A.Contributing editor Michael Byrne, an
industry consultant in Los Olivos, Calif., responds:
Unless its finish approximates the finish of the uncut edges,
the cut edge of a transparent glass tile can be glaringly
obvious. To minimize chipping, I use a smooth-running wet saw
equipped with a blade made specifically for cutting glass, such
as the MK-215GL (800/421-5830,
mkdiamond.com). So that
there is plenty of clean cooling water, I fit the saw with a
second pump that has its own feed line (this is in addition to
the saw’s built-in pump). I also reduce vibration and
support the kerf edges by clamping a 3/4-inch plywood table to
the saw bed, which provides backing and reduces the chipping
that tends to occur at the tail end of the cut, where the tile
body is at its weakest (see photos). I feed the tile into the
diamond wheel very slowly, easing up even more as I near the
end of the cut.
A plywood table clamped to the tile saw’s bed (left)
and a second water pump with a separate feed line (right) help
reduce chipping when cutting glass tile.
Most glass blades leave a surface finish in the 200- to
400-grit range; subsequent grinding and polishing are required
until the edge finish comes close to the tile’s original
finish and luster. Production installers use wet-bath disc or
vertical belt sanders, but you can also get satisfactory
results with sanding blocks and fine grades of wet sandpaper.
Start with a coarser grit and work your way up to 1,500-grit
paper, using plenty of clean water.
Approximating the edge finish is one part of achieving a
successful cut; another is getting the installation right.
Since most cuts are located on the perimeter of an
installation, they normally border movement joints, which are
made with backer rod and sealant. To make sure the backer rod
isn’t visible through the translucent glass tile, I coat
the adjacent cut edges with thinset mortar. If you do chip the
color coating that’s applied to the backs of some glass
tiles, the best way to repair it is with paint or epoxy
provided by the tile manufacturer. You can sometimes get a good
color match with automobile touch-up paints. But whatever you
do, don’t use nail polish, because it can react with
cementitious materials like thinset mortar and grout and spoil
the edge treatment.