>  I once caught the nose of a very expensive Olympic
>slalom kayak on fire by mixing too hot a batch of resin to get the endpour
>for the bow to set up quickly.  Exothermic reaction I was told.

Chemists. The setting reaction of polyester resin with
methylethyl-ketone-phosphate catalyst releases heat; put too much
MEKP in, or have too large a solid lump, and it gets so hot it splits
and smokes... a bit more and up it goes. A reaction which PRODUCES
heat is endothermic (internal heat), one which takes heat-energy to
induce is exothermic (outside heat). Ask any biologist! The chemists
have it wrong.