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Can dichro or irid glass be used for a screen melt? Also, where can I buy welded stainless mesh so I can make my own screens?

Of course they can be used, but don't perform very well at the temps needed for the melt. They don't show up very well either.

I just did my first screen melt. not thinking, I should have grabbed the stainless steel screen out of the kiln before cooling because when you open the kiln there are shards of glass all over that popped off during cooling, they are not stuck but it is a mess and they get into the elements, then the next time you heat the kiln they will stick. I got my screens at Grainger.com but later read on the Forum that Warmglass sells screen but it isn't on the website.

Thanks for the warning. I have tried one screen melt, and it did make a mess in the kiln, but I didn't think about shards of glass getting into the elements. I did find a website for a company called TWP. They sell welded stainless mesh by the square foot. I ordered some and will try to make my own screen.

The problem with metallic coatings (which is what irid and dichro actually are) in any kind of melt/casting is that they're actually separate from the glass and tend to lift off in a sheet. If heated long enough, that sheet will float to the top, where it usually looks more like scum than iridescence.

You can control it with lower, shorter firings, but high-temperature or prolonged firings always seem to have trouble (for me, at least).

Also, irid trapped inside of moving, flowing glass rapidly becomes non-compatable.

Dairy Queen wrote:Also, irid trapped inside of moving, flowing glass rapidly becomes non-compatable.

Why would this be? I'm not even sure what is meant by irid becoming incompatible. Can you please explain what this means?

The iridescent coating sticks to hot glass, but it doesn't stick to another iridescent coating. This has nothing to do with compatibility, as we usually think of it, between glasses. Although thinking about it, 2 irid surfaces are not really compatible...

The irid coating on iridescent glass, like most glass paints we use, and all foils, and various other materials we fuse into and onto glass, is not, and never was, compatible. It doesn't break the glass for the same reason the other materials I listed don't break the glass. Volume. A thin layer of almost anything won't break glass because there just isn't enough mass there to stress the glass significantly. So, the irid does not become incompatible, it always was incompatible. Irid coatings just aren't enough to stress glass to the breaking point. As for this wild surmise:

"Also, irid trapped inside of moving, flowing glass rapidly becomes non-compatable."

Rapidly! Where did that come from? How would you know?

I have been experimenting with the stretch and flow of glass. Irid surfaces can be trapped inside of glass, but if the glass stretches or flows, the irid resists, as it cannot stretch. The stress shows up in the annealing range with major and minor cracking.

By rapidly, I meant the slightest stretch will instantly cause stress and cracking. It doesn't have to be extreme stretching.

Irid doesn't stretch. It breaks. It is an extremely thin coating, and significant movement of the substrate will cause the irid coating to break. This is a well known fact, and I have known it for over 25 years. It does not cause anymore incompatibility than was already there. I have been trapping irid inside glass for most of my career. And, I'm using two layers of irid.

The glass stretching does not cause ANY stress, as the irid was already incompatible . . .

Maybe you are confusing the irid coating breaking with "stress and cracking" . . .

Maybe I haven't learned your method of trapping irid.

Dairy Queen wrote:I have been experimenting with the stretch and flow of glass. Irid surfaces can be trapped inside of glass, but if the glass stretches or flows, the irid resists, as it cannot stretch. The stress shows up in the annealing range with major and minor cracking.

By rapidly, I meant the slightest stretch will instantly cause stress and cracking. It doesn't have to be extreme stretching.

Obviously, I'm not as experienced as you folks, but doesn't the irid coating just separate? (so rather than a solid layer of irid, it flows and just "breaks up"). Can't see how such a thin layer would affect the integrity of the glass...

Dana W.

Dana,
Dairy Queen does a lot of high temperature work. So it is not certain whether the temperatures are creating the incompatibility.
The thin film of irid is unlikely to cause incompatibilities.

I think we first must define what "non-compatable" really means and how it differs from "incompatible."

If she's talking about cracks appearing in the dichro/irid coating, that's normal, as Brock says it's similar to what happens with metal foils on glass. It's happening because the metallic coating doesn't continue to thin and move with the glass. These coatings aren't mixed into the glass, they're lying on top of it and tend to break loose, shift, float, and crack rather than stretch with their original piece of glass. I've never attributed that process to "incompatibility" as we normally use the term, i.e., when two glasses don't fit together, because only the metal fractures. I wouldn't argue that it's essentially what's happening, though.

If she's talking about cracks or fractures appearing in the glass itself, it's unlikely that the coating is the cause. I don't know what would increase the incompatibility of the metallic coating at fusing temperatures, but you certainly might increase the incompatibility of the GLASS, especially if that glass has been overfired or is subject to high temperatures for prolonged periods of time, as is normal in some types of screen melts.

Nor do I understand why anyone would think it happens rapidly "in the annealing range." Annealing glass is by definition not moving very much--the fracturing of the metallic coating happens much earlier, when the glass is still hot enough to stretch and flow. One good way to see this in action is to watch glassblowers working with foils. They roll the bubble of glass onto a sheet of metal foil, picking it up and smoothing it into the surface. Then they expand the bubble (by blowing into the pipe). The foil breaks up into the very classic metal flakes as the glass enlarges (below)--it doesn't wait until it's in the annealer.

Delberta D wrote:I just did my first screen melt. not thinking, I should have grabbed the stainless steel screen out of the kiln before cooling because when you open the kiln there are shards of glass all over that popped off during cooling, they are not stuck but it is a mess and they get into the elements, then the next time you heat the kiln they will stick. I got my screens at Grainger.com but later read on the Forum that Warmglass sells screen but it isn't on the website.

Has anyone tried removing the screen before it cools? If so, at what temperature and how do you do it safely? I love screen (or wire melts) but cleaning up the explosion after is not fun. Would love to hear if there are ways of preventing the mess it leaves behind.

This is my plan for my next screen melt...I am going to take the screen out of the kiln before the glass cools enough to harden, probably right after I am satisfied with the melt. The tricky part is where am I going to put it? I think it would be hot enough to start a fire upon contact with paper and I will have to be quick so glass doesn't start popping off. SO, in watching my husband while welding, he drops just welded steel right into a bucket of water. I will have to hope it won't warp. Maybe someone has a good experienced method?

Delberta D wrote:This is my plan for my next screen melt...I am going to take the screen out of the kiln before the glass cools enough to harden, probably right after I am satisfied with the melt. The tricky part is where am I going to put it? I think it would be hot enough to start a fire upon contact with paper and I will have to be quick so glass doesn't start popping off. SO, in watching my husband while welding, he drops just welded steel right into a bucket of water. I will have to hope it won't warp. Maybe someone has a good experienced method?

Just set it on top of some fiber blanket or board. Or else use a spare kiln shelf.

That is a great idea...Thank You very much.

Just set it on top of some fiber blanket or board. Or else use a spare kiln shelf.[/quote]


I think that perhaps by dropping the wire into water the glass on the wires will get off it too - and this would be a great benefeit. Wo'nt it?

However, I do not understand how technically one is going to lift the wires/mesh while the kiln is still working....


Havi