was thumbing through his book again (never leaves the bog) and there was a note about linseed oil and cottonwool can spontaneously combust anyone ever tried this? sounded interesting looks like i might have to get some linseed oil...
Not sure it'll do it on demand, but I have read of it in relation to woodworkers, French polishers, cabinetmakers and the like. rags used to apply wood finishes and then thrown in the bin have been known to spontaneously combust.
I tried a cotton rag with - I think - danish oil ...a goodly while ago...
I wet the rag thoroghly in the oil then I stuffed it ino an old syrup tin and left it in the sun....several hour later I came back to it and it had burned to ashes.
I cannot tell you how long it took - but it worked!
These days all my oily rags get put in the fireplace after use!
What happens is that when the linseed oil is ozidized the process is exothermic. If the rag is suffiently "dense" the heat may accumulate until combustion occurs. So Johns experiment was with pretty much ideal conditions to obtain combustion.
Danish oil can have the same exothermic reaction as linseed oil. Whenever I finish coating my paddles or gunwhales I always lay the rags flat and on the floor away from other combustibles just in case. I think if you have sufficient number of scrunched up cloths all together then they might combust. Might be a bit like watching paint dry though if you're waiting for it to happen? You could add a little extra heat using a heat gun to see if you can speed up the reaction?