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slip for bisque

updated tue 15 jun 10


Lili Krakowski on mon 14 jun 10

Question the other day about slip for bisque.

The "never fail" slip used on leatherhard or maybe greenware did not =3D
work on bisque. =3D20

Clay/slips/glazes that think together, shrink together....All along the =3D
line it matters to co-ordinate, harmonize shrinkage. =3D20

However. For one Rhodes writes that to increase shrinkage in a slip one =
adds more ball clay in relation to kaolin; and to decrease shrinkage on =3D
adds kaolin at the "expense" of ball clay.

For c.1-6 Rhodes gives:
Kaolin 25
ball clay 25
neph sy 15
talc 5
flint 20
zircopax 5
borax 5
for use on DAMP Clay.

For use on bisque clay he gives:

Kaolin 15
Ball Clay 15
Calcined Kaolin 20
Neph Sy 15
Talc 5
Flint 20
Zircopax 5
Borax 5

The calcining of the kaolin in the "for bisque" recipe lowers the =3D
shrinkage of the slip. Rhodes uses borax to give the engobes a harder =3D
surface. I never use talc in engobes as the magnesium can affect color.

From CM a Pyrophyllite slip worth trying on bisque:
Ferro Frit 3110 12
Bentonite 18
Flint 12
Pyrophyllite 58

For dark slips I always use some RedArt clay...

The Rhodes book is "Clay and Glazes for the Potter" and the original =3D
Greenberg edition has no ISBN!
The pyrophyllite recipe, besides being in some CM issue, appears in my =3D
article, "Showing Your Slip" PMI Vol I, Number 1, Nov.1998

Lili Krakowski
Be of good courage