KYSOCKSOFF on wed 17 dec 97
I am using a C7 porcelain slip from Standard ceramic- #130 (therefore I don't
know the composition) and am having some distortion of finished ware
especially on open forms such as thin wall bowls. The S.G. and viscosity are
tighly controlled - the pieces are allowed to dry in the molds for 24 hrs. in
a draft free area to avoid uneven drying or handling stresses. The pouring and
draining is done to minimize any wall thickness difference. They are bisqued
to 1940 and have thin coatings of glaze evenly applied by air brush afterward.
No problems through bisque but sometimes severe distortion in glaze fire. On
thin wall pieces the temperature rise is 150 F/hr to C7 with no soak and falls
away at 500 F/hr. The kiln is electric/vented and the pieces are located away
from where the venting might cause temp. variation. Any ideas or any past
references I might search for? Clay problem vs. process? Thanks
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