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Post by jcgss77 on Jul 10, 2010 22:19:13 GMT -5
I am sorry if I ask this question in the wrong place, but I really want to hear what you guys have to say.
Is it okay to touch a tube with your bare hands? I know that they get hot, and they are cased in glass (duh) so I equate them in that manner to halogen light bulbs, where if you get your skin oil on them they develop a hot spot and burn out quickly. Does this happen to tubes also? Does getting oils on them reduce their longevity?
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Post by sumgai on Jul 10, 2010 23:41:55 GMT -5
Is it okay to touch a tube with your bare hands? If it's cold, sure. If it's hot, then do so only if your Medical Insurance is paid up - those burns might mean a trip to the ER is in your near future.  Nope. In fact, it shouldn't happen to any kind of glass bulb, not even the halogen types. The element gets hot, the glass deals with it, pure and simple. If the glass can't deal with it, it's not because the element inside is halogen or something, it's because the glass wasn't made to withstand "normal use and handling". One shouldn't have to "prep like a doctor for an operation" in order to change a freakin' light bulb! Nope. (this tirade left intentionally blank) HTH sumgai |
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Post by chuck on Jul 11, 2010 9:19:16 GMT -5
the "common wisdom" about the automotive halogen capsule bulbs and skin oils reducing their lifespan is that the bulbs burn so hot , and are sealed inside the headlight assembly with no airflow to cool them.
i cant say that skin oils do or do not shorten the bulb life , but it has been a well know tech tip in garages all across the land for decades.
i always play it safe when installing the capsule bulbs ... just in case.
but with tubes , i dont bother ... and have yet to have a problem
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Post by sumgai on Jul 11, 2010 14:01:30 GMT -5
A bit more research.... It turns out that I'm somewhat correct, the glass used to contain the internal structure is made of quartz. Now for some reason my education had a hole in it (obviously one that I didn't know about), and I believe that hole was just filled in. At least, so far as the Innerwebs is concerned.  It turns out that Halogen bulbs use a "hard glass" we all know as quartz. But what was lacking in our 9th grade science class was the fact that quartz is permeable. That's right, "stuff" can seep right through it, under certain conditions. From the topic of this conversation, you can probably guess that finger oils and the like are good candidates for such seepage. And it doesn't take any imagination to figure out that this is not a good thing for the gasses inside the bulb. And if our oils can get inside, doesn't that mean that whatever's already inside can get out? Well, that comes down to a matter of heat. It is hotter inside, and in theory, the inside of a smooth concave surface will distribute heat more evenly than the outside. On the outside (the convex side) heat can gather in a spot. This intensificaton is what causes the quartz to forget its job description, and start leaking. By the time anything can get out, the damage to the innards has already been done. Economics plays a role here. Glass made to withstand this potentiality would cost more, would be heavier to handle, and would act as an even stronger filter on the emitted lightwaves - less light would get through, making it less efficient for our needs. Overall, it would pay only from the standpoint of safety (Think Of The Children!!) or saving us from the aggravation of watching a $20 bulb go up in flames, all because we sweat like normal humans. Like I said, man didn't climb to the top of the food chain just so's he could don a pair of cheapie mechanic's/doctor's exam gloves in order to change a silly light bulb. This is the work of people who are too lazy to invent glass that can do the job, but without the aggravation. </rant> Thank Gawd all the foregoing is not true for our beloved tubes! sumgai |
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Post by jcgss77 on Jul 11, 2010 14:25:19 GMT -5
I second your last statement.
In my job, I deal frequently with halogen light bulbs, by manner of installing them into displays that I build for a large-name home improvement store which has a lot of blue in their stores. I don't ever touch them with my fingers, and they still burn out sometimes within a week. Needless to say, I don't and won't ever have them in my house.
I am very glad that tubes are actually well-made to withstand what us rough around the edge humans throw at them and still sound smooth.
I also appreciate, sumgai, and other knowledgable members of this forum, your technical this-is-how-it-works answers to our questions. It is good to have people in our corner who know the truth from a $3 guitar cable and a $45 cable, and other truths corporate USA won't let out.
I am assembling my valvecaster as we speak. info later.
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Post by chuck on Jul 11, 2010 15:10:34 GMT -5
ahhhhhhh ...
so us dumb ol automotive guys were wise to keep our grubby , oily paws off those cute lil bulbs all these years after all ?
.... amen on being thankful for not having to worry about tubes the same way ;D
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Post by sumgai on Jul 12, 2010 14:49:06 GMT -5
Did I mention that one can purchase cheapie (meaning, non-hospital grade) gloves that you'd swear are the same as the ones used for exams by nurses and doctors? Mechanics use them, or a version of them, all the time. Saves a helluva lot of soap and effort at quitting time, I can testify to that! All I can say is, particularly to jc, if you're handling sensitive stuff a lot, you should be using these things. Hell, I even use them when painting, or out in the garden (on the three days a year we have good enough weather to actually work out there), or anywhere I want to keep my hands relatively clean. I get them at Costco, about 8 or 10 bucks for pair of boxes of them. (150 pair in each box.) I just checked Costco's website, they've got the wrong price posted there..... either that, or else they just went up by a couple hundred percent, as I just got a batch back in February.  You can of course find them elsewhere, at various price points. Can't say enough good about 'em!  sumgai |
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You can of course find them elsewhere, at various price points. 