Thermal Shock Slip Recipe (Help)

[justin1287]

I am looking for a recipe that can handle thermal shock. The finished product when done that I am making is heated with a blow torch. Blow torches can reach temperatures of around 2500 degrees F. The temperature I am looking to heat the product is around 400 degrees, but a lot of users over heat the product and it cracks. The biggest name in the game uses a formula similar to what is used for hip repair. I believe it is heavy on calcined alumina, and they have problems with them breaking. These pieces should be strong enough to be heated several times a day. Does anyone have any ideas of what may work well? My kiln only likes going up to cone 6, and I am looking for a slip recipe. Thanks for any help!