28 July 2009

Changes to Bullseye Glass Anneal Temperature

Goodbye 960
Unless you’re living under a rock you already know that fused glass manufacturer, Bullseye, quietly announced that it is changing its standard annealing tables. The recommended anneal soak temperature drops to 900F from 960F.

According to Ted Sawyer, who runs BE’s research and education department, the closer you get to the strain point of soda-lime glass, the less time you need to spend in anneal soak. Stress in the glass relaxes more quickly at 900 than it does at 960.

Shorter anneals are advantageous for folk who make a living with glass art, since it means they spend less time in production with every piece. It could shave 200 hours off the schedule for an 8-inch thick kilncast piece. And if the glass is cooling over a shorter temperature range, the risk of breaking may be less.

Bullseye also emphasized (strongly) that there’s nothing wrong with the old schedules. They can still be used.

BE does not have all their new tables online, but here is their thick annealing schedule: Bullseye_annealing_thick_slabs

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