Leo Lichtman wrote:

"Tim Wescott" wrote: (clip) That may be the one (partially) true claim,
actually.

Hydrogen remains largely transparent as it burns, so it emits very little
light. (clip)

^^^^^^^^^^^^^^^
Tim, only if you DEFINE temperature in terms of radiant emission can you
cling to that statement. Are you aware of the deaths that have occurred at
the Indy Speedway because alcohol flames are not visible in daylight? If a
torch truly produced a low temperature flame, it wouldn't be worth s**t for
welding. It isn't necessary to heat some other surface in order to have
heat. One of the laws of thermodynamics is that heat ALWAYS flows from a
higher temperature to a lower temperature. If the flame were really cool,
it COULD NOT HEAT ANYTHING TO A HIGHER TEMPERATURE.


They were specifically talking about "radiant temperature". Assuming
that means the temperature you read with an IR radiometer then it could
indeed be low, depending on your technique and the radiometer.

You clipped out the part where I was saying that I wouldn't stick my
hand in the flame -- having gone through more than one bottle of
isopropyl alcohol to fuel a bullet-making and general solder-casting
operation in my bedroom when I was 13 I can attest to the heat of an
"invisible" flame.

I'm just lucky I didn't burn the house down -- particularly since my dad
was assistant chief of the fire department _and_ on the board of directors.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com