jeff walker on thu 1 mar 01
Ok, I am baffled. I am down to water supply or clay body. Every spring =
for the last 5 years I seem to get craters or small eruptions (IE LARGE =
PIN HOLES) in my glaze all over the pot. The glaze you ask Reitz green. =
I have used this glaze alot, and most of the year it is fine. I buy =
all my supplies in large quantities and dry mix 10000 gram batches to =
wet down later. It does not seem batch related, even though I am going =
to try mixing a different batch again with distilled water instead of =
city water this time. It even effects my copper red glaze, but not in =
the same way. Just not all over the pot, only on the rims ( top and =
under sides).
Any suggestions??? OH Great glaze gods out there, can you help?? Help =
is needed and I don't know where to turn right now. Its not a good time =
of year to have this problem with production in full swing.
HELP!!!!!
JD Walker
in the cold Midwest
jdpotter@iland.net
Dennis Mummert on thu 1 mar 01
Ok, I am baffled. I am down to water supply or clay body. Every spring for
the last 5 years I seem to get craters or small eruptions (IE LARGE PIN
HOLES) in my glaze all over the pot.
This is your clue. I see that you're on city water. Their water quality,
no matter how much control they claim they have, changes seasonally. Spring
is a time of rains and melting snow, which tends to flush solubles and
particulate matter into the gravel beds, and from their into the city wells.
Additionally, some municipalities flush their hydrants once a year (also
sometime in the spring, I would guess). The end result is a variable soup
coming out your kitchen tap. Particulate red iron oxide in particular, and
some sulfur/metal compounds.
I always use water from my reverse osmosis filter for glaze mixing and slip
bucket filler.
Tom Wirt/Betsy Price on fri 2 mar 01
Subject: Re: Glaze Problem: crators in the spring only!!!
> Ok, I am baffled. I am down to water supply or clay body. Every
spring for
> the last 5 years I seem to get craters or small eruptions (IE LARGE
PIN
> HOLES) in my glaze all over the pot.
My Opinion on this one....(and I've asked Betsy if it's OK to
post)....I don't think it's the water....there aren't enough chemicals
in there to make this level of difference.
My take is it's that 3 or 4 weeks off. Your glazing rhythm changes
and (probably) you are applying the glazes more heavily as you start
up again. Note that the glazes had to be right on the edge
before....prone to cratering, but when applied thin enough the healed.
Apply them a little thicker and wham, they bite you. We've noted that
teh glazes that are doing this are high in dolomite or light in
silica. The other glazes are fine.
I think it's that old story when things go wrong in pottery. We are
dealing with systems that have many variables and are working right on
the edge. Then when one variable shifts, the whole thing collapses.
Whether its a minor shift in clay composition, firing schedule,
forming techniques (thicker or thinner walls) glaze ingredients, glaze
technique...whatever....it's enough to throw the system results off.
So, that's my take.
Tom Wirt
Lili Krakowski on fri 2 mar 01
Your water supply may be different! I used to be skeptical about water
being a problem maker. No longer. IF IN DOUBT mix a batch of your glaze
with distilled water (from the autosupply place not from drugstore which
water has to meet medical standards and is far costlier than what is used
for batteries.) Well water varies as does public water becaue sometimes
at some seasons they have to add extra stuff...or so I was told when once
we were getting pure chlorine it seemd in NYC)
Lili Krakowski
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