Bryan's suggestion will certainly work Tom. Mr. shrink has a lot of power. But, if the bend is over a fairly
short section, it can be done with a wood fire. Supported both ends, with the bend up, and heat under the
bend. You'll need supports either side at more or less the straight point. Much slower, but can be done
with what's around and handy. I haven't done pipe that big, but it worked on a 40' section of 4". Once it's
nice and hot, it just slowly settles under it's own weight.
Good luck with it.