I have been experimenting some problems when melting the metal
in the centrifuge machine crucible with the compressed air/propane
torch which practically keeps going off the whole melting process,
Sometimes when the metal is already molten and I am about to
strike the centrifuge arm the torch goes off.
I'd bet that flame gasses, hitting the inside of the crucible, and
bouncing back and litterally blowing out your flame. Move your torch
tip a bit further back, and perhaps a bit to one side and down, so the
flame returning back out of the crucible is clearly well to the side
of the torch tip. That may help.
The straight propane, Bernzomatic torches, at least the ones with
the rigid torch assembly attached straight to the tank, can have the
problem where the liquified fuel doesn't completely evaporate to a
gas before reaching the orifice of the torch, which then clogs it and
blows out the torch. One the torch if fully warmed up, this happens
less, but it can be an annoyance with some of these types.
I would not like to switch to oxygen and propane cause my studio is
Might I mention that in general, the danger in an oxygen / propane
system is still mostly the propane tank, which you've already got now.
With an oxygen tank, there are generally two risks. One is that you
get an oxygen leak. When that happens, it simply means you waste
oxygen, but can breathe easier in your shop (grin). The leaky oxygen
costs you money, but that's all, unless there is already an out of
control fire, which will then burn more fiercly with added oxygen.
But the oxy tank wont' cause the fire. The main danger of an oxy
tank is simply that it's at high pressure. If you knock it over and
knock off the valve stem the high pressure tank will do a lOT of
damage. For that reason, gas tanks need to be secured, chained in
place or otherwise, so they can't tip over. Do that, and they're
relatively safe. Your propane tank, though, if it leaks and fills a
room with enough gas, can cause a major explosion. Propane is a good
deal more dangerous to have indoors than an oxygen tank, as the risk
is a situation that's considerably more common.... a leak. Still, I
feel safe enough to have it in my own home shop, and so do many
others. Natural gas, either in a tank or through municipal service,
is considerably safer than propane, though still not totally safe.
Unfortunately, most residential gas service is not at high enough
pressure to run a torch well.
Hope that helps.