Tools: Slumping mold templates

Awhile back I noticed that I was passing on a lot of shortcuts and tricks that I’ve learned from many people over the years, on places like, in this blog, and in classes. I’m in the process of building out a new website that will collect this stuff into a some reasonable order, but for now, I thought I’d start getting these things posted and classified.

Right now I’m thinking of dividing this stuff into five areas: Studio storage, fusing, casting, tools and testing. And I’ll be creating a space for it at the bottom of the home page, to make the collection a bit easier to find. This is the first of many; please let me know if you have suggestions for improving it (or want me to answer a particular question).

Slumping mold templates

You’d think cutting a piece of glass to slump would be as simple as dropping the mold upside down on the glass and tracing the shape. Sometimes it is, sometimes not…but even if that works it can be helpful to know what you’re tracing over.

Most people make a paper template of a mold; I bought a roll of transparent polypropylene sheet and use that instead. I can cut an exact (and durable) pattern for a particular mold and also outline edges, slopes and bowl bottoms. The clear template can move around on a sheet of patterned glass until I get it in just the right position.

It’s great for cutting the raw glass, but it’s even better for marking position after the blank is fired since it lets me compensate for components that might have shifted in the kiln. I can also jot down notes right on the template, so I can record a favorite variation or a caution about mold peculiarities.

In a pinch, you can also just use a clear sheet of glass for this–that’s what I’m doing in the picture above. Just stick the glass on the mold and draw in the shapes with a Sharpie marker. I frequently do that with new molds, so I can see (and adjust the real template for) any compensations that need to be made for that mold.

Disclaimer: I doubt I invented any of this; some is pretty obvious and the rest probably originated in Mesopotamia or something. If you know of an even smarter tool, please, please share!


3 thoughts on “Tools: Slumping mold templates”

  1. some molds aren’t symmetric, and thus if you place the mold upside down on the glass to trace around and you didn’t flip the glass upside down, the glass won’t fit the correct way when you try to fit the glass to the mold for slumping. damhikt.

  2. Chaniarts, this is very true, and early on I had that bite me a couple of times. It’s also a problem when the mold is wide-lipped and performs best with the glass actually seated inside.

  3. I bought 10 different size acrylic circles (bullet proof ). That started out at 2.50 for a six inch and 5.70 for a fifteen inch. I had them specially sized to match my round molds. Thank you very much for the suggestion .

    If anyone needs these their monicker on eBay is imagebyroberts2 . I only paid about 50.00 and that included the special cuts they made. Very professional and easy to communicate with.

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