CRACKS ON PANE OF GLASS

[llamekuf]

I have a glass door with steel frames surrounding the glass.
There are two sheets of glass, one of which seems to be toughened.
Unfortunately the toughened glass has developed deep cracks because I unwisely left a halogen heater on near the door.
I there any substance I can use to repair the cracks rather than replace the whole frame.
I would estimate that the door is about 30 years old.

[AlBags]

The cracks will not be in toughened glass .. It will only shatter like a car windscreen.
Probably Laminated. You can only stop-drill if standard glass. Use a sharp bit in an oil bath made with plasticene to cut just at end of crack, and just into laminate layer. You may make worse tho, if not very careful.
Failing this, strip the door and replace with a properly toughened panel or solid glass. This will be kitemarked when toughened. You should check original panel thickness to determine what you need. You can order toughened in standard glass or Solaglass.

[llamekuf]

Thanks for your helpful suggestions Albags.