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rehydrating old glazes

updated thu 20 apr 06

 

C. A. Sanger on tue 18 apr 06


I am back in the studio a few hours a day after several years of illness.=
I have 8 buckets of cone 10 reduction glazes that have sat unopened all=
that time in 5 gallon buckets with lids. Some dried out completely, oth=
ers have minimal water sitting on the surface. I figured the dried ones =
could be repowdered, and I could do a simple ratio of the initial water t=
o powder content to the current powder to know what water to add. The w=
et ones are my problem. I do not know the viscosity, having not gotten a=
round to testing that prior to getting ill. I could rehydrate "by eye," =
but wondered if there is a mathematical method I am ignorant of. Althoug=
h I know the initial weight of the powder and water used to mix all, the =
glazes had been used so some glaze and water was gone. Also, should I to=
ss the Shino? It had the usual soluables in it. The other glazes includ=
e whites, clear, celadon, Touch of Moon, a non-foodsafe turquoise. If it=
would be "better" to toss the lot, it wouldn't be a total tragedy to me.=
I am about to initiate a large glaze development and testing program, u=
sing John and Roy's great book, and Currie's grid system. I had been hav=
ing fit problems with the celadon and clear glazes, which I now know are =
due to COE conflicts with the clay body. Thanks to all more knowledgable=
members for your kind help. C. A. Sanger

C. A. Sanger ShardRock Clay Studio Herington, KS 67449

katetiler on wed 19 apr 06


Glad to hear that you're back to being 'hands on'! It sounds as though
these glazes might be more trouble than they are worth, especially as
you'd been having fit problems - do you have the space to maybe store
them away until you have lots more time & energy to do glaze tests
with them after you have fiddled with them?

I think you deserve a fresh start - if you can afford to begin with
the new glazes and a fresh start with the book, why not treat yourself
to that and forget about the old glazes for another year or so? Maybe
pour a pint or so of water onto the top of the old dried up glazes &
see if they re-hydrate by themselves.

I think there is only so much time & energy to spare & you would be
better off starting afresh, getting glazes mistakes/errors/different
results than you'd hoped can be deflating & draining & unless you
really can't afford to, I'd start again.

Best of luck! I hope you post some pics of your new glazes somewhere
we can see!

Kate/karen

Jennifer Boyer on wed 19 apr 06


YIKES, don't throw out your glazes!

Part of being a potter is getting a feel for how thick the stuff
should be in the bucket.

I'd start with a graduated cylinder and a scale. Mix up your glazes
with water and sieve them. Take a graduated cylinder(to measure glaze
volume) and weigh it on your scale. Rezero the scale and weigh 100
ml of glaze in the cylinder. Keep detailed records. In my experience
since I learned this method from John Britt's book, 100 ml of glaze
that likes a thin application will weigh about 145 grams. A thicker
glaze will weigh about 165 grams. You may want to start with a sample
of your glaze and try to get about 165 grams, then thin it out so 100
ml weighs 155 grams then thin it out again so it weighs 145 grams.
So you'll have 3 tests to try in your firing and the one you like
will be repeatable since you'll know what 100 ml should weigh. If you
don't want to fill a kiln with tests, then buy some new glaze to use
while you try this kind of testing. This weighing thing is a great
thing to know especially if you are in glaze test mode. I think many
people test a glaze using one thickness, then abandon the glaze when
they don't like the first test. But if they fiddled with the
thickness there might be a great glaze surface waiting to be
discovered! Good luck and have fun getting your hands clay-ey again.
Jennifer
On Apr 19, 2006, at 5:37 AM, katetiler wrote:

> Glad to hear that you're back to being 'hands on'! It sounds as though
> these glazes might be more trouble than they are worth, especially as
> you'd been having fit problems - do you have the space to maybe store
> them away until you have lots more time & energy to do glaze tests
> with them after you have fiddled with them?
>

*****************************
Jennifer Boyer
Thistle Hill Pottery
Montpelier, VT
http://thistlehillpottery.com
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