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Redhead bulb exploded


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#1 Mark McCann

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Posted 20 April 2011 - 05:16 PM

Hi all,

I was testing some lighting scenarios out in my house tonigh, i was using a 1kw redhead light when after ten minutes of usage the bulb exploded. I know the grease on the fingers can make the bulb explode, but i didnt touch any glass elements with my bare hands so i cant figure out why the bulb would explode. It was in its case for a good while today before i brought it out to test outside at about 9pm, would the temperature change from its case to outside have had any effect? The bulb has been in use for a long time, i booked the light out from my film production course at any so its probab ly had alot of usage without being change, could it just have exploded because it was a very old bulb?


Any replies would be awesomeness.

Mark
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#2 Adrian Sierkowski

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Posted 20 April 2011 - 05:17 PM

Someone before you may have touched the bulb; and ot the bulb was probably banged around and just weakened. And, yes, older bulbs can pop sometimes. Hopefully no one was hurt.
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#3 Mark McCann

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Posted 20 April 2011 - 05:25 PM

Someone before you may have touched the bulb; and ot the bulb was probably banged around and just weakened. And, yes, older bulbs can pop sometimes. Hopefully no one was hurt.



Well we used it earlier in the day, shooting a scene for about two hours without a prob, so ill guessing it was an older bulb. Fortunately no one was hurt, it has a steel mesh over it so alot of the glass was kept inside, just want to check for any reasons it could explode incase i did something stupid that i dont want to do again with a light.

Thanks
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#4 Adrian Sierkowski

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Posted 20 April 2011 - 05:32 PM

Well, you're a student, so I'm sure you did something dumb with the light ;)

In seriousness, though, a blown bulb happens, it's when it happens as soon as you put a new bulb in that you need to worry about it.
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#5 Mark McCann

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Posted 20 April 2011 - 05:38 PM

Ah thats relieving news, i was already coming up with excuses to make to my media department when i returned it tomorrow.
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#6 Adrian Sierkowski

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Posted 20 April 2011 - 05:49 PM

Normally; at least when I was still getting equipment from the equipment office, they'd provide a spare bulb or two. Just tell them the truth; you powered it up and it ran for 10 minutes or so, and poof, blew. If anything, the bulbs proper are no more than $30 so [at most] if they want to charge you, which they shouldn't as bulbs are expendables, it won't break the bank.
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#7 John Sprung

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Posted 21 April 2011 - 12:23 AM

There are three ways that a bulb can explode:

1. Dirt, fingerprints, bugs, etc.: It traps heat on the surface, which melts the quartz. The color temp stays constant until it blows. This happens randomly, pretty much any time.

2. The filament breaks, and an arc forms between the ends: This builds up pressure inside the bulb until it pops. The color temp goes way up during the arcing. This is usually caused by an impact while the light is on, such as the stand falling over.

3. Thermal shock, such as water getting on the globe while it's on.

A typical burnout from old age doesn't break the envelope or alter the color temp, it just goes out like an ordinary household incandescent.



-- J.S.
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#8 Brian Drysdale

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Posted 21 April 2011 - 11:11 AM

Also, the reason to ensure you have a safety glass/mesh fitted on these lights. Exploding bulbs do happen, so best have the protection in place.
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