Jerry Rothman "no-Shrink" Clay Body Recipe

[justanassembler]

Hey,

I was wondering if anyone had in their files a copy of Jerry's no-shrink clay body recipe?  I seem to remember it being in an issue of CM a number of years back, but can't for the life of me find it...

 

Thanks in advance,

 

Michael

[Norm Stuart]

Clay, lignite (aka soft coal) and fiberglass sounds like you'd have to use gloves to fashion your ware and a respirator once your clay starts to become dry.  Pyrax (pyrophylite) irreversibly expands when fired.  When mixed with clay the combined effect is a clay which doesn't shrink when fired.

 

Other ceramic ingredients which expand when fired are the lithium feldspar Spodumene, and specialty grogs Kyanite and Mulllite.

 

http://www.grandcentralartcenter.com/press_2003_12_1.php
 

[neilestrick]

I think I'd go with a Spodumene body like a flameware before I used that stuff.

[timbo_heff]

Here's some info that supposedly came from the VC hand book

VC Sculpture Body cone 04 - 6 Also add: Red Iron Ox
2

Narco Fire Clay 10 For more plasticity,
AP Green Fire Clay 10
Hawthorn 7 Macaloid
2
Lizella 3
Fibrous Wollastonite 15 More dry strength,
add nylon fiber
Coarse Grog 25
Medium Grog 5
Fine Grog 20
Calcined Alumina 5

Not very plastic, but can be modeled and shaped fairly well. not ZERO
shrinkage, but very low.

ZERO SHRINKAGE CLAY BODY:

50% coarse grog (4-16 mesh)
10% medium Grog (20-36 mesh)
40% fine grog (40-60 mesh)

Lightly coat these particles with a deflocculated clay slip. This slip
should have
no more than 25% water. (Think of a chocolate coated raisin)

Firmly pack into-around shape. The more firmly packed, the better.
Press clay into whatever voidss may be left in and around the particles.

Dry and fire ---zero shrinkage.

The mixture of coarse, medium, fine grog particles is critical to the body.
This is the standard used by industry in making heavy refractories where
minimum shrinkage is critical.
(From Cushing Handbook).