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I have a 2.1cm thick (7 layers of Bullseye glass) x 25 cm long and 8 cm wide piece I would like to slump over corrugated iron so it stands up by itself. I wonder if just coating the iron with kiln wash will work or should I use fibre paper instead? Does anyone out there have experience with slumping over iron? I have not tried it before. Thanks.

If you use kiln wash, the iron will spall and get all over your piece. Use fiber paper or thinfire shelf paper instead.

I would also do a test first, rather than experiment with a piece you really care about.

Is your corrugated mold "iron" like cast iron, or is it corrugated steel roofing material?
Please make sure that it doesn't have a galvanized coating on it if it goes in the kiln. The fumes from burning zinc are VERY toxic. And who knows what kind of residue it will leave in the kiln to contaminate subsequent firings.

If you're already sure that your mold is uncoated, then please disregard this post.
I just don't want anyone to get hurt...



Steve

Jo-AnneMaire wrote:I have a 2.1cm thick (7 layers of Bullseye glass) x 25 cm long and 8 cm wide piece I would like to slump over corrugated iron so it stands up by itself. I wonder if just coating the iron with kiln wash will work or should I use fibre paper instead? Does anyone out there have experience with slumping over iron? I have not tried it before. Thanks.

I did it only once and what a mess!!! I would use fiber paper as Brad suggest but you my lose some of the texture your looking for.
Good luck!!

Just to reinforce what Suds said.......make absolutely certain it's not coated with zinc. Here in Oz corrugated 'iron' is part of the architectural landscape. It's coated with zinc to prevent , or delay, rusting. I looked into using it as a mold, too, but was advised against doing so.

I can't imagine any company producing corrugated roofing material, which it's mostly used for, without galvanizing it.

Perhaps you could make a mold from the corrugated iron out of some kiln-friendly material. That's how I decided to resolve the problem. Didn't do it yet, but it's on the list. Jen

Thanks for all your advice guys. I assume that the corrugated iron I have is galvanised, so you just saved my kiln (and perhaps me too)! I will see what else I can find for a mould.

you can use what you have to make a mold with clay, or wet felt (fiber blanket with rigidizer), or that mold mix that Mike Dupille sells (which has a name that has flown right out of my head).

Cheryl wrote:that mold mix that Mike Dupille sells

Castalot.

Brad Walker wrote:

Cheryl wrote:that mold mix that Mike Dupille sells

Castalot.

304 stainless steel, or wrinkled fiber blanket. You can take stainless steel or black iron tubing and drape 1/4" fiber blanket over it. Unfortunately I don't know any sources for less than a full case of Unifrax 1/4" Durablanket. This is a really good solution, if you have some.

Thanks for all the suggestions guys. I think I'll try the fibreblanket with rigidizer. That sounds like a great way to make molds. I'll let you know how it goes.

Jo-AnneMaire wrote:Thanks for all the suggestions guys. I think I'll try the fibreblanket with rigidizer. That sounds like a great way to make molds. I'll let you know how it goes.

Why use rigidizer? This creates more problems than it solves. Rigidizer must be kilnwashed. It doesn't really end up being rigid and strong. Simply draping blanket is so much simpler, and is totally reusable. I like to powder my blanket with alumina hydrate, but this is not necessary at slump temps. I much prefer blanket to paper because it is so much stronger making it durable.

Bert you forgot to add that rigidizer takes foreverto dry with a bonus of the final item being made brittle and fragile enough to easily sustain damage.
terracotta clay will make a much better longer lasting mold.