In uk.d-i-y N. Thornton wrote:
Rob Morley wrote in message et...
In article , "N.
Thornton" says...

a crack will let air in, result: instant filament failure.
araldite hasnt got the remotest chance of surviving the temp.

It's not the envelope that's cracked.

AFAIK there isnt anything else on a 500w halogen bulb that could crack.

Apart from the ceramic endy bits that the OP specifically said had cracked.