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glaze drying slow and cracking

updated sun 20 feb 00

 

J.B.Coleman@elsevier.com on thu 17 feb 00

After many years of glazing and firing at a community studio, I built a
small studio and am in the process of glaze testing. I started out with
recipies used by the community studio, but I am having a problem with a few
of the glazes drying slowing and then cracking and not sticking to the pots.
I tried adding CMC and epson salts, but that did not resolve the problem.
Could the cracking occur from bisquing to the wrong temperature or having
too thin glaze? I am using cone 8 stoneware and bisqued to cone 05.

Thanks for any help anyone can provide.

Janet
j.b.coleman@elsevier.com

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Chris Schafale on fri 18 feb 00

Hi Janet,

Would you mind sharing the recipes for the glazes that are
cracking? This might help narrow down the problem.

Chris

> ----------------------------Original message----------------------------
> After many years of glazing and firing at a community studio, I built a
> small studio and am in the process of glaze testing. I started out with
> recipies used by the community studio, but I am having a problem with a few
> of the glazes drying slowing and then cracking and not sticking to the pots.
> I tried adding CMC and epson salts, but that did not resolve the problem.
> Could the cracking occur from bisquing to the wrong temperature or having
> too thin glaze? I am using cone 8 stoneware and bisqued to cone 05.
>
> Thanks for any help anyone can provide.
>
> Janet
> j.b.coleman@elsevier.com
>
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> `
> end
>


Light One Candle Pottery
Fuquay-Varina, NC
candle@intrex.net
http://www.angelfire.com/nc2/candle (work in progress)

Judith Enright on fri 18 feb 00

Janet -- could be lots of things, including a too-thick application
of the glaze. You could try wetting the pot down a skosh, either
with a quick rinse and allow to dry for a few moments, or just
spraying it with a spritzer bottle of water, wait a moment or two,
then dip into glaze.
The Enrights!
at enrights@ricochet.net

Jim Brooks on fri 18 feb 00

Janet, you can add up to 2.% bentonite to your glaze without changing the
color...most of the time.. try adding 1%, mix, and use.. if the problem
presist, add another .5% and try again,. Bentonite usually will solve the
problem you dscribe.

Paul Taylor on sat 19 feb 00

Dear Janet
You did not give the glaze recipe so my comments are speculative.

The only time this happens to me is if I glaze the pot too thick and or
there is too much ash in the glaze and or I have made the pot too wet and
the glaze refuses to dry instantly .

There is a tendency for amateurs to leave the pot in the glaze.
Professional potters find themselves very quickly taking the pot out as soon
as it is covered -Time being money, and make the discovery that leaving the
glaze in to the count of x + was one of those myths that circulate around
part time courses.

If the biscuit is fired to high thus too soaked with glaze. The glaze
will peel, especially if there is a lot of clay in the glaze . It prefers to
stick to it's viscous self than the pot.

If you need a thick glaze do not flocculate the glaze or hold it in the
glaze longer because the glaze will tend to hold more water; but add more
powder to the slop. The glaze thickness should inhibit the glaze settling
but you will still have problems with settling- so keep stirring.

The best potters know that sharing their glazes pose little threat to
them, and by doing so they are Joining the heroes of the pottery movement
like Hammada and leach, who broke with the tradition of secrecy and
published. It is their example that breathed new life into a dying craft
movement and this list is part of that new tradition. I expect there are
reasons that you did not give the glaze recipe. May be you have confidences
to keep or did you not realize that some in this group can fix a faulty
glaze very efficiently.

Regards Paul T

ps personal replies to tamblin@go.com as well as ANU. People have been
having trouble with the latter.
----------

----------
>From: J.B.Coleman@elsevier.com
>To: CLAYART@LSV.UKY.EDU
>Subject: glaze drying slow and cracking
>Date: Thu, Feb 17, 2000, 9:24 pm
>

>
>D----------------------------Original message----------------------------
>After many years of glazing and firing at a community studio, I built a
>small studio and am in the process of glaze testing. I started out with
>recipies used by the community studio, but I am having a problem with a few
>of the glazes drying slowing and then cracking and not sticking to the pots.
>I tried adding CMC and epson salts, but that did not resolve the problem.
>Could the cracking occur from bisquing to the wrong temperature or having
>too thin glaze? I am using cone 8 stoneware and bisqued to cone 05.
>
>Thanks for any help anyone can provide.
>
>Janet
>j.b.coleman@elsevier.com
>