Iridized glass

[Sherry R]

I purchased a sheet of iridized glass and have used it three times. The first two projects I made, I fired face up and when they came out of the kiln, the glass was just plain blue. I then fired a project face down and it was fine but it was not shiny like firing face up. I asked a shop about it and they said they have never had that happen. This was not the shop I purchased the glass from. I bought it on-line. How should you use iridized glass?

[Morganica]

Many, many questions. First, can you post a picture to show what you're talking about?
Second, what glass did you use? What color and iridization (for example, Bullseye sells rainbow irid, gold irid and silver irid)?
Third, how did you stack it with other glass in the project? (i.e., was the irid side up, so that it was the top-most thing in your stack, or was it facing the bottom layer of glass, so that the irid was on the inside?)
Fourth, what was your firing schedule?
Fifth, how many times did you fire the piece?

Generally, anything you fire face-down on the kilnshelf won't be shiny--the glass takes on the texture of whatever it touches. The only way to get it completely shiny-glassy-looking is to fire it in air, i.e. face-up and don't let anything touch the glass while it's soft. Or cold-work it, i.e., polish it after it's done.

Also, different types of irid can be more or less obvious once fired--silver irid is much less apparent than rainbow, for example. And it can be harder to see if the glass is fired so that the irid coating is on the inside of the glass stack.

[Sherry R]

Morganica; I used Spectum 96. I fired with a layer of clear on the bottom and irid on top. No clear cap. My firing schedule was:
400-1100-10
200-1240-30
9999-1480-10
9999-960-60
150-750-off

I fired the piece only once.

[Judd]

The clear AND the iridized are 96? I thought 96 had made their iridized resistant to kiln forming?

Whatever the case, the iridized has burned off. You can buy 96 iridized that will survive the kiln. Sucks for you.

*Survived - survive - same word.

[Al Bray]

Sherry,

Though I could be wrong, from the picture on the left this glass looks to be from Spectrums Stained glass line vs their 96 fusing line.

I/339-6S - Dark Blue/White, wispy, Iridescent.

In my experience, taking any of the Spectrum Stained Glass line of iridescents up to fusing temps and firing it face up, the irid coating almost always burns off. Firing them face down against the shelf, and the irid coating survives. This seems to be in line with what you are experinecing with this specific sheet of glass.

The irid coating on the System 96 line is specifically formulated so that the coating will not burn off at the higher fusing temps whether fired face up or face down, However I am unaware of the Dark Blue/White, whispy iridecent being offered as a System 96 formulated glass.

I would double check the stock number of this glass and hopefully it wasn't sold to you as a System 96 glass.

- Al

[Laurie Spray]

I am sure that is nonfusable art glass. That being said ....try fusing a double piece of it irid down. I say double piece as you cannot be sure of the coe so you should use it with itself. The irid will probably remain on the down side although it will be matt. When slumping the piece do not fire too hot as then the irid will then be face up and will burn off around 1300.
Who ever sold it to you cheated you for sure!