, to see if it
will support the growth of bacteria?
Dave Finkelnburg, wondering if he's wrongly accused CMC gum
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