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s/steels rings

Posted: Thu May 30, 2013 5:26 pm
by Paul Schulz
hi guys some thoughts on s/steel rings please. i am thinking of cutting my 21 cm ring on one side to help with expansion and contraction. i know thick kiln paper would work but i'm not able to get any in NZ ,so would use a few layer of thin paper and a hacksaw cut on one side of the ring,,has any one tried this ,, some thoughts please..and as always many thanks

Re: s/steels rings

Posted: Thu May 30, 2013 6:39 pm
by Brock
Try Claudia Borella in Wanganui. She may have fiber paper.

Re: s/steels rings

Posted: Thu May 30, 2013 6:51 pm
by Bert Weiss
A couple of layers of thin paper should do the trick. Worst case is that the ring holds on to the glass. If that happens, set the glass on a brick or something, heat the glass to around 300ºF (150ºC), and if the ring doesn't fall off, reach in and help it to do so. Then use another layer of thin paper. I much prefer thin paper to thick. You basically pay by the pound, so in the long run, the thin can cost you less if you figure out just what you need. When it comes to kiln carving with the thin papers. the glass will clearly read the bump from one layer. Here in the USA, thin paper is 1/32" thick (.8mm)

Re: s/steels rings

Posted: Thu May 30, 2013 7:39 pm
by Paul Schulz
hey thanks guys i'll try using 3 layers of the thin,,,i take it that putting a cut in the ring is not going to work

Re: s/steels rings

Posted: Fri May 31, 2013 2:03 am
by Kim Manley
Or try Bluedog glass in Melbourne. Brenda may be able to post some to tou in a postal tube. There is a web site.

Re: s/steels rings

Posted: Fri May 31, 2013 9:49 am
by Eric Baker
Hi Paul,

cutting the ring can be made to work. It's just that the fiber paper is much easier, and much less destructive.

You could probably cut the ring and place kiln bricks, or some other weights, around the edge of the ring to hold it together during firing. Or you could weld on a nut and screw fixture and make essentially a 'hose clamp' type apparatus that would be easy to open after firing, and re-tighten to close the ring before the next firing. Or maybe there are hose clamps readily available in industrial/retail places near you, and all you have to do is find one that will fit around the stainless ring.

There are probably several ways to approach the project, but again, the fiber paper is just simpler and less destructive...

warm regards,

Eric

Re: s/steels rings

Posted: Fri May 31, 2013 5:46 pm
by Paul Schulz
thanks guys so the info ,,,looks like i just use the thin paper,,,although i may look at cutting a ring some day,,,,i'm, sure there are some ideas to explore there sometime

Re: s/steels rings

Posted: Sat Jun 01, 2013 8:03 am
by David Jenkins
Dammit! Have you just given me yet another variable to worry about in doing fused glass work?

I would have thought that the thickness of the ring was so small compared to its radius (and hence the glass inside the ring), that the linear differences due to thermal contraction/expansion of the differing materials would be insignificant. And further, that the differences in COE of glass vs. stainless would militate against any kind of problems caused by contraction/expansion (in the warm glass context). Not true?

I'm curious as to what you're doing where the expansion/contraction of the ring itself affects the final outcome?

[Bonus question for puzzle lovers (this one's kicked around for years and years): What happens to the inside diameter of a ring of pipe when it's heated or cooled? If you don't know, think about it for a while before looking up the answer elsewhere.]

Re: s/steels rings

Posted: Sat Jun 01, 2013 10:30 am
by Bert Weiss
David Jenkins wrote:I'm curious as to what you're doing where the expansion/contraction of the ring itself affects the final outcome?

[Bonus question for puzzle lovers (this one's kicked around for years and years): What happens to the inside diameter of a ring of pipe when it's heated or cooled? If you don't know, think about it for a while before looking up the answer elsewhere.]
Every material expands when heated and contracts when cooled. Most materials do this at different rates in different temperature ranges. We in the glass world are hyper sensitive to this. Considering that .0000006 cm squared is enough difference for 2 glasses to break apart, it doesn't take much.

Re: s/steels rings

Posted: Sat Jun 01, 2013 12:13 pm
by David Jenkins
I probably wasn't clear - I thought the original question had to do with the expansion/contraction of the steel ring itself. Wouldn't you have to have glass that fit very,very, tightly inside the ring to start with, before the contraction of the ring as it cooled caused a problem?

That is, the diameter of the ring opening would expand/contract very little, due to the small thickness of the steel. A 10" 2-layer glass blank might expand ... what? maybe a few hundredths of an inch?

Re: s/steels rings

Posted: Sat Jun 01, 2013 12:25 pm
by Bert Weiss
David Jenkins wrote:I probably wasn't clear - I thought the original question had to do with the expansion/contraction of the steel ring itself. Wouldn't you have to have glass that fit very,very, tightly inside the ring to start with, before the contraction of the ring as it cooled caused a problem?

That is, the diameter of the ring opening would expand/contract very little, due to the small thickness of the steel. A 10" 2-layer glass blank might expand ... what? maybe a few hundredths of an inch?
If you fill a ring at room temperature with glass and then heat them both to fusing temperatures, the ring will contract more than the size of the glass and hold on to it quite firmly. This is also true if you heat the glass enough to flow out to fill the ring. The thickness of the fiber paper will mitigate this. I have rings that I line with fiber rope and then fill with large frits and fuse. This works well for me because the rope is relatively durable so I get many uses from one piece. Papers are a one shot deal. The rope is also a good profile to minimize needling. I also work with spherical shaped molds that are kiln washed. This mold will hold on to the bowl slumped inside strong enough so that the glass will not fall out when inverted. If I heat them both to around 300ºF with them both inverted, the glass will fall out. This is all due to the differences in how the 2 materials expand and contract in different temperature zones. The glass stabilizes it's solid shape relatively hot, and then expands and contracts from that point on. The steel has a different profile of how it changes through the temperatures up to fusing.

I also have a ss ring that I use for drop slumps. If I work relatively shallow, I have no problems. If I slump deeper with no lining, the steel will crack the glass as it cools. With a fiber lining, it will work OK.