Wissmach Luminescent Glass
Luminescent glass is different than iridescent glass. It is low-fire—not high-fire like iridescent—and is intended for reverse fusing.
What is reverse fusing? Reverse fusing means placing your piece facedown on the kiln shelf and building backwards, fire-coated side down. If you are firing on a textured mold, place a piece of ThinFire between your boron-treated mold and the glass. If you fire your piece with the coated side up or cover it with another piece of glass, you will lose the coating. If you are slumping and do not go over 1,200 degrees, you can place the luminescent side up and not lose the coating. Luminescent glass is food-safe and has been tested by the U.S. Food and Drug Administration. However, please note that once the piece has been fired in your kiln, it is no longer a Wissmach product; it is your product. If you have been firing glass that could leave lead or cadmium traces in your kiln, that could get on the product, which would render it unsafe for serving food or beverages.
LEFT: Luminescent glass fired with ThinFire in between, with the coating facedown.
RIGHT: Luminescent glass fired facedown, directly on the mold.
Firing Schedules: Courtesy of Petra Kaiser and Wissmach Glass
Standard Fusing Schedule – 2 Layers Thick
Segment 1: 600°F/hr up to 1,000°F, hold for 10 minutes
Segment 2: Full/9,999 up to 1,410°F, hold for 10 minutes
Segment 3: Full/9,999 down to 950°F, hold for 60 minutes
Segment 4: 100°F down to 700°F, hold for 1 minute
Tack Fuse, Polishing and/or Slumping into a Mold
Segment 1: 300°F/hr up to 1,000°F, hold for 10 minutes
Segment 2: Full/9,999 up to 1,300°F or 1,350°F (depending on your desired results), hold for 10 minutes
Segment 3: Full/9,999 down to 950°F, hold for 60 minutes
Segment 4: 100°F down to 700°F, hold for 1 minute
Draping over a Mold and/or Polishing
Segment 1: 300°F/hr up to 1,000°F, hold for 10 minutes Segment 2: Full/9,999 up to 1,200°F or 1,220°F (depending on your desired results), hold for 10 minutes Segment 3: Full/9,999 down to 950°F, hold for 60 minutes Segment 4: 100°F down to 700°F, hold for 1 minuteNOTE: Not all kilns are alike. Your kiln size, controller type and individual project may require some alteration to the schedule for best results.