# Do incandescent bulbs degrade?



## Bullman (Jan 18, 2010)

I have a Streamlight Strion that I have used as a duty belt light for a couple of years now. I have noticed that the light was just getting dimmer, so I got a new battery, but it seems that the light isn't performing like it did when it was brand new. Now the light doesn't get used a lot, but it does get used. I normally rely on an Ultrastinger or a Malkoff modded Maglight for primary flashlight duties, but sometimes your away from the car and need a light, which is what the Strion is for. So my question is, since the light doesn't seem to be up to snuff with a new battery, could it be that the bulb is not 100 percent? 

Anyone have any ideas on how to get my Strion back into shape?


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## ampdude (Jan 18, 2010)

3.7V bulbs are just not very bright to begin with. Maybe you are just noticing that it is not as bright as the other lights out there, because most of the xenon lights out there are 6V or higher. But to answer your question, yes incan bulbs will degrade over time. But this is usually only apparent when they are overdriven or driven under spec so that the xenon/halogen cycle doesn't take place properly. Sometimes the bulb will blacken if this is the case. I've had many bulbs, especially Surefire lamps that have many hundreds of hours on them, with no noticeable degradation.

I had a bad experience with a Strion bulb darkening as well a couple of years ago when I tried FM's E-series Strion socket mod. It might be a problem with the Strion bulbs in general.


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## fivemega (Jan 18, 2010)

*Strion bulb is xenon (not halogen) and will degrade gradually and must be replaced even if filament is not burnet out.*


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## ampdude (Jan 18, 2010)

fivemega said:


> *Strion bulb is xenon (not halogen) and will degrade gradually and must be replaced even if filament is not burnet out.*




Thanks FM, I thought the Strion bulb was xenon-halogen, like the SF bulbs. I didn't know there were bulbs only made with pure xenon. My understanding is the stuff is pretty expensive and is used in small amounts in xenon-halogen bulbs (like SF) to prolong their lifespan.

I'd love to hear what mdocod, Outdoors Fanatic and Lux Luther have to say about this.


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## LuxLuthor (Jan 18, 2010)

I don't know anything about the Strion bulb in particular, but details could be looked up.

This is not as clear cut as you might imagine. First, the term "halogen" means "Salt former" and refers to a group of elements that inside of bulbs react with heated tungsten metal filament to recycle it and extend life. from the periodic table, and at room temperature halogens exist as:


*Solid**- Iodine, Astatine*
*Liquid- Bromine*
*Gas- Fluorine, Chlorine*
You can have a bulb filled with a Noble Gas which does not tend to react with other chemicals or metals (easily), namely:


*Helium*
*Neon*
*Argon*
*Krypton*
*Xenon*
*Radon*
Many bulbs use a combination of Halogen (typically Iodine) and Noble gasses (Krypton/Xenon). All of the various combinations of glass/quartz, filament composition, gas fill, pressure, quality control, etc. give different performance and longevity results. There was a thread about this topic a few years back. Post #2 has links that go to Don Klipstein's website with this page on Xenon, and this other page on Halogen.

I don't see why a well made and sealed Xenon bulb would allow that particular noble gas to leak out if unused, unless it was defective.


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## computernut (Jan 18, 2010)

I had an old minimag that the bulb was blackened. I replaced the bulb and it's brighter now but still not as bright as I remember it lovecpf


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## Bullman (Jan 18, 2010)

Wow, thanks for the wealth of information guys. I might try the spare bulb in the tailcap to see if it helps things.


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## Bullman (Jan 18, 2010)

The new bulb seems to have helped, the light is appears brighter now, thanks for the help again.


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## Linger (Jan 22, 2010)

minor point
If you've had the torch for a while, dirt and oxidation may be building up on the contacts. A little cleaning of all electrical contacts might help.


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