How to Make a Bluebird  
  Some people ask us where we get our beautiful blue glass. The answer is we make it. We actually mix our own glass recipes, from raw materials, when we make the Bluebird blue and cobalt glass. The raw glass mix, called a batch, is composed of about 63% pure silica (sand), 23 % soda ash, 1% dolomite (limestone), and 5 other minor ingredients.
Adding small amounts of metal oxides to the batch creates the colors in the glass. Bluebird blue contains copper oxide and cobalt contains cobalt oxide. Some of the other colors we use, such as red and green are actually made out of recycled glass. Red glass is created with selenium and cadmium. Green glass is made with a combination of iron and copper or just chromium.

Top Right: Copper Oxide, Top Left: Cobalt Oxide, Bottom: Silica
After the batch is mixed, it is shoveled into the furnace. The Bluebird glass batch is melted in a continuous feed, two-chambered furnace, which is heated with natural gas. The rear chamber, where the batch is melted, is kept at 2200 – 2300 degrees Fahrenheit.
 
       
 
Batch, including recycled bluebirds  
     
  The front, or working chamber, is usually kept at 1800 – 1900 degrees Fahrenheit. The heat from the furnace can be quite intense, especially in the summer. A smaller, moveable furnace is often used for melting other colors. This furnace contains a crucible, which holds the glass. Recycled glass is shoveled into the crucible through the front of the furnace.    
Once the glass has melted to the right temperature, one of our glass artists will open the furnace and gather a small amount of glass on the end of a punty rod. The rod must be continually rotated back and forth, at the work station, or the hot glass will fall off of the rod.
         
The glass artist uses a graphite or wooden tool called a block, or a pad of wet newspaper, to keep the glass centered on the rod. Keeping the glass centered on the rod is crucial. If the glass is not centered, it is very difficult to make a Bluebird. Blocking also cools the glass down somewhat.    
         
The glass artist then uses tools, such as jacks and pinchers, to pull out and shape the bluebird.
From Left: Block, Baby Pincher, Adult Pincher, Diamond Shears, Jacks        
 
Duane with Jacks
Duane with pinchers
Bird on punty rod
When the bird is completed, it is broken off the punty rod and attached to a glass base while it is still hot.      
   
 
 
When the entire piece is finished, it is placed in a lehr, which is a glass oven. The lehr is set at 900 degrees Fahrenheit and is gradually cooled over 12 hours. Hot glass artwork must be cooled gradually or it will shatter. After 12 hours the bluebirds are removed from the lehr and taken to the workshop where they are signed and dated and eventually placed in the showroom.
 
 

Back to Bluebird House

Back to Terra