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Iridescent Glass

iridescent coated colored glass squares

Overview

Reactive Potential

The iridescent coating is Non-reactive. Neutral. Refer to the sheet glass style for glass reactive potential.

Forms of Glass

Bullseye makes over 125 styles of iridescent (iridized/irid) glass including these categories:

  • Rainbow Irid on Transparents
  • Rainbow Irid on Textures
  • Rainbow Irid on Clear with Clear Collage
  • Gold Irid on Clear, Black, Medium Amber, Light Bronze
  • Silver Irid on Clear, Black, Light Silver Gray
  • Frit – Rainbow Iridescent Clear
  • Special Production
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Detailed Information

About Iridescent Glass
Cold Characteristics

A thin, metallic coating on sheet glass. Irid is a tin-based coating, applied in the manufacturing process. Available in Silver, Gold, and Rainbow.

Colors of iridescent coatings are a function of thickness. The thinnest coating is visible as silver, then as thickness increases, gold, magenta, blue and finally green-gold. This is known as structural color, where colors are caused by interference effects rather than by pigments. Other examples of structural color include iridescent beetles, soap bubbles, and peacock feathers.

Iridescent coatings are visible as metallic when viewed in reflected light. When viewed in transmitted light, the metallic is transparent and the glass color becomes more visible.

Irid is food safe and considered permanent at full fuse temperatures.

Iridescent Frit is made from crushed, iridized sheet glass.

Working Notes

When firing with the iridescent side against a kiln shelf, we recommend using Bullseye Shelf Primer as ThinFire may cause pitting in some coatings.

Iridescent coatings are versatile and have a higher surface tension than the glass. This creates different effects whether it is fired face up, against a kiln shelf, or sandwiched between layers. This surface tension can also create more linear or pointed bubbles when sandwiching an iridescent coating between layers. Samples are (4 x 4″) 6mm and fired to a full fuse.

Left: Rainbow Irid fired face up
Right: Rainbow Irid fired face down
Top left: Clear capped Rainbow Irid
Bottom right: Rainbow Irid up base to Clear Rainbow Irid down cap
Left: Gold Irid fired face up
Right: Gold Irid fired face down
Top left: Clear capped Gold Irid
Bottom right: Gold Irid up base to Gold Irid down cap
Left: Rainbow Irid fired face up
Right: Rainbow Irid fired face down
Top left: Clear capped Rainbow Irid
Bottom right: Rainbow Irid up base to Clear Rainbow Irid down cap

Iridescent coatings have a higher surface tension than the glass, which can be evident in some projects. For example, textured iridescent glass styles may retain some of their original texture, even after a full fuse firing. This is especially noticeable where the iridescent coating has wrapped around the raised accessory glass elements (frit, stringer, confetti).

Remaining texture after Full Fuse firing with Black Prismatic Rainbow Iridescent as cap sheet.
Remaining texture after Full Fuse firing with Clear Chopstix Rainbow Iridescent as cap.

Iridescent coatings often release more cleanly against fiber paper and primed mullite (kiln shelf and dams) than non-iridized sheet glass styles. See Tipsheet 1: Kilncarving

In projects that have significant flow or stretch, the coating is prone to break apart to reveal the underlying glass.

The iridescent coating lends itself to design opportunities including: