Re: [TCML] unknown tube / halogen failure

[Jim Lux <jimlux@xxxxxxxxxxxxx>]

Frank wrote:
> Google Halogen lamp failures fingerprints,
> You can find what I was saying, it is no mystery.
>
> Here is an site that explains it clearly: 
> http://www.reference.com/search?q=halogen%20lamp
>
> Frank


The actual quote from wikipedia (which is what the site Frank gave the 
URL for cites as it's source) is:
"This extreme, localized heat causes the quartz to change from its 
vitreous form into a weaker, crystalline form which leaks gas."

That's a bit different than Frank's original assertion:
"It is due to the type of glass in Halogen lamps, the envelopes are 
quartz and the intense heat and oils will cause premature failure of the 
lamp due to *reaction with the quartz and skin oils* causing the lamp to 
lose its pressure. " {emphasis added)

And, like many wikipedia entries, there's no reference or backup for the 
assertion about transformations of forms.  Might well be true, but no 
way to easily find out.  Neither of the two cited references make any 
reference to handling. Searching for "devitrification silica" did turn 
up a reference to:
"On the Devitrification of Silica Glass
William Crookes
Proceedings of the Royal Society of London. Series A, Containing Papers 
of a Mathematical and Physical Character, Vol. 86, No. 588 (Apr. 25, 
1912), pp. 406-408"

And a NASA technical report:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720020893_1972020893.pdf


Interesting stuff.. learn something new every day.  Might well be that 
Wikipedia is wrong and Frank is right.

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