A few weeks ago, we presented an excerpt from the new Ceramics Handbook, Wall Pieces. The response to that post was so enthusiastic, that we decided we should come up with a free download on ceramic tile.
For today’s post, I thought I would share an excerpt from How to Design, Make and Install Ceramic Tile Murals and Mosaics. In this excerpt, I am presenting a cool technique that Jerry Goldman came up with to make custom ceramic tile mosaics. He started out making mosaics out of shards of commercially manufactured tile, but this method didn’t provide him with the colors he desired. So he came up with his own method of casting slab tiles with slip stained with metallic oxides and commercial stains. See the technique below.- Jennifer Harnetty, editor.
Years ago, Jerry Goldman was inspired by a friend who made wonderful mosaics out of tile remains from kitchen and bathroom installations and make great works. Jerry decided to try this technique. He liked it, and got his tiles from the usual sources at first. Seeking to augment his palette, he found the dump sites of two manufacturers, one in south New Jersey and one in Massachusetts, and worked with these tiles. But it was not enough. He felt a need for something more, not that the tiles weren’t wonderful – technically hard, vitreous, nice looking; it’s just that he wanted a greater color range, and the cold perfection of the pieces moved him to start making his own.
For years, he blended metallic oxides and commercial slip stains to make many thousands of color tests that he carefully recorded. When he came upon a color he wanted, he mixed a quantity and cast a slab about 5/16-inch thick. When he had a kiln load of slabs, he stacked them one on top of another to conserve kiln space, which resulted in a couple of wonderful effects. First, the center interior of the stack never got quite enough oxygen, so there was reduction and marvelous color variation; and second, some of the tiles cracked, creating even more color variation where oxygen circulated around cracks.
The Poured Ceramic Tile Mosaic Process
Paint the mold with colored slip then immediately pour the required amount of uncolored slip into the mold. There are two reasons to do this: metallic oxides can be costly and require care in preparation, and using a solid-colored tile is unnecessary for this project. Use a level to set the mold. Slip, like water, seeks its own level, so a level mold assures a slab of uniform thickness.
Allow the slab to dry. If the slab is left in the mold too long, it will begin to curl. As a matter of fact, the slab will continue to curl the longer it is left in the mold, and will curl even more during the drying and firing stages.
Remove the slab from the mold as follows: Completely cover the clay with newspaper then place a piece of plywood cut to the size of the mold on top. Firmly grip the mold and plywood together with both hands and flip it over in one quick movement. Place the slabs so that both surfaces will have a chance to dry evenly, such as on a grate, or flip them over from time to time.
If you want a tile with a flat surface, cover the clay with a newspaper laid flat and roll it on both sides. To diminish the possibility of edge cracks, burnish the edges with a knife.
Stack the dried slabs in the kiln and fire them to maturity. For illustrative purposes, he removed the tiles and restacked them on a ware board to show what the stack looked like in the kiln. This illustrates the variation achieved using this method. Tile 1 was on the top, Tile 2 was just under Tile 1, Tile 3 was below and Tile 4 was close to the middle of the stack. To mount the mosaics, use a durable sheet material framed with the material of your choice. This backing is made of 3/8-inch thick treated plywood and a nice hardwood for the frame.
Assemble the mosaic. In this photo most of the mosaic was assembled; this is one of a series of roots and rocks. The root was made of plastic clay and formed completely in that state. He allowed for about 20% shrinkage in the drying and firing.
Finish the mosaic with grout. There are many different colored grouts available in tile shops and home centers. Black grout usually has powerful colorants, but if that gets on the tile, it can darken the tile or make the cleaning of it very difficult. If you want a darker grout, you can paint the grout after it is in place in the mosaic. Tile store and home improvement centers carry abundant stocks of tile adhesives, and have tools as well as helpful, knowledgeable staff.
Tools for Working with Fired Ceramic Tile