Is My MN15 still safe to be used? [heavy pics]

[Illum]

Cleaning out my closet today...erm..my fishing box today
I found my MN15 lamp tucked in along with the MN20 in a small bubble bag. I decide to take it out for close inspection and I noticed some residual discoloration around the base of the envelope, the colors similar to that of...well uh, heres the pics. you can decide what it looks like yourself:huh:

the family, [MN21s currently in the M6]


the MN15 in question [lateral]


MN20 [lateral] for comparison


the MN15 in question [frontal]


MN20 [frontal] for comparison


the MN20 has seen around 0.5-1 hour runtime momentarily, not continuously through one and a half set of cr123as
the MN15 (being js's X-LOLA idea) been through at least one set of cr123as. thats around 3 hours momentarily, not continuously

so fellas, whats the verdict on this one?:huh:

 

[WildChild]

Tungsten deposit?

 

[Mr Happy]

Are they halogen bulbs? I believe halogen bulbs do not like to be run momentarily. They need to run long enough to reach full operating temperature or the halogen cycle will not do its job and the filament can erode prematurely.

Blackening on the inside of the bulb envelope is usually a sign of filament evaporation. It is an indication that the bulb has used up some of its operating life.

 

[Illum]

I'd hope so...
it resembles the yellowish substance in this thread
http://www.candlepowerforums.com/vb/showthread.php?t=133305

I don't have any other used lamps I have that shows this phenomenon thats been through use.

If it was tungsten deposits....then why is it on the base of the lamp and not throughout?

EDIT: Didn't see your post Mr. Happy, forgot the halogen part
Surefire does state they use a propriety mix of Halogen in their lamps, I'm not sure about the MN15 but likely

 

[WildChild]

I'd hope so...
it resembles the yellowish substance in this thread
http://www.candlepowerforums.com/vb/showthread.php?t=133305

I don't have any other used lamps I have that shows this phenomenon thats been through use.

If it was tungsten deposits....then why is it on the base of the lamp and not throughout?

EDIT: Didn't see your post Mr. Happy, forgot the halogen part
Surefire does state they use a propriety mix of Halogen in their lamps, I'm not sure about the MN15 but likely

SF said they use some halogen mix that won't stop tungsten deposit, but will slow it down. Maybe the blackening at the base is caused by convection current inside the bulb that stopped the deposit around the filament, but only let it happen at the base?

 

[jayflash]

I'd vote, yes, that your lamp is OK to use.

 

[Illum]

:thanks:
thats all I need to know, I'll use it tonight and post if it turns blue