Slumping small and large projects together

[Maggie Abdel Rahman]

Hello
I would like to slump glass projects of different diameters - ranging from 20 to 45 cm together in one kiln. I have slumped only small pieces one by one in a smaller kiln. Now I would like to load a larger kiln to slump previously fused pieces. Is this feasible ?

[Terry Gallentine]

It all depends on the complexity of the molds, the depth of the molds and the types of glass used.

[Maggie Abdel Rahman]

The depth of the molds vary from a simple square plate to bowls 12 cm deep but they have fairly simple shapes. I am also draping glass over a vase and I used float glass previously fused with ferro enamels.

[Bert Weiss]

There is a point at which you have heated the glass too much and it will begin to fall down the sides of a mold. Until that point, the glass will slump or drape, until it hits a solid surface.

Float glass is far more forgiving than the fusing glasses. I often fire float glass in bowl molds as hot as 1420ºF. They come out as bowls.

[Maggie Abdel Rahman]

Many thanks Terry and Bert. have a nice weekend !

[DonMcClennen]

Trying to slump shallow and deeper shapes as well as draping all in same firing is asking for failure. The best way to control what's happening in your kiln is to forget about mass production and program each firing to best suit each individual piece. Quality over quantity!

[Maggie Abdel Rahman]

I am trying to save time because I am participating in a big event in March. Slumping piece by piece is a luxury, but thanks for your advice.

[Maggie Abdel Rahman]

On a second thought, I did all draping together, and will do the slumping separately. Don's opinion was supported by many colleagues- and I will post photos.

[Bert Weiss]

On a second thought, I did all draping together, and will do the slumping separately. Don's opinion was supported by many colleagues- and I will post photos.

I think this is a good strategy. Draping is not always supported, so the glass can keep on stretching and sagging. Slumping in to a mold is different. As I said, the challenge is to not fire so hot that the glass continues to fall after it is fully supported. Float glass is far more forgiving in this than fusing glasses.