Clay Testing Pt. 4 (First Real Success)

So same as the previous round of testing, I have made alterations to the recipes in order to improve their firing properties. Some of the alterations I made are as follows: Decreasing the iron content as iron acts as a flux in a reduction atmosphere, increasing the amount of ball clay to increase firing temp slightly, reducing added feldspar also to increase firing temp, and some include multiple of the listed alterations.

The recipes for each test:

Test 1B - Newman Red Fireclay 50%, Unami Creek PA Clay 30%, C & C Ball Clay 15%, G200 EU Feldspar 5%

Test 1C - Newman Red Fireclay 50%, Unami Creek PA Clay 20%, C & C Ball Clay 25%, G200 EU Feldspar 5%

Test 5B - Newman Red Fireclay 30%, Hawthorn Bond Fireclay 25%, C & C Ball Clay 15%, Foundry Hill Creme 15%, G200 EU Feldspar 10%, Unami Creek PA Clay 5%

Test 5C - Newman Red Fireclay 30%, C & C Ball Clay 25%, Hawthorn Bond Fireclay 15%, Foundry Hill Creme 15%, G200 EU Feldspar 10%, Unami Creek PA Clay 5%

Test 6 - Newman Red Fireclay 35%, Foundry Hill Creme 15%, Unami Creek PA Clay 20%, C & C Ball Clay 25%, G200 EU Feldspar 5%

From left to right: Bare clay test, clay with VT kaolin on right half and dipped in a white satin glaze, clay test with PA clay on right half and dipped in a white satin glaze, clay test dipped in a white satin glaze and double dipped for thickness test.

Honestly looking at the results Id say most of them were pretty successful. Out of the five recipes I am going to continue onto the next steps with two or three of the recipes and start making actual pottery with them to figure out warping, glaze/ slip interaction on a larger scale, and general workability in real scenarios. for the other recipes I will be continuing to make changes to see if I can also gain more desirable effects. Those would be to reduce the amount of bloating that still seemed to show through.

For the next experiments i’ve been thinking of adding kaolin. I know, depending on the amount I add, it will lighten the color slightly but I do think that could be another avenue to increase firing temperature since kaolin is highly refractory. I might play with adding maybe 10% - 15% VT Kaolin to the recipe alongside Grolleg Kaolin as that is a standard ingredient we have here in the pottery. Not too sure where else Ill be focusing on but if you have any recommendations on increasing firing temperatures or general thoughts let me know!