Making slip

[BeckyH]

I have been slip casting for about a year now, using slip created by a local company. It is a white ball clay with talc, to which defloculant is added as necessary. I was wondering about using the recipes for flameproof clay bodies and making a slip, which I could then cast. Any hints or techniques would be very helpful.

Also, when recovering dried trim and scraps of cast pieces, I can figure out how much water to add to get the right consistency, but is there any way to test to see if the defloculant is correct?

Thanks!