Will Heat-On crack my flask?

Heat-On has an advanced, proprietary design (shape) that means it does not have the same risk of shearing flasks as other companies’ blocks.

Heat-On’s proprietary design also means that flasks sit lower down in the block than other companies’ blocks, maximising the heated surface area, and meaning that if there ever was a break in the glass, the block can contain the contents, unlike competitor blocks.

If used correctly (see below), flasks should not break in Heat-On.  The few reports we have received of flask breakages have been due to one or more of the factors below.

Factors to consider:

• Use suitable size/shape flasks
• Ensure flasks are in good condition – not scratched, no hairline cracks or chips, and annealed during manufacture (purchased from a reputable supplier)
• Ensure the glassware and Heat-On are clean – no chemicals/residue/grit between the two
• Don’t pressurise flasks – don’t seal heated flasks closed (unless specifically designed for pressure)
• Don’t use very large/heavy equipment set-ups above the Heat-On
• Preferably load your glassware into the block when the block is at ambient (room temperature).  If this is not possible, at least ensure that flasks are removed at or above the temperature they were originally inserted – e.g. don’t heat up the Heat-On, then insert your flask, then allow the Heat-On to cool back down to below the temperature when the flask was added