rough temperature limits on SF turbohead lexan lenses?

novice

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Apr 19, 2006
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1,033
I just recently acquired a Surefire 12zm, with the TRTH (threaded turbohead). From doing some searches here, there are allusions to the possibility of the lexan (polycarbonate) lens starting to deform if it gets too hot. I am wondering if anyone has an idea of what "too hot" is. I don't have the unobtainable original N62 bulb, but I think that someone mentioned only using that lamp with the TRTH for a total of 3 minutes constant-on before turning it off to let it cool down. I ordered a tad customs G4 halogen socket, and was thinking of two of the more possibly practical choices for a bulb to use with it. According to Lex Luthor's destructive incan bulb tests, the Osram 64250, when running at 7.4 volts of of 2xLi-Ion, should produce about 91 degrees Farenheit, and the Hikari JC 5607 should put out about 102 degrees at 7.4 volts. Should these temperatures be safe for extended use in the TRTH without overheating? Does anyone have an informed opinion of what the upper temperature limit with a large SF lexan lens would be? Thank you!
 

konifans

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Jan 1, 2015
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The Philips 7387 (10W) should work well and not as hot as the stock bulb.
 

novice

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Joined
Apr 19, 2006
Messages
1,033
Thank all of you for the info!

bykfixer,
I would be happy to replace the plastic lens with a glass one, if it were more doable (for me). The lens is a press-fit. Getting it out would be difficult (and I've seen one old thread that said that it would break it), and it seems that that type of mounting is much more suited to plastic, than glass. I don't know how the replacement glass lens would then attach. Thank you for the suggestion, though. I do have a KT-1 to use hot bulbs in. I was just hoping someone could give me a good idea of what would work in the TRTH, temperature-wise.
 
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