Ron & Dianna Phillips on sun 7 dec 97
Why do we get so many requests for a "good cone 6 clear"? It has become
the next "better mousetrap"! What's wrong with the cone 6 clears we
The only trouble I've *ever* had with any clear glaze is crazing where it's
too thick, and I avoid that by sponging the glaze on, when I don't want it
I think crazing can be kind of attractive, anyway. Now if I could just
learn to appreciate shoveling snow, since once in a while it's inevitable
Mmpottery on mon 8 dec 97
Please tell me more about "Sponging it on". I have never heard of this.
Allison Stelter on mon 8 dec 97
My ^6 clear often bubbles...tiny small rough bubbles. Other times it's
Any advice or suggestions?
Stephen Mills on wed 10 dec 97
are you using cones or a pyrometric controller? if the latter, it needs
checking,sounds like occasional overfire or maybe under.
message , Allison Stelter writes
>My ^6 clear often bubbles...tiny small rough bubbles. Other times it's
>Any advice or suggestions?
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Tony Hansen on thu 11 dec 97
>Why do we get so many requests for a "good cone 6 clear"? It has become
>the next "better mousetrap"! What's wrong with the cone 6 clears we
Not really. Many of the ones we have are not hard and
durable enough, they are not resistat enough to leaching,
they don't work with chrome tin pink stains or others, they
don't suspend properly, they apply with drips and runs, they
are not transparent enough, they crystallize boron blue,
they are not adjustable for temperature, expansion, etc,
they employ unreliable materials, they are too runny and
smear the edges of color too much, they don't take
opacifiers well, they gel over time, they shrink too much
during drying and crack and crawl, the have too many suspends
bubbles, etc. etc. A good
transparent glaze is very difficult to achieve, there are
so many properties to consider.
> The only trouble I've *ever* had with any clear glaze is
> crazing where it's too thick, and I avoid that by sponging
> the glaze on, when I don't want it to craze.
Crazing is the biggest single problem I did not mention
above. Crazing means the thermal expansion of body and glaze
do not match and no band-aid approach will work, you must
adjust the glaze recipe to reduce its expansion.
> I think crazing can be kind of attractive, anyway.
A clear transparent glaze is typically used for functional
ware. Crazed ware can be 300% weaker (I am not exaggerating).
It is very important that a base functional glaze fits well
and that is not at all an easy thing to achieve. There are
well defined techniques to employ to fit your glaze to
your clay and these are vital for optimal functional ware.
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