A long, continuous oven used in glass manufacturing and studio glassblowing to cool hot glass slowly and evenly. By gradually lowering the temperature over several hours or days, the lehr relieves internal thermal stresses in the glass, preventing it from cracking or shattering at room temperature. Industrial versions often feature a conveyor belt that moves the glass through decreasing temperature zones.
Heard on the job
Load those finished bowls into the lehr immediately before they get too cold and crack on the punty.
Insider tip
Forgetting to turn on the lehr before starting a glassblowing session is a classic rookie mistake that results in a day's work ending up in the cullet bin.
Also heard as
- annealer
- annealing oven