Well, the water bath does keep the skin cooler, but that is because the
water increases the tanks ability to shed the heat produced in the gas. The
heat goes from the gas to the tank to the water. Over filling the tank and
letting it cool could over stress the tank. Not a good idea, IMO. Like you
say, much better to fill it slowly enough for the heat to dissipate to the
surroundings, be it air or water, and you get a full tank. Those tanks are
already under tremendous stresses without not only going over pressure, but
doing it when the tank is hot and the tanks strength could be weakened with
enough heat.

mike

"Grumman-581" wrote in message
...
"mike regish" wrote in message
. ..
In researching this, I found scuba divers complaining about "hot fills"
where the tank is filled too rapidly and when it cools down they are left
with a less-than-full tank.

I suspect that the water bath approach just results in the skin
temperature
of the tank being cooler whereas the gas hasn't really decreased that much
in temperature... Thus, they're still getting "hot fills", they just don't
notice it... The easiest solution to hot fills is to just fill it higher
than normal and when it cools, it's at the target pressure... Or you could
just do it right and slowly fill the tank...