"riverman" wrote in message ...
I'm wondering if it was a combination of overheating and the tube sitting
so that the top section was on its tip. Do people pay any attention to how
they store their tubes? On their sides, or with the butt end downward
(especially for the tip section)?

--riverman

At home mine are always stored with the tube vertical and the tips toward
the ceiling. In the car? however I can fit them in!

Op