Expert: Sam Kelly - 2/8/2009

Question
QUESTION: We glazed and fired in a kiln, bisque bowls at cone 6.  The glaze is a comerical Mayco brand glaze.  Can we apply clear glaze (same brand) and fire it in the kiln again?

ANSWER: yes you can, BUT the pot needs to be warmed up in the kiln/oven BEFORE you apply the clear glaze. By warmed up I mean to hot to handle with bare hands, but not as hot as a casserole in the oven with a chicken in it ready to take out, so about 100-150DegC.

The reason being is that you want the glaze to start drying on the pot straight away, if you apply it to a cold pot it will just run off.

The best and only really successful way I have found to do this process is to spray the glaze on. An ordinary car painting spray gun is all that you need. spray straight onto the hot pot as soon as you take it out of the kiln/oven. Not a great deal of glaze is needed, as long as you can see that the pot is covered, even if you can see through it is enough, because when you do the refire they will melt together.

Sam

---------- FOLLOW-UP ----------

QUESTION: Can we glaze and fire tiles we purchased at a home store (that were finished for appling to floors) or dinner plates that we can buy at WalMart?
I really appreciate you taking the time to answer my novice questions!

Answer
What you will have to test is the firing temp and glaze compatability. put some glaze in the middle of the plate or tile and fire to your glaze temp. sit the pot on a sprinkling of sand in the kiln, this will help look after the kiln shelf if the pot melts.
While you are at it paint a design or what ever with underglaze on a white plate or tile, apply by brush some clear glaze on a section, fire and compare between that with clear and no clear.

Sam