Melting of glass bulbs possible?

AtomSphere

Enlightened
Joined
Aug 14, 2004
Messages
710
Location
Edmonton, Canada
hi guys i think i juz had this problem with my p91...

its like this... i used the p91 on my surefire c3 bout 10minutes then let it rest some time(bout 5min) then i took out the bulb. and place it upside down on my shelf(its on the shelve most of the time
2-3 days later, when i pop my p91 in, there was no light! pop in p90 and its ok... I knowtise slight bending at the tip. isit unusual? BTW using 150s pilas
 

Lynx_Arc

Flashaholic
Joined
Oct 1, 2004
Messages
11,212
Location
Tulsa,OK
It is possible to melt glass.... but it could possibly be the tip was already bent slightly as bulbs with tips are made that way at times. To melt the glass likely you would have to overdrive the bulb for a long time at a much higher rate than the filament can handle.
 

Ratso

Enlightened
Joined
Jul 15, 2002
Messages
413
Location
Knoxville, TN
Glass melts at temperatures upwards of 1000° F (~550° C), so I don't think it'd be possible. Some Surefire bulbs do have slight bends at the tip, which do not affect performance.
 

Ginseng

Flashlight Enthusiast
Joined
Feb 27, 2003
Messages
3,734
That pigtail you see is indicative of a "top fill" type of bulb. The capsule is filled with inert gas and then the top is pinched closed. Some bulbs with ronded tips are called "bottom fill" because this is done at the base and you can't see it. Well, except in an unpotted Welch Allyn bulb, for example.

I have measured glass temperatures of upwards of 600F and have had no problems. But then better bulbs are built with borosilicate or aluminosilicate high temp, high chem resistance glass.

Wilkey
 
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