Rodney Roe on mon 25 oct 10
I'm interested in making vessels with a water proof liner glaze and exterio=
cold finishes. Anyone have experience or ideas about how to do this?
David Finkelnburg on tue 26 oct 10
You do not mention what temperature you will fire to. At mid to high
fire (cone 3 to 10), I would suggest you fire the vessel to maturity, that
is, until the clay is sufficiently vitrified that it is water tight. That
way even if your liner glaze is not perfectly water tight you'll never have
a vessel leak. Use a liner glaze if you need it for function--cleanability=
Full vitrification can be a challenge at low fire (~cone 04), depending
on the clay body you select. If the body is one which is on the tipping
edge of bloating/slumping at vitrification you have no choice but to rely o=
the liner glaze, in which case glaze fit will be critical.
You mention single firing. A slip glaze may be good for you because
you'll be green glazing. Preferably you'll glaze at leather hard. Bone dr=
clay may absorb too much glaze moisture and then crack.
If you need help with how to fire to full vitrification, but not beyond,
see the archives under absorption testing. All you really need to know is
that fully vitrified clay won't absorb much water. Less than 3% water by
weight of the dry ware after firing for stoneware, less than 1/2% typically
for porcelain. Low fire clays are sometimes in the range of 15-20%
absorption after firing but still produce functional ware (though not
On Mon, 25 Oct 2010 Rodney Roe wrote: I'm interested
in making vessels with a water proof liner glaze and exterior cold
finishes. Anyone have experience or ideas about how to do this?