Varian states this explicitly in their general info about diffusion pumps.
I'd have to hunt for the web page, but I found it in a general search
for info about ultra-high vacuum. Let me know if you have trouble to
find this or more detailed references.
Alternatively, basic physical chemistry leads the way. Trust this! In
absence of knowledge of errors, believe the handbooks that tell you at
such and such temp+pressure this is point of spontaneous combustion. If
you want to prove them wrong, be forewarned; more than just a few others
who have tried are now dead, so careful what you wish for.... IMHO.
:0
You can more easily contact manufacturers of pump oils and ask the
technical representatives. They generally know this. You will find
they have a selection of oils and explosions are key in their thinking
process as to specific choice of oil(s). This is in fact one reason
some manufacturers are hesitant to get involved with amateurs building
their own systems.
I would have to think a little on the total explosive force of a
completely filled pump, but typically it is not so terribly much.
On the other hand, if it happens to you, the fun is over and you'll
have a rather expensive junk heap on your hands.
A more likely scenario is that the oil burns up all over the place
and you will have a very unpleasant cleanup job. This also disrupts
the fun.
Both explosions and burns are readily preventable and this was actually
my point.
Dominic-Luc Webb
