Pottery, for Artists, Craftsmen & Teachers

by George James Cox

—Sixteenth century memorandum.

Tiles may be made of various kinds and sizes, but in every case they show an inclination to buckle in drying and firing. The larger the tile the stronger is this tendency to warp. The clay must not be so rich as that which is used for throwing and should be tempered to counteract the tendency to curl.

A tile box as shown in Fig. 39, or a variant of it, will be required for pressing tiles by hand; for plain tiles ⁵⁄₈” deep, for others 1¹⁄₄” deep, the size being calculated to allow for shrinking. The sides hinge and the thumb screws keep it steady on the bench during work. For rough tiles, two strips nailed to the table will serve, the clay being rolled out between and cut in lengths as required.

For plain tiles the wedged and tempered clay is batted out into a slab a full ³⁄₄” thick. The mould is dusted with French chalk, flint, or very finely

sifted clay dust, to prevent sticking, and into it is pressed a piece cut to fit easily in the tile box, from the slab. This is firmly pressed into the box, considerable pressure being used. The surplus is scraped off and the top trued with an iron straight-edge. The knife can be run round the sides, then with the frame reversed a smart tap on the back will release the tile.

Fig. 39

Let the tiles toughen and then pile in stacks with flat pieces of clay or old tile between each corner and a true biscuit tile at bottom and the top. They can be piled one on the other with sand between or stacked like bricks with alternate holes for the

air to circulate. This retards the drying, but in any case they must be dried slowly. With plain glazed tiles a little coarse dust sprinkled over the surface before the tile is removed from the box, and well pressed in, will give a slight interest to the surface and take away any mechanical look. If required for painting, the clay must be very finely sieved and the surface will need careful finishing by hand when dry. With coarse clay, a fine surface can be imparted with a flexible broad palette knife.

For raised outline tiles a frame 1¹⁄₄” deep is required. This allows a plaster bat ⁵⁄₈” thick to be placed at the bottom. The best way, perhaps, is to oil the frame and cast the bat in it, removing it when set and sandpapering the upper surface flat and true. The design for the tile drawn the exact size on paper is now traced on this surface. It is far better to sketch it directly onto the slab, but this demands some proficiency if the surface is to be preserved. The design is then incised with a firm sharp point, clay squeezes being taken from time to time to show the progress of the work. The plaster should be wetted to insure easy working. At the finish the design should stand out in a fairly strong and deep line—square—not round or angular in section. (Fig. 40.) A chisel-pointed hard pencil will be found best for finishing. This gives a clear-cut line, not too round. The bat,