Lynne Antone on tue 17 jun 97
Am finally getting into production and my first few firings are giving me
crawling problems. Pots are very clean, so eliminated that source. I only
have the crawling in areas where there are at least two coats of the glaze.
It may be the same glaze where double dipping overlaps or where two colors
overlap. I have thinned my glazes (maybe too much?) thinking the coats were
too thick. I dip once, let it dry very well then dip into the other glaze.
The areas which are crawling I now notice crack and in some cases pull away
from the pot before firing. Remoistening doesn't solve the problem. I'm
wondering if the initial coat is too dry and when the second coat goes on, it
shrinks and pulls the first with it. I've never had this problem before.
My glazes are a blue, green, transparent and white. The white and trans. are
fine alone even doubled, but add the blue or green and it's a mess. The blue
by itself is the worst offender. I fire to cone 6, ox. electric.
Any help is appreciated.
Lynne Antone
Olympia WA USA
pranton@aol.com
Tony Hansen on tue 17 jun 97
> Am finally getting into production and my first few firings are giving me
> crawling problems.
Check the following web page. I think you'll find the answer there.
http://www.ceramicsoftware.com/education/glaze/crawling.htm
Have a nice day.
--
=================================================================
Tony Hansen, IMC thansen@mlc.awinc.com
INSIGHT5/Magic of Fire II demos at www.ceramicsoftware.com
Louis Katz on tue 17 jun 97
Crawling.
I have seen crawling frequently with the addition of Epsom Salts to
prevent settling.
When we mix glazes with distilled water in Nueces County we find that our
glazes don't crawl as often as when we use our hard city water.
Since you are now experienceing this problem with all your glazes I would
suspect the water or the bisque.
Are your glaze recipes all related to each other?
Louis
Louis Katz
Texas A&M University Corpus Campus
lkatz@falcon.tamucc.edu
http://www.tamucc.edu/~lkatz
Lynne Antone on wed 18 jun 97
<Louis Katz
Texas A&M University Corpus Campus>>
Louis, I bought already mixed glazes from a potter leaving the area and
everything was fine at the start. No, the glazes are not related. Most of
them contain some portion of commercially prepared glazes. You did mention
the scary thing I was afraid of, that when you use hard city water you have
problems. The original glazes came from a different area of the county, our
well water here is pretty hard. I have been adding some every time I glaze to
thin the glaze. Is there a way to soften it back? Please say yes! I have
approx. 15 gallons of each of the four offending glazes.
I have not added any Epsom Salts, actually nothing except the well water. You
also mentioned bisque changes. I do a slow firing with both bisque and glaze
firings. Bisque is taken to cone 06.
If my well water is not good to use, how is rain water from the gutters? We
have a new composition roof. Would this water have some chemicals to make it
unacceptable? Here in Washington State I can get rain water year 'round, day
or night. I can also go into town and get water from an artesian spring for
all of my glazes. Is it okay?
Thanks for your help.
Lynne Antone
pranton@aol.com
Kat Berger on fri 20 jun 97
Lynne
I have been finding that if my glazes are to thin or if I let one glaze dry
completely before adding the second glaze I have crawling problems. So try
the other direction. Thicken your glaze again, and put the second glaze on
as soon as you can pick up the piece
Kat
M Richens on sat 21 jun 97
In article <970616172713_-762587547@emout20.mail.aol.com>, Lynne Antone
writes
>----------------------------Original message----------------------------
>Am finally getting into production and my first few firings are giving me
>crawling problems. Pots are very clean, so eliminated that source. I only
>have the crawling in areas where there are at least two coats of the glaze.
Hi Lynne,
Only two comments from me.
How porous is the body?
It may help to water dip first, drain and then do the glaze dipping in
case you are getting too much suction from the ware.
The other suggestion is to add maybe 0.1 - 0.3 % of one of the family of
CMCs (carboxy methyl celluloses) there are about. They can improve crawl
resistance a lot as well as improving cover of dusty ware and giving
good handlability of the dried product.
To prove I can't count maybe you could reduce the clay content slightly
on the glaze. It sometimes helps.
HTH
Max
--
Max Richens max@richens.demon.co.uk +44 (0) 1925756241
Enamel Consultant - Ceramist - Analyst programmer
Software for Batch Formulation and Millroom control.
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