Expert: Leisha Hiester - 11/29/2011

Question
QUESTION: need to make 20 inch square tile that about 1 and half inches thick
what percentage of grog should i use if i fire them at 05

ANSWER: Dear Daniel,

Sorry to take so long to reply. I also raise Huskies and my bitch just had 6 gorgeous pups!!

With tiles, the key is to use grog to help prevent warping as the tiles are drying. The grog opens up the clay and aids in even drying. The rule of thumb is 20-30% grog addition.

Keep in mind shrinkage. I highly recommend a shrinkage test first.

Hope this helps. Leisha

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

QUESTION: I'm forced to fire the tiles standing up or on edge because of space and shelf conciderations
Any suggestions about this method? How slow should i fire them ? they are goung only to 06 with a red underglaze, how do  I stop the glaze from dripping out of the carved design on top?

Answer
Daniel,

Are you standing your tiles up on edge by themselves? I have a tile rack I use. If you don't have one, you might want to create some type of spacer in between them with clay or with stilts.

I would fire them as slowly as possible.

I use simple house wax to prevent dripping. I strongly encourage you to do a test first. I picked up an old electric fry pan from a garage sale. I watch for them at places like Goodwill too. I set the temperature at 300 degrees and melt common household wax in it. Past 300 tends to start smoking. I use up old candles this way. I have a few sizes of old brushes designated for the wax. I brush it over the glaze I want to keep in place. I keep a very small amount in one for dipping the bottom of some pots when I suspect the glaze may be a bit runny. This is an excellent technique for dipping too. If you have a pattern you wish to hold back on you can wax it first, then dip the entire pot. Be sure to sponge off any remaining glaze droplets from the wax before firing.

Hope you'll write me back and let me know how your tiles turn out! Leisha