Beverly Crist on thu 24 jul 97
Recently I have been experimenting with cone 04 majolica, with decent
results, however I have been having a problem when I try to use another glaze
inside of a piece which has the majolica on the outside. The problem is glaze
blistering, mostly with the other glaze. If the piece is all majolica then I
don't have much of a problem - just a few outgassing bubbles. The clay is a
red earthenware, Armadillo's Longhorn Red, bisqued to ^o4. The majolica
recipe is a variation of Terry Siebert's:
Pemco frit P-311 69.3
Flint 9.6
EPK 11.5
Zircopax 9.6
(I changed Terry's recipe by bringing it to unity and by substituting pemco
frit for ferro 3124 which she uses. I don't think the changes that I made to
the majolica are the problem.)
I've tried two clears with this glaze. One is Gare GG-1700 which I am
over-firing since it is a cone 06 glaze. It has lead and boron in it. I
overfire it on a white earthenware clay painted with underglazes all the time
and have never had a problem. The other clear is 60% ferro frit 3134 and 40%
OM4 ball clay. It doesn't blister as bad, and again on my other clay I
haven't had a problem.
So my question is, why can't I use these glazes inside my majolica pieces? I
glaze fire slowly, 8 1/2 hours to reach 04 and this last time I tried a 1/2
hour soak. Also, I pre-fire the non-majolica glazes onto the work at cone 018
first to help in glaze application.
Any help would be greatly appreciated.
Beverly Crist
Dallas, Texas (and I thought Florida was hot)
atcrist@aol.com
Tony Hansen on sat 26 jul 97
> So my question is, why can't I use these glazes inside my majolica pieces? I
> glaze fire slowly, 8 1/2 hours to reach 04 and this last time I tried a 1/2
> hour soak. Also, I pre-fire the non-majolica glazes onto the work at cone 018
> first to help in glaze application.
My recent experience with Majolica is that 8 hours is not slow. We fire
12-15 hours. 100 degrees per hour near the beginning tapering off to 50
per hour near the end with a soak. Be careful not to overfire. A kiln
controller
is a must to get yourself going on majolica more quickly.
This firing requirement makes me wonder if Majolica is really more
energy
efficient.
--
T o n y H a n s e n, I M C thansen@digitalfire.com
=========================================================
INSIGHT5/Magic of Fire II demos at http://digitalfire.com
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