Bottomless Molds - traditional slumping method?

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Deive Butvila
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Bottomless Molds - traditional slumping method?

Post by Deive Butvila »

Has anyone ever used bottom less slumping molds?

I am wondering how heat escapes from these bottomless molds that sit directly on the kiln shelf, and if there are any special firing considerations. I don't see anything on the seller's web site about needing to do anything special with these molds.

The only slumping molds I own all have heat escape holes in the bottom. I put these on short kiln posts when slumping. All very straightforward.

Thank You
Valerie Adams
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Re: Bottomless Molds - traditional slumping method?

Post by Valerie Adams »

I'm guessing you're talking about Laurie Spray's molds. She will supply detailed firing schedules for you to start with. Most of her molds are fairly shallow; I've got one that I just use as I would any other. Many of my shallow molds don't have holes drilled in them anyway. But I'm a big advocate of 'low and slow' for my slumping.
Laurie Spray
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Re: Bottomless Molds - traditional slumping method?

Post by Laurie Spray »

We have been making our "Bottomless Molds" for almost 10 years now. They are fired just like you would any other slumping mold but you are guaranteed to always have a non rocking floor to your glass creation when using them. I got very tired of rocking bottoms on art pieces that were slumped onto molds that were basically made for the ceramic industry......and then just renamed glass slumping molds. We now make these molds from 4" to 18". Along with Valerie.....low and slow is the best way to slump.....but you can also slump and fire polish at the same time in low profile molds. Let us know if you have any questions.
Laurie Spray

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Maker of stainless steel rings,pattern bar formers, pot melt pots, and Bottomless Molds
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rosanna gusler
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Re: Bottomless Molds - traditional slumping method?

Post by rosanna gusler »

The holes are to allow air to escape. Not heat. R.
artist, owner of wanchese art studio, marine finisher
Deive Butvila
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Re: Bottomless Molds - traditional slumping method?

Post by Deive Butvila »

rosanna gusler wrote:The holes are to allow air to escape. Not heat. R.
Yes, thank you for the correction.
Deive Butvila
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Re: Bottomless Molds - traditional slumping method?

Post by Deive Butvila »

I guess I did not realize these are shallow low profile molds so not having vents makes some sense to me. I just have not had any experience with ventless molds.

Thanks to all for educating the newbie!
rosanna gusler
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Re: Bottomless Molds - traditional slumping method?

Post by rosanna gusler »

The fact that they have no bottom means that yes they are vented. Air can escape between the mold and the shelf. If it will not hold water it will not hold air. R.
artist, owner of wanchese art studio, marine finisher
Morganica
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Re: Bottomless Molds - traditional slumping method?

Post by Morganica »

Just think of those center holes as great big vents... ;-)
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