Firing on stainless

[Rob Morey]

I need a shelf that will fit into a bathtub size kiln. I have a piece of fiberboard that I can fuse on, but I want something a little stronger so I can have the glass run down the length of my kiln. Someone told me this weekend that they have a 1" thick, stainless steel shelf in their kiln. I always thought that wouldn't work and the glass would thermo-shock. I really need the shelf, but that size of a sheet of steel is too expensive to just mess around with and it will be too heavy to put in and take out when ever, so it will have to work in a variety of conditions. What do you all think?

Thanks in advance,

Rob

[Bert Weiss]

I need a shelf that will fit into a bathtub size kiln. I have a piece of fiberboard that I can fuse on, but I want something a little stronger so I can have the glass run down the length of my kiln. Someone told me this weekend that they have a 1" thick, stainless steel shelf in their kiln. I always thought that wouldn't work and the glass would thermo-shock. I really need the shelf, but that size of a sheet of steel is too expensive to just mess around with and it will be too heavy to put in and take out when ever, so it will have to work in a variety of conditions. What do you all think?

Thanks in advance,

Rob

I don't think so. I once was at a workshop at Haystack where we rolled sheet glass from the furnace on a 1" thick stainless steel marver. After a few sheets it was totally warped. Whatever you do it will warp. Heavy stainless is expensive to end up warped.

My suggestion is to work with blanket and alumina hydrate powder. You can get a 48" wide roll of fiberfrax. Sift on the alumina and fuse away.

[Marty]

How about 2" fiberboard, the dense stuff?

[charlie holden]

There are different grades of stainless. Some will withstand fusing temperatures, some will not. Inconel is a common name for one of the high temp stainless alloys.

You could use fiber board if you support it across its width fairly regularly along the entire length. In other words it can take the weight with lots of support underneath. As far as glass running down the surface of fiber board I'm not so sure. You would have to kiln wash it very thickly or make plaster/silica molds to sit on top.

The best solution I know of, though they are expensive too, is extruded batts from Dyson Ceramics. (Batt is the British term for kiln shelf.) They are made of cordierite, I think, the same stuff as regular kiln shelves.

http://www.dyson-ceramic-systems.com/html/batts.htm

[Rob Morey]

Well, I check out the extruded batts, (thanks Charlie,) The largest seems to be around 24" and I need something around 36". I can't imagine that there is nothing like this in the states, or at least somewhere that I could go to get custom made shelves or the like. I am very leery of trying 2" fiberboard because as the glass slides down the kiln shelf it picks up the kiln wash and I have already experienced the glass sticking to the fiberboard and ripping it up. Yet I may be able to kiln wash the snot out of it and give it a try. I ain't got nuttin' to loose. Do you think that the alumina hydrate powder, that Bert suggested, would be pulled into the glass as it moved over it? I could do a layer of that as well. Another experiment I guess. I let you all know if I find something that works. Thanks for the help.

Rob

[Bert Weiss]

Well, I check out the extruded batts, (thanks Charlie,) The largest seems to be around 24" and I need something around 36". I can't imagine that there is nothing like this in the states, or at least somewhere that I could go to get custom made shelves or the like. I am very leery of trying 2" fiberboard because as the glass slides down the kiln shelf it picks up the kiln wash and I have already experienced the glass sticking to the fiberboard and ripping it up. Yet I may be able to kiln wash the snot out of it and give it a try. I ain't got nuttin' to loose. Do you think that the alumina hydrate powder, that Bert suggested, would be pulled into the glass as it moved over it? I could do a layer of that as well. Another experiment I guess. I let you all know if I find something that works. Thanks for the help.

Rob

Rob

I work on top of fiber board and blanket all the time. A coating of alumina or kiln wash will certainly help the sticking issues. Temperature is also a big factor. Try working around 1365 for kiln carving or 1420 for fusing. I often work hotter, but the cooler you can get the job done, the fewer problems you will encounter.

[Rob Morey]

Thanks for the input Bert, but I don’t think you understand what it is that I’m trying to do. I want to melt different sheets of glass and have it run down the shelf to form a single sheet. I have done this before and it is successful on regular kiln shelves. (See images at http://photos.yahoo.com/rmorey5398 and click on shelf melt.) I can only get an 8 to 10 inch sheet and I want get something longer than that. I usually fire rather high, around 1600 to 1650 and hold for an hour, so that is my dilemma. I am not sure if it would work at a lower temp, but that my be the solution and I will definitely give it a try. Again, thank you.

Rob

[Cynthia]

Thanks for the input Bert, but I don’t think you understand what it is that I’m trying to do. I want to melt different sheets of glass and have it run down the shelf to form a single sheet. I have done this before and it is successful on regular kiln shelves. (See images at http://photos.yahoo.com/rmorey5398 and click on shelf melt.) I can only get an 8 to 10 inch sheet and I want get something longer than that. I usually fire rather high, around 1600 to 1650 and hold for an hour, so that is my dilemma. I am not sure if it would work at a lower temp, but that my be the solution and I will definitely give it a try. Again, thank you.

