Emptying the Pot

Annually we must do maintenance on our electrical glass furnace. Maintenance includes checking the elements, the electrical connections, and the crucible. If the electrical needs work or the crucible is damaged, you must cut the power off to the furnace. Before that happens, the crucible or pot must be empty. When it is full, our pot holds 300 pounds of molten glass. You must get the glass out while it is still hot by using it all up, creating art, or ladling it out. This sounds like a relatively straightforward process. So we had a bevy of folks here this morning to help out.

The Unexpected

We had made a ladle, which worked great as we removed globs of molten glass onto the steel marver. That’s when we made our first two aha’s – we could have blown a little more, AND we could have planned on doing some castings at this point. But, once the ladle became ineffective, we made a glass rake that picked up more and more glass by gently scraping the sides and bottom of the pot. After making a few of these (they get too big to be manageable, and you have to make them smaller while managing the heat), we had another aha moment! We did not have a pipe or rod long enough to reach the bottom of the crucible due to its height and the angle of the gathering port. So being fabricators, we made a steel rod with two bends — one to pass the gathering point and another to angle it into the pot’s base. Then we could pick up a “dollop” of glass at a time. All of this occurred at working temperature (2150 deg), so whenever you open the furnace door, it’s like you have opened the gates to hell. That was okay until the darn kevlar mitts started catching fire because it is taking SOOO long to gather up that dollop of glass. Aha moment – higher temp liquifies the glass allowing it to pool in the bottom of the pot, while cooler temp allows for bigger gathers!

Problems

Then we start having problems with our furnace controller. The temperature begins to lower a couple of degrees a minute. It’s 3:30 pm on a Friday, and we are calling the controller vendor trying to get technical support. We need to stop this relatively rapid temperature decline quickly. We reach out to our glassblowing friends for their expert advice. Luckily, they promptly responded. We reprogrammed the controller and emptied our pot for the first time. The furnace is slowly cooling now! Working glass is intoxicating and exciting. And sometimes a little stressful when you are doing things for the first time. It is an exciting adventure we are on, with lots of opportunities for AHA moments and creativity.