Alternate Names: Glaze #1, #1 Glaze Clay
This is a high alumina, low iron ball clay (typical ball clays are 25% or lower alumina). As its name suggests, it works well as a suspender and hardener in glazes, especially for white and transparents where the cleanest possible materials are needed. The Old Hickory No. 5 ball clay is a similar material. Use less than 20% (in glazes having no other clay materials) or problems with gelling could occur.
Crude Color: White
Dry M.O.R. (psi 50% clay/50% flint, cast bars): 400
Wet Sieve Residue, +200 mesh (%): 0.20
Water of Plasticity (%): 32
Linear Dry Shrinkage (%): 6.2
Solubles Sulfates (ppm): 183
Filtration (ml): 26
Specific Surface Area (sq meters per gram): 18.0
CEC/MBI (meq/100 ml): 9.5
Firing Shrinkage (%) Cone 04: 4.1 Cone 3: 5.5 Cone 11: 6.8
Absorption (%) 15.9 12.0 5.4
Particle Size (% finer than):
50 microns: 100
I poured 4 teaspoons of two glazes onto a non-absorbent butcher’s board and let them sit for a minute, then inclined the board. The one on the right employs Gleason Ball clay, the left one has Old Hickory #5 ball clay. Neither has any slurry property modifier addition. The one on the right has settled and on incline the watery upper is running off. The other has gelled and the whole thing is running downward slowly. Below I have begun to sponge them off, the one on the right is sticky. The most amazing thing about this: This difference appears despite that there is only 7% ball clay in the recipe.
Ball clays are abundant and very plastic and are used in all types of plastic forming bodies. They are not as white-burning or refractory as kaolins but lower in iron and fluxes than bentonites.
|Materials||No. 5 Ball Clay|
No. 1 Glaze ball clay data sheet