Question: What is glass?
Answer: Glass consists of 60% sand, 30% potash and soda ash, and 10% lime. In 1608, sand was gathered from the beach, potash is wood ash, soda ash is seaweed ash, and lime is crushed oyster shells
Today we use natural gas to melt the sand mixture at almost 3000 degrees. In 1608, hard woods were used, and it took about two weeks to achieve a melt
Question: How do you stand the heat while working?
Answer: we drink lots of water, and look forward to winter.
Question: How hot is the furnace?
Answer: during the day when we work with the glass it is kept at 2080 deg. F. At night when we are melting the raw materials we cut it up to 2350 deg. F.
Question: Do you get burned a lot?
Answer: No. After a mistake or two, you become really aware of what you are doing.
Question: Where do you go to learn how to blow glass?
Answer: We offer an apprentice program here. Most of our glassblowers learn here in that apprenticeship. There are many universities in the US that offer glass within their art departments. Private studios often offer classes. Also there are several major craft schools offering glass, such as Penland, Pilchuck, and Corning.
Question: How long does it take to learn glassblowing?
Answer: Our apprenticeship is four years long. That is how long it takes someone to learn all of our pieces.
Question: What fuels your furnace?
Answer: Today we use a modern furnace, fueled by natural gas. In 1608 the furnace was fueled by hardwoods.
Question: How did they get the furnace so hot using wood?
Answer: We estimate that they would have to fuel the fire 24 hours a day for 7 – 14 days straight to build up enough heat in the furnace and maintain it long enough to melt a batch of glass. Their furnace would have been designed to create a strong natural air draft.
Question: How do you make different colors of glass?
Answer: You add small quantities of different metal oxides to the raw materials before melting them. Iron or nickel, in common sand, make the glass green. Other metals are added to create different colors. Cobalt oxide makes blue. Manganese oxide makes purple. Gold or cadmium and selenium make red.
Question: Why did they want to make glass at Jamestown in 1608?
Answer: They were trying to establish profitable industry. The demand for glass in England was increasing. All of the raw materials needed for glassmaking were present at Jamestown. There was an abundant supply of hardwood trees for fueling the furnaces.
The Glassblowing Process
1) Raw materials are mixed together in the proper ratio to form the batch. The main materials are sand, soda ash, pot ash and lime.
2) The batch is put in the furnace and melted to form molten liquid glass.
Our modern, natural gas furnace, melts batch in 9 hours at 2350 deg. F.
3) The tips of blowpipes and gathering irons are preheated in the fire
until they are slightly glowing.
4) Glass is gathered on the end of a blowpipe by dipping the tip of the
pipe into the pool of molten glass and turning the pipe.
5) The glass is rolled on a steal plate called a marver to center it and
slightly cool the exterior.
6) Air is blown through the pipe into the glass to expand it and make it
7) Hand tools, gravity, and more air are used to manipulate the shape.
The glass is taken back to the fire (a reheating chamber called a glory
hole) to re-soften it as many times as needed.
8) Once the basic shape is formed the piece is transferred to a solid
gathering iron called a punty. The punty has hot glass on the tip, which fuses to the bottom of the glass piece. The piece is broken off of the blowpipe.
9) Once the piece is again reheated, the final shaping is done to the part
previously attached to the blowpipe.
10) The finished piece is placed in an annealing oven. The oven slowly cools the piece for about 12 hours. This relieves the stress in the glass and prevents it from breaking.