Sue Warrington on sun 11 may 97
I have a large drum of maiolica glaze that is a mixture of several recipes
however some of the wares are shelling on the rims! As frits are very
expensive I don't want to throw it out. My research suggests that I should
add alkalis possibly Ferro fritt 4110. Has anyone got any suggestions that
might be able to help.
Thanks Sue Warrington
Ron Roy on mon 12 may 97
>----------------------------Original message----------------------------
>I have a large drum of maiolica glaze that is a mixture of several recipes
>however some of the wares are shelling on the rims! As frits are very
>expensive I don't want to throw it out. My research suggests that I should
>add alkalis possibly Ferro frit 4110. Has anyone got any suggestions that
>might be able to help.
>Thanks Sue Warrington
Hi Sue,
It would be better if I knew what type of clay you were using (white/dark)
and what temperature you are firing at.
I did a quick calculation - made a glaze with a low expansion that I knew
would cause problems. Then tried an addition of 20% Frit 3110 (it's the
same as your #4110 I think) to get my hypothetical glaze up to a "normal"
expansion rate. Then I tried an addition of 12% Whiting instead and got the
same results - raised the expansion to a "normal level. A much cheaper
solution without all the melting and running the 3110 would impart.
Before you take the above as a serious suggestion I think I should know
more about your firing cycle and clay conditions. It would also help if we
knew what a known volume (a cup or better still a liter) of the dried glaze
weighs. Then we can talk % additions.
Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849
ronroy@astral.magic.ca
Tony Hansen on mon 12 may 97
Sue Warrington wrote:
>
> I have a large drum of maiolica glaze that is a mixture of several recipes
> however some of the wares are shelling on the rims! As frits are very
> expensive I don't want to throw it out.
By shelling you mean shivering I think. Add nepheline syenite or soda
spar to get as much sodium into it as possible. You might have to fire
a little higher if the addition lessens melting.
--
Tony Hansen, IMC thansen@mlc.awinc.com
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