Pop wrote:
((snipped))


Ummm, nearly empty cans can collapse too - I've done it; not
completely, but enough it wouldn't reliably sit upright any
longer. One side collapsed more than the other.
Are you saying the expand/contraction of gasoline can also
collapse a can if it's full and air tight? I never thought of
that, but I can see it's possible I guess, esp inthe case of 45
or 55 gallons; it would be a fairly significant volume change I
guess.

No, I'm not saying that. Liquids don't compress,
so a tank full of liquid can never collapse. What
I'm saying is that you don't need to worry about a
55 gallon drum collapsing under any condition. It
might bulge or dimple a bit but that is all.

The old school trick of collapsing a metal can by
boiling some water in it, screwing on a tight cap,
and then letting it cool is fun to watch, shows
the power of air pressure, but is extreme. You
have water vapor dropping from 212 to a lower
temperature and condensing to liquid. That leaves
virtually no vapor in the can. That extreme will
never happen with gasoline in a barrel without
deliberate manipulation to cause it.


If you
: are really worried, when winter comes, open the
: top screw to equalize the pressure and then close
: tight, but there is no need for that, just taking
: some gas out every month eliminates any possible
: problem.

Right. Goog point.

Thanks for your thoughts.