Glass Firing Schedules

Why Bother?

We all know that it’s true, so let’s just put it out there:   You don’t want to be here reading a tutorial  about firing schedules when there are so many more interesting topics on the other pages of this website.  So, before I lose you to pressed glass, faux stone, or photos cats with silly captions, consider these two simple facts:

  • As a full-time kilnformed glass instructor I see a lot of fusing “failures” and, by a very wide margin, most are the result of a the artist using an incorrect firing schedule.
  • Many of the firing schedules being shared online, churned out by software, and even taught in some classrooms are marginally useable.  More than a few are downright terrible.

When you consider the cost (in both time and money) of losing your work to a bad firing, it is easy to become frustrated.

Here’s the good news:  Understanding firing schedules and recognizing a bad one requires no math skills.   All it takes is a little information and some common sense.

This tutorial provides the information.

It may also help to put you at ease to know that almost nobody creates firing schedules from scratch.  I certainly don’t and I sometimes fire hundreds of different glass projects every single week.   Engineers who understand advanced mathematics, thermal dynamics, and phrases like “tensile at the mid-plane” and “parabolic variation” create firing schedules.

Our job is much simpler:  
1.    Recognize a good firing schedule.
2.    Adapt it to the project at hand.  

This Tutorial will help you to do both.

firing schedule tutorial

As with other pieces of your that i've read, I am so impressed by your sensible approach to aspects of fusing that can be frustrating.  Your explinations gave enough information to be very useful without feeling like an avalanche just rumbled through.  I have been fusing for a number of years now but the tutorial helped me refocus on some of the basics and that is always time well spent.  I'm looking forward to recieving my cold working book!

Thank you for your insights.

Michelle Caron

Caron Art Glass

Kaneohe, Hawaii

firing schedules

Using my recently purchased kiln, I've been firing with the preset firing schedules. At first they worked ok but then I started to have problems with strange slumps and some cracking after a few days out of the kiln. Thanks for these firing schedules - I know I need to adjust schedules for better results.

slumping schedules

I full fused a 9 1/4 " square made up of clear base and several different colored glass pieces, pebbles and some squares on top - 2 layers. Full fuse was good. When I went to slump this into a bowl shape it became a 5 1/4" square about 1/2" thick!  Shape was okay, it still looked good but was not what I was expecting. How did this shrinkage happen?

firing schedule changes

Hi, My kiln rampmaster is off by at least 50 degrees on the fuse schedule. So if I add 50 degrees to the high temp to make it fuse my glass properly...do I add 50 to all of the other ramps marks? Will it anneal at the right place if I don't? What do you think? thanks, donna

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