Using a slump other than SS

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Anne Marie Flaherty
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Joined: Wed Dec 12, 2012 1:06 am

Using a slump other than SS

Post by Anne Marie Flaherty »

What happens if I try and slump over a non SS bowl? have this really cool metal covered bowl but I'm sure it's not stainless, can I try it with out damaging my kiln?
Morganica
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Re: Using a slump other than SS

Post by Morganica »

Depends on the metal. Often SS is marked, so check first. If not, pot metal, pewter and/or aluminum are the ones to really watch out for. Pewter melts as low as 435F, aluminum melts around 1220F, most pot metals go around 770F or something--slumping glass in the 1300F range obviously is going to turn bowls made of those metals into a puddle. I've never had melted aluminum damage the kilnshelf, but it marks it up, makes a mess and leaves a residue.

If a magnet is attracted to your bowl, it's iron or steel and you're probably OK. Fire it to just past your slump temperature to see if it spalls (spits great black flakes that get into everything). It'll turn dull black/blue, but if it otherwise stays intact, it's good.

Stainless steel isn't always magnetic, so the magnet isn't a reliable test if it doesn't attract. Aluminum feels a bit warmer, is much lighter in weight, makes a duller sound when you thump it, and is softer so scratches and bends more readily than stainless steel. If you can't tell those things, put it in sand in the kiln and take it to about 1300F. The sand will help contain it if it melts, and keep it from damaging your kiln.
Cynthia Morgan
Marketeer, Webbist, Glassist
http://www.morganica.com/bloggery
http://www.cynthiamorgan.com

"I wrote, therefore I was." (me)
Anne Marie Flaherty
Posts: 10
Joined: Wed Dec 12, 2012 1:06 am

Re: Using a slump other than SS

Post by Anne Marie Flaherty »

Thanks for the suggestions. I have a feeling it's some sort of clay covered in a cheap metal glaze. Wish me luck!
Morganica
Posts: 1079
Joined: Mon May 19, 2003 6:19 pm
Location: Portland, OR
Contact:

Re: Using a slump other than SS

Post by Morganica »

Anne Marie Flaherty wrote:Thanks for the suggestions. I have a feeling it's some sort of clay covered in a cheap metal glaze. Wish me luck!
Clay with a metal glaze? I'd go find another bowl. Too many variables--that could be paint or enamel, or a metal luster that could outgas and contaminate the kiln, the clay might not be fired pottery but something else...
Cynthia Morgan
Marketeer, Webbist, Glassist
http://www.morganica.com/bloggery
http://www.cynthiamorgan.com

"I wrote, therefore I was." (me)
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