Pottery/Ware Stuck to Kiln Furniture or Stilts
I am new to the field of ceramics and while taking a class, I had several pieces stick to the little plates they were on top of(what are those called?) when they were fired. It seems that I didn't use enough wax on them and had the glaze on too thick. Is there any way I can remove the pieces from their little coasters? any tricks you can recommend? Thank you!
Thank you for your recent question. First, let me tell you that many novice potters have been in your situation, so don't feel too bad. I will give you some tips to prevent this problem in the future, but first lets cover your problem.
From your photos it looks as though your pieces are stuck to the kiln furniture and not the stilts, unless the stilts are underneath and I can't see them. Before beginning, you will need a pair of goggles to protect your eyes. Next you will need a rubber mallet and a piece of egg crate foam. Hold the piece by the rim above the egg crate foam and using a rubber mallet, with a downward force, hit the the kiln furniture on the flat edge. Turn the piece and continue until the kiln furniture releases and drops onto the egg crate foam. It may take several tries to get the piece to release, but should work.
If there is a stilt attached to the piece, turn the piece on its side and hit the stilt with the rubber mallet until it releases.
With luck, there will be minimal damage to your piece. The next step will be to sand down the bottom of your piece. You will need a grinding disk to do this. Glaze is extremely hard and requires grinding to remove it. Wear your goggles to protect your eyes from the glaze dust. Place the bottom of the piece against the stone disk on the grinding machine and hold with firmness so that the piece doesn't slip. Grind until all extra glaze is removed from the bottom of the piece.
In the future, wax will not prevent your piece from sticking to the kiln furniture or stilts. Wax melts and dissipates at a couple of hundred degrees, while your glaze must reach over several hundred degrees to mature. To prevent this from happening in the future, do not glaze your piece completely or all the way down to the bottom edge. Always leave at least 1/4" of unglazed areas at the very bottom edge of the piece. Do not glaze the bottom of the piece at all. If you must glaze the piece on the bottom, use stilts to set the piece on when loading the kiln. Never set a glazed piece on kiln furniture because some glazes do run a bit during firing and will cause the piece to stick.
I hope this helps you. If you have further questions, please feel free to contact me at any time. I am always at your service. Good luck!
Ms. Ti Phillips
Earth Stoke 'N Fire Pottery Studio and Artist Retreat