The Varieties of Glass Tile: Production Methods

Glass tiles can be categorized by manufacturing method. In this article we outline five main methods:

smalti, fused, sintered, cast and slumped.

Most tiles fall into a single category, although some tiles, for instance slumped tiles, involve a second method .

Smalti tile

Smalti tiles are typically colorful, textured, small format tiles - good building blocks for artistic mosaics.

“Smalti” is an Italian word, and refers to a glass paste or glaze made up of silica melted with sodium or potassium carbonate. Metals are added as stabilizing agents, as well as metal oxides ( for color). The paste is fired at high temperatures, then rolled out into a pancake- like slab that can be up to 6 inches thick. Once cooled, the slab is traditionally hand-cut into small rectangular pieces of tile.

For more on Smalti tiles, click here.

Fused tile

In the fused method, flat glass ( usually float glass, such as glass used on car windshields) is cut into tiles shapes and then fired in a furnace. As glass is clear, it will show the tile underpay unless treated with color, so this method usually involves the addition of color - by adding it on top or under the glass. Fused glass tiles are often translucent tiles, with a layer of opaque color visible through the tile.

Fused tiles are often treated with an etching or other coating, for aethetic reasons, or to increase resistance to abrasion. Fused tiles can come in virtually any size - from mosaics to large format.

Sintered tile

Sintered glass tile is made by pressing glass powder into dies and then heated until the particles
fuse. These tiles are often sold in arrays of 1” x 1” squares, but can come in sizes up to 3" x 3".

In this method, color is either added into the powder or added topically after cooling. Unlike smalti tiles, sintered tiles tend to have a uniform look. With their milky, scratch- resistant finish, sintered tiles are known for their versatility.

Cast tile

Cast tile is made by inserting chunks of glass into a mold. The mold is heated until the pieces melt into each other and become a coherent mass. The result is a layered look. Most recycled glass tile products are made using this method.

Slumped tile

Slumped glass is glass that has been curved into a shape during firing. Slumped glass tiles are usually produced by melting plate glass into relief molds. On cooling, the glass assumes a curved or contoured shape.

 

 

 

 


Gold leaf Smalti tiles



Meshmounted sheet
of fused glass tiles



Cast glass tiles



Slumped glass molding