Five minutes of fame

[Fingal]

Perhaps heat and the quality of rubber has something to do with it. Given that Poisson's ratio of rubber is 1, on heating the rubber O ring will try to expand in all directions without any volume change. On cooling it should revert to its previous shape and state of stress which is dependent, inter alia, upon how tight the cap was. The loading, unloading stress strain curves exhibit hysteresis, ie energy is lost, which may contribute to eventual plastic behaviour, ergo permanent expansion.....Over tightening may exacerbate things.............

A good letter to YM. A pity it wasn't acknowleged.

Jings! I faintly remember Poisson's ratio, but it was about 40 years ago...

I have never felt the gearbox being noticeably hot, but it's not something I've deliberately checked regularly. I'll maybe start to do so.

All sounds a bit fishy if you ask me,

[Ghillie]

Indeed,

I noted that the fish courses on a restaurant menu I espied once came under the heading
"Poisons"......

Doubtless an O ring had failed on some piece of cookery gizmo, so it was probably apposite.