Tuesday July 25, 2023 | by UrbanGlass Staff

Hot Popping & Glass Painting with Bloomberg Arts Interns By Alyx Scala, 2023 BAI Intern

This July, UrbanGlass hosted 40 interns from Studio Institute’s Bloomberg Arts Internship program for a hands-on workshop focused on up-cycling glass bottles. Bloomberg Arts Internship (BAI) is a beneficial paid summer program for juniors in high schools across NYC. In this program, accepted students are given help preparing for college through college writing classes and a chance to try new things through various worksites. Students could be placed in any of the participating sites that work with the arts. UrbanGlass is one of these sites where teens are able to explore art through an entirely different medium they probably never thought to use before, glass! The entire intern cohort participated in this event. Once inside the studio, they were given a tour of the space, including the different shops and techniques that are possible. With safety glasses on, everyone got to see some professional artists at work. Eventually the cohort made their way into the cold shop, which is a space used for shaping glass at room temperature and without using heat.

When asked if anybody there had worked with glass before, nobody said yes. This was a new experience for everyone. In the weeks prior, UrbanGlass had collected a good amount of glass bottles to be used for this event. After scraping labels off and rubbing away the glue, these recycled bottles would be turned into something beautiful by the students. Everyone was excited to learn the technique of hot popping, which is where thermal shock is used to essentially “cut” straight through glass. Once that top half piece where the opening to the bottle is cut off, you are left with a cup. Depending on the bottle you used, these can now be repurposed into multiple cool things; such as drinking glasses, decorative pieces, planters, containers to hold things like pencils or whatever someone's creative mind can make out of it. Who thought that glass yogurt container or that Coke bottle could be turned into something totally different? Something you can use everyday instead of another bottle to be thrown away. Some creative choices didn’t even involve hot popping. Instead, some students chose to keep the top half, perhaps to be used as a vase. 

The materials we used for hot popping were our bottles of course, a glass cutter, a brulee torch, diamond pads, and a banding wheel. The banding wheel is a flat disc-like tool that spins. First you scratch a ¼ inch mark into the glass bottle, wherever you want it to be cut across. Then you center your bottle on the banding wheel. Turn your torch on and point the flame directly at the mark you made, but don’t let the torch sit in that spot too long. Start spinning the wheel at a medium pace, while holding your torch still. If you move your torch around, the cut will not be very clean across. You don’t want to hold your torch on the bottle for too long without spinning it because then the heat is not being spread evenly around the bottle. What is happening is the heat you’re putting on this specific part of the bottle creates thermal shock that causes the glass to crack at the score mark, which then runs all the way around the bottle. If there is too much heat on one part, a result of not spinning it while torching or letting your torch sit on a still bottle for too long, the glass will not cut evenly and  may crack in an unwanted spot. The mark you made on the glass is essentially manipulating the glass and telling it where to cut once you apply heat. If done correctly, the top part of the mark you made will simply ‘pop’ off. The torched glass gets hot so we were very careful when removing the top and placing it to the side. We are left with a cup-like shape of glass! Once the glass cools we wet our diamond pads, which is a file made of crushed up diamonds used for sanding, and we file the rim of our cup. It’s very important to wet the diamond pad before filing for two reasons. Firstly, when sanding the sharp edges down there will be a lot of dust you don’t want to breathe in, if the pad is wet then the dust doesn’t become airborne. The water is also to keep things cool, when you are sanding there is a lot of friction that might make the glass hot to where it could crack. Students asked “Why do we file on an angle and not across the top”? The purpose of sanding is just to dull the sharp edges, not to make an even cut. 

Some people chose to try hot popping, some chose to watch, but either way everyone had a fun time. Once your cup is cool, and sanded, it is ready to paint! The painted designs will be fused permanently onto the glass in a kiln (oven). The kiln will fire for 45 minutes at 350 degrees Fahrenheit. The different style choices were so unique and creative! Some of the interns chose to do a pattern, some chose a more loose design with no pattern. There were illustrations of memes and animals and doodles. One glass had a cherry pattern, while another was a meme of Bugs Bunny! Flowers were a common theme among stylistic choices. Everyone showed great interest in expressing themselves through glass, even though nobody had done this before. They were all excited to paint their own little project to take home. This hot popping and glass painting event was a success! It’s exciting to try new things, and now the students of Bloomberg Arts can say they’ve worked with glass and have a little memory on their shelf to prove it.