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Say the front page link reminds me...
When i was working as a body shop monkey, i was forced by my boss to BRAZE (you know, with an oxy-acytalene torch and a stick of brass) panels together on doors and fenders, right? Well, that kind of heat both destroys the strength of high tensile sheet metal that cars are made of AND warps the crap out of everything.
So i used a sandblaster trigger and hose to suck water up, and blast it onto the red hot spots, hoping to quench the steel and keep some of the strength, and keep it from warping too bad.
In the process of doing this, i'd blast the water onto a red hot spot, keep it blasting until cool, and a couple times i noticed a white flake of somethig being blown off. I thought it was flux from the brazing rod. One time i stopped and caught it. It was ice. Below ambient cooling with no power source besides compressed air forcing the evaporation of water spray.
Total temperature drop from about 1,500 degrees F, down to below zero, in a matter of seconds.
Drawbacks for use in anything besides a body shop:
Water gets everywhere.
It's absurdly loud.
Waste water goes down the drain.
Enough compressed air to do the trick requires an industrial class compressor.
But i thought some of the thermodynamics geeks in here might get a kick out of that story.
When i was working as a body shop monkey, i was forced by my boss to BRAZE (you know, with an oxy-acytalene torch and a stick of brass) panels together on doors and fenders, right? Well, that kind of heat both destroys the strength of high tensile sheet metal that cars are made of AND warps the crap out of everything.
So i used a sandblaster trigger and hose to suck water up, and blast it onto the red hot spots, hoping to quench the steel and keep some of the strength, and keep it from warping too bad.
In the process of doing this, i'd blast the water onto a red hot spot, keep it blasting until cool, and a couple times i noticed a white flake of somethig being blown off. I thought it was flux from the brazing rod. One time i stopped and caught it. It was ice. Below ambient cooling with no power source besides compressed air forcing the evaporation of water spray.
Total temperature drop from about 1,500 degrees F, down to below zero, in a matter of seconds.
Drawbacks for use in anything besides a body shop:
Water gets everywhere.
It's absurdly loud.
Waste water goes down the drain.
Enough compressed air to do the trick requires an industrial class compressor.
But i thought some of the thermodynamics geeks in here might get a kick out of that story.