Not surprisingly, to melt glass in a modern fashion you need quite a few pieces of equipment in your workshop. Most can either be purchased at a hardware store, a welding supply store or a bead-making store. Here's a basic list:
- Torch (aka source of fire): The simplest one is the single-fuel torch, which gives off a cooler flame than other torches -- a good thing for beginners because it means the glass softens more slowly, giving you more time to work with it.
- Fuel tank: The fuel feeds the flame. Refillable and non-refillable tanks are available.
- Hose, clamp and brackets (or a stand): These allow you to attach the tank to your work table and attach the tank to your torch.
- Check valve and flashback arrestor: These are two pieces of safety equipment that make sure the flame from the torch never has a flashback, which occurs when the flame goes back in the hose toward the fuel tank, instead of out into the air. To prevent a flashback (and possible explosion), a check valve keeps gas flowing in the correct direction. A flashback arrestor also ensures gas is moving the right way and also has a component that extinguishes a possible flame -- two safety checks in one.
- Regulators: These help you control the flow of fuel to the torch.
And then there's the art of cooling and annealing the glass -- a very important step in lampworking. If you cool the glass too quickly, it will break due to thermal shock. When glass is heated, it expands. If the glass is heated or cooled too quickly, the different layers of the glass expand and contract at different rates, causing the glass to pull away from itself, and crack or break.
Bob Ponton, veteran glass blower and office worker for the American Scientific Glassblowers Society, explained thermal shock this way: Think about a heating a 1-inch (2.5-centimeter) ring of glass. Heat it too fast and the temperature of the outer quarter-inch (0.6 centimeters) will rise faster than the middle three-quarters, and that outer piece will expand and break away from the middle layer, cracking the glass.
He also explained that the glass used for lampworking is different than that used for, say, making soda bottles. "Put a pop bottle in the torch, it will look like it exploded because the glass expanded so quickly," he said. For lampworking glass, boron is added to the glass to change the expansion rate, or what's known scientifically as the coefficient of expansion.
Before he retired, Ponton made glass used for scientific purposes, and he used types of glass with maybe four or five different coefficients of expansion for that type of work. For the glass art he makes, Ponton said sticks with one type of glass, as do most glass artists. One thing that changes the coefficient of expansion is the chemicals added to give the glass color, so artists look for a glass that gives them a great color palette and then learn to work with the properties of that particular glass.
There are different tools to cool hot glass, including:
- Fiber blankets: Slip the beads between layers of the blankets to cool at a slow, safe rate.
- Vermiculite: The same stuff used to aerate soil can also be used to cool beads. First you heat it in a crock pot or in a regular pot on a hot plate, and then push the bead into it. About 45 minutes later, you move the bead to another pail of room-temperature vermiculite.
- Kiln: A kiln allows you to cool beads at controlled temperatures. It's also the most expensive piece of equipment associated with lampworking. Luckily it's not something a beginner necessarily needs to buy. If you make beads in a home studio, you can put a batch in a safe space and then borrow or rent time at the kiln of someone you know (such as a teacher) to anneal them.
Read on for the equipment needed for the all important steps that come between the heating and cooling of the beads.