Maybe I've just had bad luck with Versa Tools...Had three of them crap out on me. I finally bought a Snap On butane soldering iron. It also has the hot knife attachment. Works like a champ. Can run much hotter than the Versa too, so it cuts faster. It's expensive, think I paid like 120 bucks or so, but it's worth it... Made in the UK, very well designed. Plus lifetime warranty if it ever breaks. I use that thing all the time for various projects and fixes.
Here's a link:
http://buy1.snapon.com/catalog/item....re&dir=catalog