"dave" wrote in message
...
anybody know the flame temperature of a gasoline "plumbers blowtorch" type
stove when it's burning blue? the kind in the center-left of this picture,
on the dolly...

http://machines.freehostia.com/sasge...s/photo63.html
babbitt_pouring06.jpg

I want to use it to pre-heat (heat soak) a pretty large piece of steel,
prior to brazing some stuff to it...


The maximum flame temperture at the tip of the inner cone will be about
1900C if you have full aeration - pretty similar for all hydrocarbon fuels
burning in air. Doesn't mean you can get a big piece of steel up to that
temperature - that will depend upon all sorts of things like heat transfer
rate and heat loss.