Lana Wilson created Magic Water and a Paper Clay to hold leather hard slabs together and to mend cracks in leatherhard ( and bisque) pieces.MAGIC WATER
1 gallon water
3 tablespoons sodium silicate(sold at clay suppliers)
1 1/2 teaspoons soda ash
Mix by volume:
1/4 torn up toilet paper ( the cheapest , rough works best)
3/4 bone dry hunks of clay (I smash them in a baggie)
Fill with Magic Water one inch above clay. Let stand overnight. In the
morning,pour off some of the water, mix with a blender. Use as a slip or putty.
When mixed to the consistency of buttermilk, paper clay can be used as a joining slip . A putty mixture is good for patching.
I used Paper Clay + ground up cone (the cone should match the cone you are firing to) to mend a glazed piece. Ever had a small crack in the bottom that does not go through to the inside. This worked, but you must glaze over in a swirl....as if you are adding decoration .....to "hide" the patch.
This is a previous post but is worth repeating. I am using paper clay and ground up cone pieces to mend small cracks on edges...simply reglaze and retire.