I had to look into why my outside flag light wasn’t pouring light onto my flag at night.  Lately the dusk to dawn trigger thingy has switched itself over to off and that might just be because of  “night walkers” being funny.  So I’m looking things over and I can’t see anything that would cause the light not to work dusk to dawn…except for the fact that the bulb could be burnt out (duh).

So I crank the cover lens off the thing and take a look at the bulb.  I have it in my hands and am looking at the bulb and the filament inside…it looks good.  I put it back into the socket and turn the switch on the timer dealie to “on”…the bulb came on!

So, now I have to cycle through all the other settings to get back to dusk to dawn…a really dumb old timer dealie.

I put the cover back on the light and walk away.  And then it hits me…I was not supposed to touch the bulb!  It shortens the life of the thing…dang!  How much longer will it last?  The package, when I bought it a few weeks ago, said it would last 2,000 hours…that’s 166 nights at 12 hours p/night…and I have only had it in there about a month.  Oh well.

That got me thinking about those type of bulbs.  They are on the headlights of cars to.  Halogen lights.  They say they burn brighter and last longer, but all of them warn you not to touch them with your fingers…I wonder why…and so, Bears Butt went to looking and here is what I found.

Incandescent bulbs, they type you have in your house that you screw into the bulb socket and these fancy little halogen guys both have “tungsten” filaments inside of them.  Tungsten is a pretty neat metal and can take a lot of heat.  Throw a bunch of 120 volt electricity at it and it will glow to beat the band and that is what causes the light bulb to put out light.  But it will actually burn itself up unless you remove the oxygen around it…that is why you have the glass encasement…the bulb…

In a house light bulb, when you turn on the light it glows like it is supposed to, but all the while inside the bulb, unknown to you, the Tungsten filament is slowly burning off and floating around inside the glass bulb in a vapor form and depositing itself on the inside of the glass, causing the glass (real glass) to have a dark spot on it.  Over time the filament gets thinner and thinner and then one day, when you flip on the light, if flashes and pooo00ffff, it goes out…the filament finally breaks.

Caution:  Don’t touch a lighted bulb…it will burn you!

In a Halogen bulb, the filament is also made of Tungsten, but inside the vacuum tube that surrounds the filament is pumped full of  Halogen gas.  When heated halogen gas is floating around getting all hot and all, and it grabs onto the tungsten particles that are also floating around inside the bulb and it deposits those particles back onto the tungsten filament…re-cycling if you will.  So, it lasts a lot longer than if there wasn’t any re-cycling, as in the case of the house hold bulbs.

Caution:  Don’t touch a lighted bulb…it will burn you!

Halogen bulbs last longer because they recycle the tungsten back onto the filament, but they deposit it at the coolest point of the filament…it’s still pretty dang hot at that spot, but it does it anyway right there.  In the meantime, somewhere on the filament it is still getting thinner and thinner and will eventually break just like the one in the house.  Dang it!  And they cost more too.

So, why shouldn’t  you touch a Quartz Halogen bulb with your bare hands (fingers)?  The oil and salts that are on your fingers will come off and stay on the outside of the bulb…These bulbs operate at a VERY HOT temperature…like 482 degrees Fahrenheit!!!!  That is hot buddy!  Well that heat transmits to the clear “quarts” outerpart of the bulb…and if your nasty old finger oil or salt is on the bulb it won’t allow proper bulb heat displacement and it will cause that portion of the bulb to get hotter or colder than the rest and it will disrupt the equilibrium of the whole process and the tungsten filament gasses will become disoriented (sort of)  and end up depositing themselves on the inside of the quarts glass and pretty soon…poooooffffff…the filament breaks and you have to go to town to buy another bulb.  And that will most likely be when you least can afford it and at a critical time, like the night of the 3rd of July, when you like to make sure your flag is lighted and in its best order.

Well, of course what you just read is my take on why you are not supposed to touch the bulb with you bare hands and I’m sure it is sort of close to the real why.

Bears Butt

May 21, 2013