Dean's Glass Torch Working Sudio

I took a torch working class a few months ago. I wanted to be able to make marbles for my stained glass kaleidoscope. I had a blast. The visceral feeling of manipulating molten glass is amazing. Even poorly made glass pieces are beautiful. I kept going back to Sundance to rent studio time. In no time, I was able to make reasonable marbles. Eventually, I decided to install a glass studio in my garage.

Ventilation

Torch working glass requires extensive ventilation. The materials in some colored glass rods produce harmful gases when heated. And a burning torch produces C0₂, which can be dangerous if allowed to collect for an extended period.

The online guides say you need to be able to replace the air in the room every couple of minutes. My garage is 4000 cubic feet. Most bathroom fans move about 80 cubic feet per minute (CFM) -- meaning I'd need 25 fans! I pictured myself with my hair standing straight up due to the force of the wind.

A better solution is to build a small enclosure (hood); this significantly reduces the volume of air that needs to be turned over. Here's a few photos:

Ventilation hood	Ventilation hood (inside view)
Ventilation hood (with side panels)	Fantec inline fan

The next problem was where to vent the air. Most people punch a hole in the wall, or roof. I live in a townhouse. The kitchen is directly above the garage. Left, and right are my neighbors. Out the garage door seemed to be the only choice. I ran a six-inch duct from the hood to the garage door. I didn't want the gases coming back on me, so I crack the garage door open a foot, and install a board with a cutout for the duct.

Ventilation Duct

Ventilation Duct (tail end)

Ventilation Duct (out the garage door)

Table

Tables are easy. A sheet of pressboard, some 2x2s, and 4x4s and I was done.





Table

Oxygen and Propane

I bought a 155 cubic foot oxygen cylinder at a nearby welding supply store. This is the largest size I can easily handle. It's 90 lbs, and fits in my trunk. Should be enough for about 30 hours of torch time. Propane is available everywhere. I got my tank at Homedepot. The regulators are all single-stage, made by National.

Oxygen cylinder

Oxygen regulator

Propane tank

Propane regulator

Work Surface

Molten glass is hot. The ideal work surface is fireproof, and clean. Wood is neither. Some people use granite, or tile. I chose the most common type: stainless steel. I got mine custom made with a rod rest along the back edge.








Stainless steel work surface

Torch

The most important tool is the torch. I got a National 8M mostly due to its versatility. This torch supports about a 20 different tips. It can operate as either a premix, or a surface mix torch. Premix torches blend the propane and oxygen internally; as a result they burn hotter and work well with hard glass (borosilicate, Pyrex). Surface mix torches are cooler, and are used with soft glass (Moretti).





National 8M torch

Kiln

Torch working typically involves bending and twisting a piece of glass which is soft, but not liquid. As a result, internal stress builds up within the piece. If not relieved, the glass will shatter as it cools. I've had marbles explode as if hit by a hammer.

For this reason, almost all pieces are annealed. The glass is heated in a kiln to about 1000^o, and soaked for an hour or two. This is hot enough to relieve the stress, but cool enough to prevent distortion. Afterwards, the piece is very slowly cooled.

The model I bought has a digital control. You set the temperature, time, and rate of change, and then go watch TV.

Kiln	Kiln (inside view)

Safety Glasses

Torch glass artists wear safety glasses for three reasons:

1. Physical protection. Heated glass can shatter, producing flying fragments.
2. Sodium flare. Heating glass in a torch produces a bright yellow light. While not hazardous per se, it severely obscures vision. Most glass working glasses block this narrow band of light
3. Infrared. Over several year the infrared light produced by a torch can cause photosensitivity, and even cataract.

Torch workers traditionally wear glasses with didymium lenses. These block the sodium flare, but only partially block infrared. The exact amount of infrared protection necessary is open to debate. Working hard glass, which requires a hotter torch, is worse than soft glass. Fuming, and certain color rods produces more infrared. Larger projects are worse since they require a bigger flame. There is also a variance in individual tolerances (apparently some folks ancestors lived in brighter environments).

But I don't want to go blind, I've decided to error on the side of safety. The online stuff I've read says Boroscopes (made by Phillips), and Auralens' AGW-286 work well. I plan to get a clip-on set of Boroscopes, since I wear prescription glasses.

Torch Working Tools

Torch working artists also have many tools to manipulate molten glass. I got a pair of squashing pliers, needle nose pliers, graphite pad, scissors, marble mold, and a probe.





Miscellaneous Tools

Conclusion

This project took a lot longer than expected. I went through several failed iterations of the ventilation system. I looked at dozens of fans, before I found one with enough air flow. And I spent hours online reading up on kilns, torches, and oxygen cylinders. But the journey is half of the fun. And what else is a retired engineer gonna do with his spare time? In the end I had a very nice glass torch working workspace.

Dean

Dean

Acknowledgements

Much thanks to John, and Dottie at Sundance for helping me select equipment, and general tips on glass torch working.