Earthenware Pottery Manufacturing

The materials for pottery are very common, being clay, feldspar, and flint in varied proportions according to the article to be produced.

After the clay has been removed from the clay bank it is allowed to age for some time. It is said that Chinese potters use the clay which their grandfathers have prepared, and that they in turn prepare clay for their grandchildren. The modern process, however, continues for days, weeks, or months only.

The clay is first molded into the desired shape, either by hand or by machine, and then left to dry for some time.

When the articles are dry they are put into furnaces, called kilns, to be "fired". The better ware is packed in "saggers" or containers, made of fire clay, to protect them from stains, warping, and cracking. The common ware is often piled up in the oven of the kiln without covering.

The kiln is really a huge brick chimney with a floor. When the kiln has been filled with the ware it is bricked up and fires lighted underneath. These are low at first, but gradually become hotter until the degree of heat required for the kind of article being made is reached. Then the fires are checked and the kiln gradually cooled; usually about two days are allowed for this cooling. Then the kiln is opened and the ware removed. It is now in what is called the "biscuit" stage, rough, and without glaze.

After careful inspection the ware is smoothed and any lettering, stamping, decorations, or trade-marks are applied.

The articles are next dipped into a glaze and allowed to dry, and then once more packed in "saggers" and fired. While the temperature is not so great this time as at the first firing, it is great enough to fuse the glaze with the body of the ware, so that the ware and glaze are one, not simply pottery with a coating of glaze.

The glaze on yellow ware and some other forms of crockery is fused on in the first firing.