I have found those little self-igniting butane torches are very handy for this type of thing. The ones you can refill from a regular lighter butane can are the ones I am talking about. Very small, like an overgrown lighter with a nozzle. Make a small curved metal heat shield so you don't set fire to the surroundings and you are good to go. I mostly use one of the big ungar hot air guns at work, but sometimes space is limited and the mini torch is great.