float glass in the kiln ?

[Brian Newman]

I want to try this and I wonder if it is a new idea.
Arrange compatable sheets of stained glass ontop of tin in a crucible and fire it into a a single piece of float glass.
Has anyone ever heard of someone doing this?
Any hints or tips?

[Greymatter Glass]

well... seems impractical at the least. Toxic fumes, molten metal in the kiln, no controll over atmosphere... the tin would probably just oxidize and burn off by the time the glass melted.

I know it's how they do it in big factories, but I think there' more to it than just an uncontrolled melt of tin and glass together....

My question at this point is: What's your final purpose for doing this?

If you're looking for thick pieces of glass try Blenko or Bullseye billet glass. Also, there's no reason to go through a ton of tests to find 2 sheets of compatible "stained glass" glass... Bullseye and Spectrum both offer tested compatible glass made for fusing (bullseye with bullseye, spectrum with spectrum, you can't mix the two) The money you would spend finding 2 compatible sheets of stained glass would pale in comparison to the extra cost of "tested compatible" glass from Bullseye.

If your goal is to get a thick sheet of glass thats smooth on both sides you might just look into running a full fuse then polishing the matte side of the glass with a recipri-lap or by hand with SC abrasive and diamond polishing pastes, or a cerium oxide buff. Your top side should be flame polish smooth. You can use silicacarbide kiln shelf cut into dams to keep the melt contained, but make sure you coat them with kiln wash or the glass will stick to them. back them up with kil;n brick if you're going thicker than an inch, and dont forget to take the dams into account when annealing.

If you poke around Bullseyes website long enough you'll find their tech notes section, lots of good advice there for this type of glass.

-Doug

[Udai Hussien]

I agree with doug, the lead solder would definatly make a big stink

[Greymatter Glass]

Who said anything about lead? I assume he means new stained glass, not old recycled crap.

Right?

-Doug

[Udai Hussien]

Oh I was just talking in general, I really know very much about staiuned glass, i thought thry used lead solder... i asppologize i i am wrong

[Brian Newman]

I meant using known compatible glasses, like you said, and making picture windows without the solder.

[Greymatter Glass]

Oh, then why would you float it on tin? Just fuse it as you normally would. I'd put the color on top of a clear sheet and tack fuse if you want really crisp lines. If you do just color you'll need to go to a full fuse which would distort your lines somewhat.

The problem I can tell you you'll run into is building codes do not allow for un tempered sheet glass on external applications, so you'll have to build a frame around the window and put tempered glass on the external face. It's a good thing to do in any case as it protects your artwork.

-Doug

[NUBBLET]

Lead can also be in glass .

[Julian]

Well, no need to go all psycho with tin and what not to do fusing.
A good internet resource is www.warmglass.com if you want to talk about fusing and look at advanced artist's work.

[Brian Newman]

But can you slump it smooth? Like float glass?

[FredLight]

Depends on what you mean by that. Slump means to bend without stretching. Take a look at WarmGlass.com. If you mean plate glass flat then, no. You'd have to grind one whole surface for that to happen.

Boyce Lundstrom's books (Glass fusing 1&2) would be really good for you right now. They cover this topic quite sufficiently.

Doug's suggestion about tack fusing to clear has worked accurately for me many times in the past, though I didn't learn it from him.

While I do wish you luck, expect a long period of experimentation and "figuring it out" to get this to come out right. It's much like asking how to do stick stack, reversal, montage piece and getting it right on the first try.
Work your way up. Make 4x4" tiles first, then slump them into ashtray molds. Keep working your way up, until you have a feel for it.
My last "large" project was a 24" diameter X 1 1/4 inch thick blank, slumped 6" in the center.I had to do about 20 practice runs. I had three kilns running simultaneously, so it only took about 10 days. Write it all down and note any mistakes or flaws, so you can avoid them at each subsequent try. Fusible glass isn't cheap, and the heat up times are longer, so mistakes are expensive and time consuming.

[Greymatter Glass]

Oh, yeah, I learned from Lundstroms books as well, and from my mom and the store she works at (Hot Flash Glass, in Albuquerque)

Fusing is fun, it's a much slower pace than lamp working, and more satifying to me than stained glass. It doesn't take much time or effort to hand polish the matte side of a 4x4 inch tile, less than an hour. I use the little sponge rubber backed diamond plishing pads from Wale, dunno what grits they are, just have them labeld 1, 2, &3, then use a chamois leather pad and cerium oxide for final polish.

