Dave Carhart on tue 22 oct 02
I mixed a white slip for use on leather hard cone 10 stoneware.
22.5% clinchfield feldspar
22.5% flint
22.5% tennessee ball clay
22.5% georgia kaolin
10% ultrox
Almost without fail the slip falls off when the clay dries. On one bowl
the slip was thick, the bowl was thin and the clay body itself cracked.
It seems my slip needs to shrink more during drying. I took a look in the
archives -- someone mentioned adding Bentonite. How much and are there any
other suggestions to increase shrinkage?
I buy my stoneware pre-mixed so can't reformulate the clay body. I got
most of my ingredients from a guy who originally bought them in the early
70s so maybe I have some non-standard stuff.
Thanks
Ron Roy on sun 27 oct 02
My guess would be - it's not deflocculated - too much water = to much shrinkage.
RR
>I mixed a white slip for use on leather hard cone 10 stoneware.
>
>22.5% clinchfield feldspar
>22.5% flint
>22.5% tennessee ball clay
>22.5% georgia kaolin
>10% ultrox
>
>Almost without fail the slip falls off when the clay dries. On one bowl
>the slip was thick, the bowl was thin and the clay body itself cracked.
>
>It seems my slip needs to shrink more during drying. I took a look in the
>archives -- someone mentioned adding Bentonite. How much and are there any
>other suggestions to increase shrinkage?
>
>I buy my stoneware pre-mixed so can't reformulate the clay body. I got
>most of my ingredients from a guy who originally bought them in the early
>70s so maybe I have some non-standard stuff.
>
>Thanks
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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