How the Technique Works

While iridized surfaces won’t stick to each other, they will stick to non-iridized glass. By strategically sandblasting away some of the iridization on two sheets of glass, you can get enough of the glass to fuse so that the places where irids overlap will not be a problem. If that sounds a bit confusing, don’t worry. The next few illustrations will explain.

Step 1: Mask the Iridized Surfaces

Irid-on-Irid technique

The above illustrates two pieces of iridized glass. The top left piece is blue glass with iridization and the bottom left piece is clear glass with iridization. Masking tape stripes are applied to the iridized surface of each piece, as shown on the right.

Step 2: Sandblast the Glass

The iridized film is very thin and can be quickly and easily removed in a sandblaster. Masking tape will protect the iridized surface. When tape is used this way it is called a “resist” because it resists the sandblasting.

We can see this process in the following sequence of pictures:

Irid-on-Irid technique

Here, again, we have the blue glass with iridization on the top and the clear glass with iridization on the bottom.

The first set (on the left) are as we left them in the last image – masked with tape.

In the images in the middle, the exposed iridized surface has been blasted away, leaving only the bare glass (and the iridization that is currently hidden beneath the tape).

In the images on the right, the tape has been removed revealing the iridization that was protected by the tape resist.

Step 3: Stack the Layers

The next step is to properly orient and stack the two layers.

Irid-on-Irid technique

First, flip the clear layer over so that the iridized stripes face down. Now, rotate the clear piece a quarter turn (90°) so that the stripes run the opposite way (horizontally) of those on the blue glass (vertically). Place the clear piece on top of the blue piece and you’ll see something like what’s shown in the tile on the right (above) and enlarged (below).

Irid-on-Irid technique

With the two layers stacked, and with irid surfaces facing each other, there are four possible combinations:

  1. Where the iridized (unblasted) surface of the blue glass touches the blasted surface of the clear glass.
  2. Where the iridized (unblasted) surface of the clear glass touches the blasted surface of the blue glass.
  3. Where the blasted surfaces of both glasses touch each other.
  4. Where the iridized (unblasted) surfaces of both glasses touch each other.

Only the spaces where irid is touching irid will not fuse together. Every place else fuses just fine! In most cases, that is more than sufficient to create a fused, stable project.

Here’s a photo showing the exercise above in actual glass:

Irid-on-Irid technique