How large a window do you plan to make? If you dont have much (or any) experiance start small, 4x4 is where I'm starting, and after a half dozen projects I'm ready to go bigger and thicker.

Screen printing on glass is fun :)

-Doug

[Brian Newman]

I still wanna try.
What should I use for a crucible? I already have a graphite crucible, 5" by 9" I think, but it burns a bit every firing.
where do I get my tin?
which brand of fusing glass do you suggest?
ceramic fiber paper should work at the edges.

[Greymatter Glass]

I'm not gonna stop you... good luck.

I'd get tin from a metal supplier, look in your local phone book. I really don't know what kind of crucible you'd need to use. Graphite works for melting metal, but in an oxidizing atmosphere you'll get graphite flakes breaking loose and floating up to the top and getting trapped between the glass and tin. Normally Graphite Crucibles are used _ONLY_ in atmosphericly controlled ovens (i.e. sealed and sometimes backfilled with forming gas) or in an induction furnace. I don't know what kind of reaction you can expect from the rapidly oxiding tin, the grpahite breaking down as it absorbs that oxygen, and the impurities produced. If you want to do it right you'll probably have to refine your tin before use with silica sand and a quartz or graphite rod, and plenty of borax or boric acid flux (there's a very fine line when fluxing for refining, too little and you leave impurities, too much and you'll melt the impurities in and ruin the melt) but i really can't say for certain what impurities would do, if anything.

I'd suggest a fused silica or alumina zirconia crucible for melting the metal, but both will have to be lined with either hydrated alumina or kilnwash to prevent the glass from sticking to the sides. I don't think Fiberpaper will work only because I'd be worried about any wicking effect, or other reaction with, the tin.

Also, what kinf od crucible do you have... is it solid graphite or graphic ceramic (looks flakey) and what is it made for... 5" diameter and 9" deep? or 5x9 wide and how deep?

Also be sure you have plenty of powerful ventilation, I'm sure tin fumes aren'ty good for you, and there's a slight chance you'll either boil or ignite the tin.

If you want a certain color of glass that's smooth on both sides I'd just call Bullseye and see if they can roll a custom sheet for you.

Also, if you go the fusing route, I'd practice with some regualr (cheap) stained glass in single sheets before you move into floating glass. You'll have to pre-fuse any sheet you want to float anyways if they're going to be cut from multiple sheets, so maybe just try that and see if it will work for you.

Also, be mindful that you're putting a lot of metal into your kiln.... if anything happens, like the crucible cracks, or the kiln gets bumped, and liquid metal spills out it will leave the kiln. Unlike glass it will not just seal up any little openings it finds, it will continue to conduct heat and will seep into every little nook and cranny it acan find, so make sure your kiln is not only on a safe surface, but that everything below and around is also protected. If possible do the whole thing out doors on a concrete slab.

Let us know how it goes...

-Doug

[Brian Newman]

The crucible is solid graphite I would guess 4" deep 5" wide and 9" long. It is already starting to burn from slumping 4 beer bottles into a step surface for a schoolbus. I can get good deals on graphite odditys and such from speer Canada here in Kitchener by digging through their scrap bin.(4 bucks Canadian per pound last time I went 3-4 years back.) Got a 24"x18"x1/2" slab at that price.

[NUBBLET]

From what I have heard and experienced graphite will decay very quickly in a kiln , I think it may work if it was high enough quality and could handle say 3000 degrees F . Somewhere there is a thread with links to crucibles and refractory stuff , you could always get the specs of what they are made from and see if you can fashion one cheaper (if concerned with cost) or find a local or semi local supplier . I say good luck , in theory it sounds possible , although for boro you may have to find a different metal to float on , one that will become molten but not boil at the temp needed for boro and also be more dense than boro to float and not sink ( I would think) . You can get density specs on manufacturers websites usually , I know from Kimble you can . Of corse you are wanting to try it with soft glass I believe , so you do not have that issue .

[FredLight]

Yeah, try it, but skip the tin part.
Factories that float glass on tin are doing it on a large scale. The tin is molten before the glass gets to it. I'm sure they skim it too.

The worst part about tin for me is the devitrification. Me No Rikey.

All I really want to say is be careful, this sounds hazardous to me.

[Brian Newman]

might skip it. Just playing with ideas at this stage.