iandol on sat 26 aug 00
glaze lining, just pure plain salt fired plates, bowls, and mugs.>
Miccaaa,
The quick answer is, it all depends.
Salt firing was common a couple of centuries ago and gave a smooth =
surface on fine white firing clays. Ideal for domestic ware and overcame =
problems due to lead contamination.=20
There are two things which should be thought about. The first is the =
temperature at which the clay matures at. This must be achieved and give =
a fully vitreous body with a minimum of porosity, less than 2%.
The second develops from the knowledge that high sodium glazes have high =
coefficients of thermal expansion and are notorious for crazing, though =
because of the nature of the surface and the corrosive effect of salt on =
the body this defect is not obvious unless you search for it. There =
seems to be a convenient collective amnesia on this point in the =
literature. Ron may care to make a comment on that.
The conclusion which must be drawn is that if the body is not mature or =
salting is done early, or there is a lot of residual salt in the kiln it =
will be absorbed unchanged into the underfired clay. Unreacted Sodium =
chloride which remains in the clay will leach out through the crazed =
surface and contaminate the flavour of the food or beverage. I have =
talked to retailers who would not entertain saltgalzed domestic ware =
because of that possibility.
Having said that, I would like to add one of Jane Hamlyns mugs to the =
collection in the pantry. Her work is the acme of domestic salt glaze =
design. Mugs, jugs, casseroles and containers, superb useable domestic =
pottery
Ivor Lewis. Who glazes domestic ware with a high sodium glaze and =
thrives.
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