Hi Bob, Pressure? Diesels don't have "glow plugs" anymore? ... Gosh! ... I must be old! There are a couple of parameters to be aware of here like "flash point" and ... shoot - I forgot what it's called - but it's a region of flammability determined by the air/fuel mixture ... any fuel is only flammable within a certain range ... too low/lean a mixture OR too high/rich a mixture and it won't ignite. Sez RonL. (Who once or twice upon a time [unofficially] helped his grandfather with explosion demonstrations for the US Government. One of the demonstrations involved filling an ordinary water glass about 1/2 full of gasoline, holding it in our hand, and then placing an automotive spark plug inside the glass (just above the fuel) and asking the audience what would happen if we set off the spark plug .... and then doing it! Nothing happens ... the mixture has too high a concentration of fuel at the point we were applying the spark - so it could not ignite. It DID, however, get the audience to move back a bit!! Ah yes - Gramps was a bit of a showman ... and a "trained professional" with this stuff - whereas *I* am not.... ;-) -----Original Message----- From: Bob Davis [mailto:bobd at members.evolt.org] I have been told that if you drop a lighted match into a can of diesel fuel (or kerosene/parafin for that matter) that it will not light. They need to be aerosolized (sp?) to ignite and prefer to ignite not by flame but by pressure.