Thank you everyone for your input on the matter. I apologize for creating this thread then disappear for a few days, just finished moving recently so life is busier than I like.
But back to the topic at hand. Just to clarify, I am not attempting to do this, nor do I need to. Unless of course it would yield really favorable results. The reason I created this thread was because the question of doing this safely came up in another thread (I can link to it if anyone really cares that much) and no one had a diffinitive answer with the accompanying science to back it up, so here we are.
Here's some science posted from another member here on the topic
"Like most substances, glass expands as it heats up and shrinks as it cools. It also has moderately low thermal conductivity. And it's hard but brittle. These three facts are why glass can crack when suddenly cooled. And ironically, the same principles allow us to make tempered glass extremely strong.
Imagine you have a hot, thick piece of glass. It's uniformly heated and thus is uniformly thermally-expanded. Now dunk it in an ice water bath -- the surface will cool almost instantly on contact, but the middle has to wait for heat to conduct away before it can cool. That creates an uneven thermal profile, where the surface is cold but the inside is hot.
As a result, the surface shrinks! Or it tries to. The hot inner glass prevents the surface glass from shrinking. This creates a powerful stress profile through the glass -- the surface is trying to shrink, but can't, so it is forced into tension. The hot core is trying to stay the same volume, but the surface is squeezing in, so the core undergoes compression.
Ok, so it's under stress now, so what? Glass has enormous compressive strength. And any confined solid subjected to purely hydrostatic stress (from all sides equally) is pretty much invincible. (You can drop an egg or a piece of fine china to the bottom of the ocean and the pressure will not break it.) Glass also has, rather surprisingly, enormous tensile strength -- in laboratory testing of ultra-pure specimens, tensile strengths over
one million pounds per square inch have been observed. Under controlled conditions, glass is actually much stronger than metal.
But real conditions aren't controlled, and as we all know, glass is incredibly brittle. The tiniest flaw or scratch on the surface is able to act as a
nucleation site for brittle failure. Once a fracture is initiated in stressed glass, cracks can spread and grow like a lightning bolt. Stress concentrates at the tip of the fracture, causing it to lengthen until the entire piece is cracked through. Sosurface glass under tension is very weak in practice. (Note that I say "surface" here. That's important later.)
So in our hot-glass-in-ice-water example, the surface is trying to shrink but can't, meaning it is suddenly under tension. And the core is put into compression by resisting the shrinkage. It's not hard to figure out which section of glass wins the tug-of-war -- the surface fails first. And a crack grows out of some microscopic scratch or flaw, growing and spreading until the stress is suffiently relieved or the glass is broken clean through.
That's why hot glass breaks when it's suddenly cooled. But there's a really cool way to use this effect to make glass
stronger.
"Tempered glass" is glass that has been treated with heat to make it stronger and safer. A large pane of regular glass is heated to the point where it is soft and able to yield, so it is able to very slightly flow and redistribute internal stresses. Then the surface is blasted with cold air, causing it to cool and rapidly shrink just like the earlier example. But this time, the core is so hot that it is able to harmlessly yield a little, preventing a build-up of tension in the cooler surface layer. It's kind of like how a paper clip can be bent in half without snapping. Hot glass has some ductility -- it's not brittle.
So now the pane of glass has this cool, shrunken surface layer, and a hot, expanded core, and minimal stresses (unlike the earlier case). Now the entire pane is allowed to cool a bit slower, so the core is able to re-harden and shrink. As the core cools, it tries to shrink, but now the surface glass won't let it contract. So the core develops a large amount of tensile stress, because it wants to shrink, while the surface develops compressive stress as it's pulled by the cooling core.
Remember, glass is exceptionally strong in compression. And the inner core can't be scratched by daily use, so fractures aren't initiated and the high "laboratory" tensile strength of glass is able to come into play. So tempered glass gets the best of glass's material properties, without the downsides.
In order for tempered glass to crack, the surface must be put in tension so a fracture can propagate away from a surface scratch. But it's already in compression -- meaning breaking tempered glass requires overcoming all that residual internal compressive stress. Thus, the failure point is dramatically raised.
http://chicagowindowexpert.com/2...
And in an extremely fortuitous turn of events, as soon as a crack does manage to penetrate the surface to reach the high-tension core, the entire pane of glass shatters into tiny pieces. All that trapped internal tension just needs a single fracture to get it started, and the whole high-stress zone breaks itself to bits. This means broken tempered glass makes thousands of small pieces rather than large jagged shards. This is a huge safety feature in applications like cars where broken glass may strike passengers in an accident.
I find this to be a marvelous concept. By putting glass under great internal stress, we make it more resistant to external stress! Rapid cooling destroys regular hot glass, but strengthens reallyhot glass."
......the salt/halide arcs need to run at a specific temp for them to operate optimally.....
......the top hid bulb manufactures(Philips/Osram/hortilux) don't recommend cool-tubes for this reason. The top fixture/reflector manufactures(gavita/pappilon) don't make a cool-tube also for the same reason. The top growers/ops don't use cool-tubes for the same reason...lol, see a pattern?.