How to Slump a Deep Bowl

3447627248_e98d5f0c3eI’m working on a project that has been a bit of a challenge and I’m getting ready to start another approach. I’m making glass for a wall sconce and had been draping the glass over to “wedges” that together formed a dome. Each half of the dome represents one of the pieces of glass for the sconce. A bit of a challenge is an understatement. Most of the time the finished dome was cracked and I did everything I could to make it work. Now I’ve made a mold of the two wedges and have a deep bowl to slump into. I’ve been told this is to be done in stages, a little at a time. Over at Creative Ceramics they have a pdf of how to do it so I thought I’d share it with all of you. Let’s hope for the best…


  1. says

    Bullseye has some online articles with tips on slumping with firing and annealing cycles. I am thinking that the piece might need a firing schedule modification. As also noted you might want to work in two stages stretching the glass gradually. The goal is to get the glass to stretch slowly and evenly. They advise a 300 degree an hour climb. For larger items that are deep you could go 250 an hour.

    Make sure you know exactly what type of glass you are using and following the proper annealing range. Better to anneal too long that not enough. I also have the polariscope film and use it to study fired objects. This tells you right away the condition of your glass after firing.
    Happy Firings!


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