How to Fire Armstrong's Fire 82

Getting Started

Here are a few things that you need to know before jumping into fusing with Float Fire 82™. If you have previously fused with other tested compatible fusing glass, you may be able to use a lot of what you already know. Float glass does have some slight differences. Float glass is the glass that you know as window glass, the same as the glass in the windows of your house. Float glass has a tin side and an air side. To achieve consistent results, it is necessary to determine the tin side of the clear float glass. To do this you will need a short wave UV light, sometimes called a tin detector or tin scope. The side of the float glass that produces a glow when the UV light is shone on the clear glass at a 45° angle is the tin side (see figure 1). The opposite side is the air side.

You may choose to fuse either side of the Float Fire 82 sheet glass to the clear float glass. A different appearance will result depending on the side that you use. When fusing with Float Fire 82 with the color side up, there may be small lines or separations between individual pieces of glass. When fusing with the color side down, the possibility of separation is reduced.

An exception to the recommendation above is the metallic colors (F600 and F611). These colors must be fused color side up and on the top layer due to the metallic qualities of the glass. If these colors are fused color side down or are fused under a piece of float glass, they will lose the metallic look and may discolor. Some of the frits and powders will react to the tin side of the float glass. We recommend that you apply them to the air side of the float glass. This will provide a more consistent result.

What is Devitrification?

Devitrification or “devit” creates a milky looking haze that occasionally occurs on the top surface of glass that has been heated in a kiln. Molecules in the glass crystallize and the glass may become opaque and brittle. Many fusers consider devit to be undesirable. One way to reduce the possibility of devitrification is to fuse your project with the tin side of the float glass up. You can do this is by assembling your project in the kiln. Put the Float Fire 82 sheet glass on bottom and then cover it with the clear glass. The tin side of float glass is less likely to devitrify in the kiln and will create a clear finish. If you must fuse with the tin side down, simply use a devitrification spray such as Spray A or Super Spray. Most, if not all, devitrification sprays contain chemicals that may be harmful if used in projects that will be used for food. Another way to eliminate devitrification is to completely cover the air side of the float glass by sifting frit, powder, confetti, etc. over the entire surface of the float glass (see figure 2). The frits and powders are very resistant to devitrification and will prevent the clear glass from devitrifying.

Getting Rid of the Bubbles

Air bubbles can be a real nuisance when you want your finished piece to have a neat, clear appearance. The easiest way to get rid of the bubbles is to fuse with the color or design elements on top (see figure 3). If you try to fuse with your design in between two layers, you will almost always get bubbles. Another way to reduce the bubbles is to incorporate a “bubble squeeze” into your firing schedule. Float glass begins to soften around 1200º F, so your bubble squeeze should be done between 1100º F and 1250º F. During this temperature range you should gradually increase the temperature allowing the air to escape prior to the edges sealing. The firing schedule that we have provided incorporates a bubble squeeze.

A Little Bit About the Float Fire 82 Lineup

Float Fire 82™ Glass

  • Available in 43 colors
  • 2mm thick
  • Standard sizing
    • Full sheet: Approximately 27.5 x 31.5” or 6 square feet
    • Half sheet: Approximately 27.5 x 15.75” or 3 square feet
    • Quarter sheet: Approximately 13.75 x 5.75” or 1.5 square feet
    • 1 square foot: approximately 13.75 x 10.5”

Float Fire 82™ Frit

  • Available in 33 colors
  • Each color is available as
    • Powder (W)
    • Bubble Powder (P)
    • Fine grain frit (2)
    • Medium grain frit (3)
    • Coarse grain frit(4)
    • Extra Coarse grain frit (5)
    • Confetti
    • Eggshells (larger, wafer thin pieces of confetti)
    • Glass Paints
    • Stringers
  • Standard sizes
    • Jars - Frit
      • 250 grams (approximately 8.5 ounces)
      • 1kg (approximately 2.2 pounds)
    • Tubes - Stringers
      • Approximately 24" long
      • 250 grams per tube 

The latest addition to the Float Fire 82 line is Bubble Powder. It is perfect for anyone that wants to make their own seedy glass. Bubble Powder is easy to use. All you have to do is sift or pour the bubble powder on top of a piece of float glass where bubbles are desired. When your design is complete, cap (sandwich) your project with another piece of float glass. Now place it in the kiln and fire it to a full fuse. The size and quantity of the bubbles can be varied by modifying the fusing temperature, soak time, the quantity or thickness of the powder and by using different thicknesses for the top layer of glass. The colors that contain lead will produce smaller, more frequent bubbles than the colors that are lead free. 

Float Fire 82 Glass Paints are available as a dry powder in ASTM mesh 230. They can be used for traditional brush painting or air brushing. Recommended firing temperature for Float Fire 82 Glass Paints is 1450-1475º F for approximately 20 minutes. When using Float Fire 82 Glass Paints, the type of painting you do will determine the best medium with which to dilute the paint. When painting with a brush, traditional mediums like clove oil, or lavender oil may be used and the paint can be thinned with Canada Balm. When air brushing, gum Arabic dissolved in warm water and thinned with mineral spirits is recommended.

Float Fire 82 Samples and Starter kits

  • Float Fire 82 glass sample set – 43 colors, sample size is approximately 3” x 3”.
  • Float Fire 82 frit sampler – a small amount of each color which also represents
  • all of the available sizes
  • Float Fire Frit pre-fired color board – a 14” x 19” inch float glass sheet that
  • represents all of the available colors in the frit line, fired as powder. One sample
  • of the additional frit sizes, confetti, eggshells and stringers has also been fired to
  • illustrate the size of each.
  • Float Fire 82 Starter set – this set contains approximately 10 pounds of
  • randomly selected Float Fire 82 glass, a UV light used to determine the tin side of
  • float glass, and the Frit Sampler.

Firing Schedules

The following schedules are only guidelines and may need some slight revisions based on the type of kiln that you are using, ambient temperature, the elevation of the area in which you live, and the thickness for the glass that you are fusing. These schedules are suitable for glass up to 3/8 inch thick. The bubble squeeze is between 1100 ºF and 1245ºF. Annealing occurs between 1100 ºF and 900 ºF. After the kiln reaches 900 ºF, you can turn the kiln off and let it cool to room temperature.

Full Fuse

Degrees per Hour Temperature (°F) Hold
250 1100 15
200 1245 30
9999 1510 15
9999 1100 35
150 900 0

Frit Casting

Degrees per Hour Temperature (°F) Hold
400 1100 10
250 1245 30
300 1540 20
9999 1015 120
80 800 0


Slumping/Drop Molds

Degrees per Hour Temperature (°F) Hold
300 1200 30*
9999 1015 35

  *Or until complete