Making Glass Bowls – Molds and Techniques Advice Needed

[agf]

Someone has asked if we could make glass bowls – something we have not done before. These are various sizes, 24″ to 48″ in diameter and the height is about 1/3 the diameter. These start in the middle pretty flat and the radius increases until the edge is near vertical. Glass to be 1/2″ thick and there is to be a small hole in the center. While we have ovens that can handle this size, and working out the temperature, etc. to slump is fairly straight forward, I am struggling with how best to make a mold for these shapes. Any advice would be appreciated.

[Anonymous]

The steep edge is the characteristic that makes this difficult. Most deep/steep slumps are done using a series of slumps where each mold is progressively more sloped and deeper than the previous.  This has the benefit of allowing you to adjust positioning along the way to the final shape.

You can see an example of a mold set specifically for this purpose on page 49 of the Bullseye catalog (downloadable here: http://www.bullseyeglass.com/bullseye-catalog.html).

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Paul
FusedGlass.Org
Helios Kiln Glass Studio
PaulTarlow.com

 

[agf]

Paul,

Given a drawing of the shape, 48″ diameter with a 18″ drop, where do I get such a mold? Or how do I make one? Plaster and clay seem out of the question due to size and handling. Stainless steel would be good but who can fabricate one? Perhaps a fiber blanket mold with ridizier. Has anyone tried something this large?

Marshall

 

Marshall

[Anonymous]

At that size rigidized fiber blanket probably would not support the weight without splitting.

 

I would seek out a potter to make what you want. You can achieve the multi step firing with a single mold by filling it with various amounts of dry plaster for the initial slumps.

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Paul
FusedGlass.Org
Helios Kiln Glass Studio
PaulTarlow.com

 

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