posted 11 years ago
Prescott H. Paine : ''Fireclay'', is called fire clay for very specific reasons, all clays expand when wet and contract as they dry/cool, the greatest difference between expansion and
contraction is between wet clay and dry clay, Fireclay gets its name from the fact that it shrinks the least, Sand is put into the mix to keep the clay at the micro particle level
from shrinking enough to crack, So it is fire clay because of all of the clays in the world this stuff shrinks lest, It has nothing to do with how much heat it will take !!The only way
clay can be made to crack less is the way Potters have done this since before recorded history, If you are interested,you can look up Grog !
Go to the ''A castable core'' and reread it again, your ratios need fine tuning, you need to make test bricks of your ratios and test them for strength, more is not always better !
For the craft Big AL
Success has a Thousand Fathers , Failure is an Orphan
LOOK AT THE " SIMILAR THREADS " BELOW !