exploding fresnels

Pie4Weebl

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During a tech run last night for Peter Pan I had the lamp of 2k Fresnel explode on me. Luckily the gel burned itself out before hitting the set and I thank God that it happened on the 2nd electric so we could fly it in and remove it and not the 1st electric which is deadhung right by the teaser because of the flying rig.
 

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if you had the lense in there shouldnt of been an issue.... how did something hit the set?
 

Pie4Weebl

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on the colortran fresnels we have there are air vents around the side of the lense, we think the glass went through there.
 

soundlight

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Hmmm...sounds like someone touched the lamp before putting it in to the fixture.
 

nez

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yea that is one thing i try to always do my self is replace those so the lamps dont get touched
 

Pie4Weebl

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soundlight said:
Hmmm...sounds like someone touched the lamp before putting it in to the fixture.
I would be think that but that fixture has been frequently used for about 3 years now. (many a 16 hour day at full during dance competions) So I doubt it was that, right now we think the seal might have gotten damaged when the fixture got banged around when the flying was being set up.
 

moojoe

Active Member
what type of lamp? if i remember correctly, no fresnel has that long life of a lamp. say its on for 50 days a year at 16 hours, thats 800 hours. that alone is probably the life span of the lamp.
so someone must have changed out the lamp recently, touched it in the process, and it blew during your show. thats really the only thing that does that which isnt insanely rare.
 

Chris15

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nez said:
yea that is one thing i try to always do my self is replace those so the lamps dont get touched

My advice is to get some isopropyl alcohol. Definitely try to insert your lamps without touching them, but if you do, and even if you don't, wipe the lamp over with the alcohol to remove any grease that may be left behind. Should substantially reduce the number of hot spots you get.
 

Radman

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Chris15 said:
My advice is to get some isopropyl alcohol. Definitely try to insert your lamps without touching them, but if you do, and even if you don't, wipe the lamp over with the alcohol to remove any grease that may be left behind. Should substantially reduce the number of hot spots you get.
Just a thought, what is the best material to use with the isopropyl? We just use a brown paper towel from the bathrooms. Is there a better cloth for thos?
 

Chris15

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Radman said:
Just a thought, what is the best material to use with the isopropyl? We just use a brown paper towel from the bathrooms. Is there a better cloth for thos?

I don't think that there is a specific cloth you need to use, but I would avoid paper based things simply because they have a tendency to disintegrate and leave bits behind. Obviously it is preferable that the cloth be clean, using oil soaked rag kind of defeats the purpose of cleaning. But really, most things should be suitable if you are careful to ensure that there are no bits left behind.

A warning though that I forgot last time, the alcohol residue will burn up the first time that it gets turned on after cleaning. This is to be expected and should not cause long term problems.
 

Chris15

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If I recall correctly, industrial wipes like they use to clean surfaces in medical type places, the ones that come in a baby wipe style container, are in fact a cloth soaked in isopropyl alcohol. You might be able to find some somewhere and then you have solved two problems at once. You have the alcohol and the cloth to use with it. There is a thread on the use of such wipes here.
 
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Dustincoc

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I prefer to use the cotton pads (the round ones) they sell st the drug store to remove makeup to clean lamps.
 

ship

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What explodes out of a lamp going up will have limited safety issues to the set - just to the people below. Less the hot glass than the glass itself in falling in large enough chunks as opposed to small pieces that would shower out of it. Yep, you could get injured by other than weather tight fixture in shower of glass, but not so much as a large chunk of it falling and cutting off say one’s neck.

Many ways for a lamp to go bad, one of my favorites in collection is a incandescent 1,500w lamp that had it’s filament explode out of it and the glass around the filament quickly cool around the hole as if bullet in slow motion thru fabric - the glass around where the filament came out retains a hole with the bulb in a hole bent around that hole. The opposing side of the mind you incandescent lamp forms a sort of “Killroy was here” type pucker image in due to the gasses sucked out of the lamp that fast, than cooling just as fast, the also molten temperature glass on the opposing end from where the filament escaped collapsed inward in that shape. That’s an incandescent lamp and you could have touched it in it in the oil from the skin effecting the glass.

Lots of reasons for a lamp to explode, not always due to touching it. Have another example of a touched lamp where as opposed to blowing up as if balloon before explosion, where the filament was just blown by way of reflecting away from the oil in where the heat from the lamp now goes, that the filament simply stretched to the extent that it penetrated the glass on the opposing side. Still works, just that the filament itself bubbled out in the glass in totally encasing itself within the glass and bubbling as blob of filament and glass outside the normal dia. of the glass. Other times there is white finger pints etched into the glass of a lamp or a bubble. Touching a quartz glass halogen lamp does not always cause it to explode and in fact could be less likely to make a lamp explode than some over voltaging or spike conditions - this especially during already warn filament conditions.

As for toweletts, cotton pads should leave more lint than the average kitchen paper towel. The washroom paper towel could often be really good for cleaning a lamp - depends upon how stiff it is. Rub the paper towel and note any lint that rubs off and or becomes air born. Lots of industrial towels on the market same rule with them in what is lint free or not. Kleenex tissues would tend to leave behind lint which is not good for the quartz lamp. Lens cleaning tissue will also tend to work well - really well. Isopropyl Alcohol towelettes come with moving light lamps and can be bought thru suppliers such as Grainger. Otherwise a spray bottle full of it and the towel will work fine.

Not going to start a fire - the glass and lamp will cool far to fast to do so other than perhaps on an open faced fixture that does not have a screening of direct contact of the hot part of the lamp to what’s combustible. Set that fixture on the stage face down and turn it on and you are much more likely to cause a fire.

Makeup cleaning sponges on the other hand might work well.

While shopping for towels to clean, get some powder free latex medical gloves (non-latex for the women folk.) That keeps the lamp clean while touching it as long as the gloves are clean.


Lamps explode at times, wouldn't be too worried about the exploding lamp causing a fire. If the glass were close enough to cause a fire, than it under normal operating conditions would also cause a fire.
 

RGermain

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I don't think that there is a specific cloth you need to use, but I would avoid paper based things simply because they have a tendency to disintegrate and leave bits behind. Obviously it is preferable that the cloth be clean, using oil soaked rag kind of defeats the purpose of cleaning. But really, most things should be suitable if you are careful to ensure that there are no bits left behind.
A warning though that I forgot last time, the alcohol residue will burn up the first time that it gets turned on after cleaning. This is to be expected and should not cause long term problems.


Personally I find the best way to avoid exploding lamps is to wear either nitrile or latex gloves (nitrile is your best bet because it lacks the natural proteins that latex has that cause allergic reactions), and if your really freakish like me you scrub your hands real good before you glove and double glove to eliminate almost all posiblity of getting any oils on the lamp.
 

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