Firing earthenware to cone 1 or 2

[Tobytyler]

On a recent Clayflix tutorial by Lisa Naples she mentioned she fires her earthenware to cone 1 or 2, which reduces the water absorption rate by a huge amount and renders the clay almost vitreous.  Does anyone have experience with this and, if so, what clay do you use?

[Magnolia Mud Research]

I used cone 05 Longhorn White and Longhorn Red, cone 05 clay bodies (Armadillo clay) fired at cone 3 oxidation .  Fully matured, no absorption, no slumping .   Doesn’t begin to “melt “ till about cone 10+.

LT

[neilestrick]

It depends entirely on the specific clay body you are using. Most Terra Cotta bodies can be pushed up to cone 1 or higher, but many white earthenware bodies will slump by cone 1 and be a puddle by cone 5.

[tinbucket]

I have experience with it, mostly bodies I mixed myself. The higher you go, the lower the absorption, the more brittle the clay becomes, and the closer to over firing you get. Cone 1 or 2 should be ok for most bodies, the only reason I would advise against it is if you dislike the brownish color that can come from firing higher. It's worth a shot and you really won't know if you like it until you try it. Another option which you may be aware of is to apply terra sig to the exposed clay of your pot (usually just the foot ring or bottom). This will drastically reduce the absorption rate of the exposed clay and keep the rich orange color of the clay. My .02 - I think 04 is the ideal temp for terra cotta, a well formulated body will be plenty dense at that temperature and if absorption is really a concern using stoneware or porcelain may be a better option. I think terra cotta is perfectly suitable for functional wares as long as the user is aware of the possibility of chipping, etc.