On 12/20/2013 2:08 PM, David Billington wrote:
On 20/12/13 14:43, dpb wrote:
....

_IFF_ (the proverbial "big if") this is actually occurring (of which
I'm still not convinced there's not something else at play) I doubt
it's actually much temperature related (at least from internally
generated heat; the hypothesis of starting w/ something hot from
exposure to sun or the like aside)at all but some sort of outgassing
or the like that's generating the internal pressure rise with some
modicum of additional heat perhaps. If this were such a major issue it
seems the cans would have all sorts of warnings and it wouldn't need
just a handwritten sign on the mixer at the local co-op.

I posted the warning message printed on the lid of some cold galvanising
paint I have, it would be difficult to miss when opening, on the 20th
and it said not to shake and also that pressure build can arise due to
moisture contamination. I wonder if the zinc reacts with the moisture to
produce some zinc compound and hydrogen resulting in a pressure build up
in the can.
....

Perhaps but that's a completely different system than the Al paint of
the subthread discussion...

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