I don't think heating the glass/epoxy is going to help your cause. It could make matters worse. What I have used successfully on this problem is a c clamp to squeeze together the part of the seam that is sticking out. When you get it lined up, tightly wrap liberal amounts of fiberglass reinforced tape around the seam. At that point you can take the clamp off. Usually the seam will stay put but if it doesn't put the clamp back on while you glass the interior seam.

: I'm struggling to match deck to hull, the deck has spread to give a max error
: of around 3/8" on both sides. The worst place is near the bow and stern
: where the shallowness of the hull shape makes it near impossible to
: squeeze it narrower, using a spanish windlass setup I can just about force
: it but it obviously springs back once the compression is removed, )the
: expoxy is completely cured).
: Has anyone tried using heat to soften and 'reset' the epoxy ? I've
: experimented with a hot air gun and found the localised heat can overcook
: the resin so the glass comes off.
: Andy