Terra Cotta Bodies

L210 - Brown earthenware			L215 - Red talc earthenware
TerraStone - Red school clay

Terra cotta is quite compelling partly because of its long tradition. The production of white-glazed ware on red low fire bodies (generally called Majolica) is an unmistakable trend of the past 10 years. The use of transparent glazes over color slips on these bodies is also developing more than ever.

Our terra cotta bodies employ our native materials to offer formulations with unusual consistency compared with typical terra cotta bodies. Use the L210 if you require a brown body or need to fire to cone 1 or more. Use L215 if you are using commercial glazes.

Firing

Terra cotta bodies develop much greater fired strength than buff or white bodies because they contain many natural impurities that act as fluxes. This is especially true if you can fire to cone 03-02. You will find the brightest and most pleasant red coloration is usually around cone 02 also. While white or buff burning low-fire body surfaces are generally quite boring, the red of terra cotta is one of the most vibrant and exciting surfaces in ceramics. We recommend that you experiment with the entire cone 06-2 temperature range to see all the color possibilities these bodies can provide.

Most terra cotta bodies have a color evolution that is not linear. It is common to see a rapid change from light to dark red or brown around cone 1. Ware fired in this range without good kiln control will be subject to wide variations in color with only slight changes in firing temperature. This violate one of the primary advantages of low fired ware, toleration of firing variations.

Transparent glazes will significantly darken the color of the terra cotta bodies above cone 03. Thus do not be surprised if you get a brown color through the clear glaze when you expected the toasty orange the body displays without the glaze.

Glazing

If you want to make white-glazed highly colored ware you might be tempted to use a white burning body with a clear glaze. However we recommend that you reconsider this. White bodies often yellow when glazed transparent and it is usually necessary to opacify the glaze anyway. Low-fire zircon and tin white glazes have tremendous covering power and if you dedicate your resources to finding a way to get a good even thick coverage of glaze on a red body you will enjoy the benefits of much stronger ware with a better developed glaze interface and yet still have very white ware.

Many traditional terra cotta artists make beautiful terra cotta ware by trailing on multi-colored slips and then putting a clear glaze overtop. Others do incised decoration and fill it will colored slips which they then rub off to restore the smooth surface. The inlaid colored lines provide a good background for the transparent overglaze. If you do terra cotta slip decoration be sure to adjust the shrinkage of the slip so that it does not flake or crack off during drying.

Plainsman Clays Ltd. 702 Wood Street, Medicine Hat, Alberta T1A 1E9 Canada

Phone: 403-527-8535 FAX: 403-527-7508