Rob

Rob, I understand what you are doing, and do a lot of these shelf pours myself to make inclusion glasses.

I don't think stainless is gonna work since for one, at these temps it will degrade and spall...but you say you know someone who is using stainless for this, find out what grade of stainless, and if it warps or spalls.

I have always done this technique on a primed mullite shelf, and just wash away or blast away the kiln wash that sticks. You could use fiberboard with a good coating of wash and just blast off the wash afterwards.

Not knowing the end application for this work hinders me in giving you any reasonalble information, but my experience is that you need a smooth surface for the glass to roll over. It would be prime if you ended up with a glass that was ready to use once the shelf pour was completed, but with mullite, fiberboard or with shelf papers that isn't going to happen.

Your question about the stainless really needs to be addressed to the person who has used this material successfully. If the spalling and warping aren't at issue...consider the stainless. You might want to explore graphite as well.

Just some thoughts from someone who has only had successes on mullite with this technique.

[Brian and Jenny Blanthorn]

I need a shelf that will fit into a bathtub size kiln. I have a piece of fiberboard that I can fuse on, but I want something a little stronger so I can have the glass run down the length of my kiln. Someone told me this weekend that they have a 1" thick, stainless steel shelf in their kiln. I always thought that wouldn't work and the glass would thermo-shock. I really need the shelf, but that size of a sheet of steel is too expensive to just mess around with and it will be too heavy to put in and take out when ever, so it will have to work in a variety of conditions. What do you all think?

Thanks in advance,

Rob

Try this revolutionary technology

Multi Bat tm

Use more than 1 bat

Get the bats saw em up so correct size

Use some sawn up bat strips 2 support the joint 90 degrees 2 the joint

Put a number of supports in the kiln use soft clay balls under

Put everthing in carefully set up with spirit levil

Tap gently with flat wood 2 even shelves

Warm up to dry clay

Bat wash joint, wet sand the whole lot with small peice of bat

Dry off a little

Bat wash the whole lot

Dry, scrape down

Repeat till got perfect 'new ' shelf

This should act as a whole shelf n the joint should not open

Try n fire low n soak rather than go hoter

Patch up as necassary

[charlie holden]

Well, I check out the extruded batts, (thanks Charlie,) The largest seems to be around 24" and I need something around 36". I can't imagine that there is nothing like this in the states, or at least somewhere that I could go to get custom made shelves or the like. I am very leery of trying 2" fiberboard because as the glass slides down the kiln shelf it picks up the kiln wash and I have already experienced the glass sticking to the fiberboard and ripping it up. Yet I may be able to kiln wash the snot out of it and give it a try. I ain't got nuttin' to loose. Do you think that the alumina hydrate powder, that Bert suggested, would be pulled into the glass as it moved over it? I could do a layer of that as well. Another experiment I guess. I let you all know if I find something that works. Thanks for the help.

Rob

Email or call the US office of Dyson. I have a quote from them, though I haven't scraped together the scratch yet, for an extruded shelf 1575 x 800 x38mm. That's 62 x 31 1/2 x 1 1/2 inches. The width is the limiting factor. They can just keep extruding it out for very long lengths and cut it off when it is long enough. The longer it is, the less flat it may be.

Meanwhile, I've written this before but there seems to be some resistance to it -- plaster/silica and maybe a little zircopax (2:2:1 by weight). It's the best surface for moving glass, even when it cracks. You can wash any that sticks off with a plastic bristle brush. Any loose powder will definitely be eaten by the glass. Fiber paper too.

You can make big flat plaster surfaces by building a low dam on a level surface, 1/4 inch or so, fill it with wet plaster/silica. (It will likely have to be poured directly onto the kiln shelf since these things are hard to move.) You can flatten the top surface by screeding it when it's wet and/or scraping and sanding it when it's dry. This is a good oportunity to carve in texture. Another method is to lay a piece of float glass on top of it wet, (coated with a release like vaseline). Lay one edge of the glass down first to squeeze any air bubbles out the other side as you lay it flat.

[Cynthia]

Thanks Charlie for the info about the extruded shelves and the especially for the formula for a skim coat of sorts. I am very interested in both. I have a magnaform shelf for my Denver and it's fine except it's unifrax and I have to use Thinfire...also will warp a bit over time.

When it comes time to replace I will check out the extruded shelf. Is it hollow by any chance? Is this the honeycomb shelf?

I will check out their site. Thanks again.

[Rob Morey]

Hey Thanks Charlie. I'll contact Dryson. I am interested in the plaster/silica as well, but what is zircopax? Where would I find it and what does it do?

Rob

[Becky Bergsma]

Western Industrial Ceramics, near Portland, sells an extruded board called Magnaform, not cheap, various sizes and they will rigidize it for you. Talk to Alison, very helpful 503-692-3770

Becky