Calculating firing time

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I am a world-class Microsoft Excel junkie (My motto should be Pivot Tables R Us), so you gotta know that if there is a way to get glass into a spreadsheet, I’m gonna find it.

I got tired of “figgerin” on paper when my stuff would come out of the kiln. So I built a little firing calculator to do it for me, and you’re welcome to download the file and try it. (You’ll need an application that can read Microsoft Excel 2003 files). At some point–if I EVER get around to relaunching my main website–I’ll probably convert this to a web calculator so I can get to it from wherever.

Kiln time gets pretty critical for casting, since there’s stuff you need to do at various stages of firing, such as closing vents when the molds have dried out. Figuring out ahead of time when stuff like that will happen lets you build a more convenient schedule…unless you just like getting up at 3am to close the kiln door.

Obviously it’s less useful if you’re just turning on the kiln and letting it run by itself, which is probably 95 percent of fusing projects. But it’s still nice to know when the work will be finished, and a printout of this thing gives you an easy-to-read schedule to input into your controller. It’s also useful for understanding how well your kiln adheres to the schedule, particularly on the downramp. My old Skutt, for example, was usually 3-4 hours late, primarily because of slow cooling.

Anyway, enjoy–let me know if you find problems with it. I’ve got a bunch more stuff in my version of this, manufacturer’s annealing tables, thickness calculators, etc., and that’s something you might want to add for your particular glass(es). At some point I’ll dig out MSdev tools and make it truly webbed, but for now I like the quick-and-dirty. Enjoy.



  1. cynthia August 14, 2008 at 11:25 am - Reply

    Yes, I looked at that and I like it. When I’m working with casting, though, it’s also useful to have a date, because the firing can take a couple of weeks. That’s why I went ahead and built my own. But I use Paul’s glass calculator all the time–this is an extremely useful site!

  2. chaniarts August 14, 2008 at 11:16 am - Reply

    see for another one

Comments welcome! (thanks)

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