As a matter of fact in ten years as a professional technician, (ASE Master
certification, MACS certified, Va state inspector class A, and the veteran of
many seminars and schools)  I HAVE cut exhaust pipes (NOT aluminum) used a nut
splitter (the proper tool) to break nuts (again NOT aluminum) when the 'hot
wrench' wouldn't work and used heat carefully to remove broken studs and bolts
from heads, blocks, etc. (Again NOT aluminum Read my lips-you cannot heat
aluminium close to the melting point safely-or do you have some kind of super
sensitive 6th sense the rest of us don't know about?  I'm sure I and the rest
of us would love for you to detail you experience in heating aluminum to close
to melting and having anything left to work with.
Patrick Foltz