heat guns for shrinking elect connections

[Mr. Sandman]

I have one of these small butane flame-less guns by Anchor for shrinking those waterproof electrical connections. Personally I think they are lame. I use it because it is made by the same people who make the connections but it is slow and is a PIA dealing with these tiny cig lighter butane cartridges. Would a standard electric heat gun (110 volt) work or is it not hot enough? Is there an industrial or commercial tool to shrink these things tight? I was going to use a propane torch but I can't get a flame in there and don't want to damage any insulation on the wire.