Just how hot is it?

[flashlightlens]

Has anyone here ever come up with some numbers as to how hot the lens/lamp assemby gets on a high performance flashlight? I've searched through the forum and haven't been able to find anything.

 

[Rifter]

Hot enough to melt a Lexan lense and Nylon

If you find the melting point of lexan and nylon that would give you a ball park figure.

 

[lemlux]

Carley talks about their halogen bulbs reaching 300 degrees C.

Mag says that their lexan lenses are most prone to melting on wide flood setting. I don't understand the physics, but the reflective path of IR energy must be shorter further from the center of the lens. I would have thought that concentrated energy in the center of the lens would create problems.

I can tell you that a P91 LA run on NiMH's for 45 minutes in a DB6AA or DB8AA flashlight won't melt the lens so long as the Bezel is left loose enough not to allow the reflector to contact the lens.

 

[flashlightlens]

Rifter & lemlux - Thanks for the info. I'm trying to determine how to go about testing and comparing float & borosilicate glass. I want to see just how much thermal shock a piece of float glass can withstand and how it would apply to a flashlight application.