Testing Notes
Clay Tests
I have minimal knowledge about formulating clay bodies and no experience with creating new/variant clay bodies. So, I wanted to start with a couple base recipes that I really liked to work with. These base recipes were sandy white stoneware and levin porcelain. I sourced them from The Claybucket website. I am not claiming these clay tests to be mine, nor are they novel—I am leaning on my predecessor’s knowledge and work in order to further my own exploration. These are merely variants oriented towards my own preferences in surface and color.
Sandy White Base Recipe
40 EPK
28 Goldart
16 Custer
12 Silica
5 Sand
Sandy White V1
40 Helmer
28 Goldart
16 Minspar
12 Silica
4 Sand
Sandy White V2
30 Helmar
10 Tile 6
28 Lizella
12 Minspar
4 Custer
12 Silica
4 Sand
Sandy White V3
20 Helmar
20 Tiles 6
14 Goldart
14 Redart
8 Minspar
8 Custer
12 Silica
4 Sand
Sandy White V4
20 Helmar
20 EPK
14 Goldart
14 Newman Red
16 Minspar
12 Silica
4 Sand
Sandy White V5
40 Helmar
28 Lizella
16 Minspar
12 Silica
8 Sand
All of these clay bodies threw nicely at a 1.5 lbs scale. Bowl integrity was kept when push past the base. Cup walls were able to be pulled quite thin. Trimming and carving yielded nice cratered surfaces along with sand lines, which could be easily burnished down to taste. Cone 06 shrink rate shows similar across the board at 6.25%.
Levin Porcelain Base
55 Tile 6
30 Custer
20 Silica
2 Red Art
2 Bent
Levin Porcelain V1
55 Helmer
30 Minspar
20 Silica
2 Redart
2 Bent
Levin Porcelain V2
30 Helmer
25 Tile 6
20 Minspar
10 Custer
20 Silica
4 Lizella
2
Levin Porcelain V3
26 Helmer
27 Tile 6
15 Minspar
15 Custer
20 Silica
2 Newman Red
2 Bent
Levin Porcelain V4
30 Helmer
25 EPK
30 Minspar
20 Silica
6 Lizella
4 Med Grog
Levin Porcelain V5
40 Helmer
15 Tile 6
20 Minspar
10 Custer
20 Silica
4 Newman Red
4 Sand
All of these clay bodies throw smoothly. There was a more distinct difference between pure helmer and mixed kaolins for throwing strength. Will have to keep note of surface to see if 100% helmer is worth the trouble. May want to play with some xx saggar clay because digital fire claims some flashing potential. Trimming and alterations were easy and no structural integrity was lost with rewetting and ribbing. Keep in mind that all of these are on a 1.5 lbs throwing scale. Cone 06 shrink rate shows similar across the board at 6.25%.
Slip Tests
Playing around with some slips to discolor and mask porcelain surfaces. Hoping to combine blue and white with other surfaces. Starting with porcelain and decorating with high iron clays. Will soon shift to high iron bodies with porcelain slips. These tests were all at 100% clay of Red Art, Newman Red, C-Red Clay, and Lizella. They were all massed to 75 grams and mixed into 225 grams water for a 1 to 3 ratio. They all brushed on nicely except for Lizella. Lizella is quite rough and leaves a pebbled surface—might need to strain or ball mill to reduce particle size for better spread. These are preliminary surface tests, may want to explore terra sigs in the future.
