Sheet metal for slumping molds?

quill · Post by **quill** » Thu Nov 20, 2003 1:16 am

I am saving up for a bigger kiln & am lready planning out some projects & was wondering...

I am using sheets of steel on my work table to protect them when I teach beadmaking.

If I cut & made gentle bends in it is there any reason I could not use this material for slumping onto?

I have a design in mind I would need to make my own mold for.

Has anyone tried this?

rosanna gusler · Post by **rosanna gusler** » Thu Nov 20, 2003 7:38 am

it will work fine as long as the steel is not galvanized. i have a local metal shop make molds for me. they use alot of stainless so that is what we dig out of the scrap bin. i make what i want out of cardboard and mark the on edge shape on a grid. they have the tools. i almost have them convinced to let me play with the brake. rosanna

Phil Hoppes · Post by **Phil Hoppes** » Thu Nov 20, 2003 9:49 am

Sheet steel is ok. It tends to spall and you need to cover it with a fair amount of kiln wash because of this. If you can use stainless steel it is much better.

Phil

Tony Serviente · Post by **Tony Serviente** » Thu Nov 20, 2003 11:14 am

I might use steel for a onesie test, but for daily work I stick with stainless. The amount of oxidation on regular steel is hard to deal with. There would be so much form maintenance that it wouldn't be worth it to me. A good local metal shop should be able to do most stainless fab work you might need. You should also check out a commercial kitchen supply store. You'll find lots of relatively inexpensive stainless objects, some of which make cool forms for glass work.

rosanna gusler · Post by **rosanna gusler** » Thu Nov 20, 2003 3:00 pm

commercial kitchen supply. find the local guys that do the stainless walls and counters for restaurant kitchens. they throw away tons of scrap sheet. they can also make stainless do tricks. if they do recycle they will probably be glad to sell it to you at a cheap price. then they do not have to transport. scroungergirl

Cliff Swanson · Post by **Cliff Swanson** » Thu Nov 20, 2003 6:15 pm

I had a local shop make me a mold out of 1/4 plate steel, not stainless. Mine is a 14x14" square, rolled in a continuous radius to a depth of 1.5" below the edge at the lowest point. I sandblasted it on both sides, but only covered the glass-facing side with kiln wash.

I've just finished making about a dozen 6x9" arc shaped sushi plates footed with marbles. I had no trouble with it crazing and shedding onto the kiln shelf through all the firings (2 plates/firing), and I actually had used it for other pieces prior to all of this without re-blasting or kiln washing in between.

I paid $40 for it, and had it the day I called to see if it could be made.

Cliff

Tony Serviente · Post by **Tony Serviente** » Thu Nov 20, 2003 6:20 pm

That's great Cliff. I'd wonder what's different about your steel. Did you get it from a commercial steel supplier, or from a small shop. Stuff I've used was from a supplier to the welding/fabricating trade, and it required stripping and re washing every firing.

Cliff Swanson · Post by **Cliff Swanson** » Thu Nov 20, 2003 9:27 pm

Tony... I don't know that there is anything special about the steel. I asked for 1/4" plate, and that's what the receipt they wrote indicates. The shop is a moderately sized operation that is known for it's industrial fabrication skills locally. It's one of those business operations that runs quite well on word of mouth referral, little-no advertising. They are always busy, nonetheless.

Cliff

Tony Serviente · Post by **Tony Serviente** » Thu Nov 20, 2003 9:36 pm

Was thinking that you might have gotten it from a shop that specialized in, say, aircraft work, and it might have been a different alloy. I have used sheet, angle, and bar steel (up to 1/8") all with the same poor result, but have never used 1/4" plate. Wonder if it is thickness that makes difference, and if so why? Can't imagine it is a thermal issue with the conduction of steel being what it is. Have to ask my mettalurgist friend as my guess at this point is that theres no significant difference in the steel.

Brock · Post by **Brock** » Thu Nov 20, 2003 9:37 pm

We've left many molds like Cliff's in studios around the country. We normally get a 22" square, 1/4" plate steel, rolled or English milled as Cliff describes. Sandblast it at as high a pressure as your system will deliver, 80 - 120 psi, heat to 300F, or so, spray with kiln wash. Mine is at least 10 years old, probably more. The bottom spalls, but not the slumping surface.

quill · Post by **quill** » Sun Nov 23, 2003 10:52 am

Wow!
Thanks for all the tips. Looks like I have some fun ahead.

Tony Serviente · Post by **Tony Serviente** » Sun Nov 23, 2003 11:08 pm

Thanks for elaboration Brock.Wonder if the sandblasting is the key, and if it gives enough tooth for the wash to act as an oxide shield, like an ersatz version of stainless. When things slow down I'll try it again.

Marty · Post by **Marty** » Mon Nov 24, 2003 9:28 am

Tony- it's not the sandblasting, it's got to be either the steel itself or the thickness. Sandblasting just gives it tooth for the kilnwash. My attempts at sheet steel molds all led to spalling quickly; the steel was less than 1/8" thick (I just can't seem to get the guage concept to stick in my head).
Marty

Tony Serviente · Post by **Tony Serviente** » Mon Nov 24, 2003 12:24 pm

Marty-Glad you experienced same thing I have. Was beginning to think my steel monger was selling me the stuff not fit for making trivets for K Mart! Cliff and Brock have had success with the 1/4 inch, which brings me back to my wondering what is up with the thicker steel. I kiln washed the 1/8 inch and under with same problems as you, though I did not sandblast first. I would have thought that the 1/4" was the same composition as the thinner. Going to call the steel man later and find out.

Brock · Post by **Brock** » Mon Nov 24, 2003 12:27 pm

Tony Serviente wrote:Marty-Glad you experienced same thing I have. Was beginning to think my steel monger was selling me the stuff not fit for making trivets for K Mart! Cliff and Brock have had success with the 1/4 inch, which brings me back to my wondering what is up with the thicker steel. I kiln washed the 1/8 inch and under with same problems as you, though I did not sandblast first. I would have thought that the 1/4" was the same composition as the thinner. Going to call the steel man later and find out.

Good luck with it Tony, I have had great success with 1/4" all over the US. Let me caution you however, that at 1700F, 3/16" plate steel will slump flat. Not too good for the glass on it either! Brock

Marty · Post by **Marty** » Mon Nov 24, 2003 11:01 pm

Brock- slumping at 1700F?!?!?!! Muy Macho!

Brock · Post by **Brock** » Mon Nov 24, 2003 11:10 pm

Marty wrote:Brock- slumping at 1700F?!?!?!! Muy Macho!

Si! Cojones of graphito! Ah, but mi amigo, it was inadvertent. Brock