I have a Steinel temperature controlled heat gun that I use for this same purpose. It can be adjusted as low as 160 F, and as high as 1,100 F, but similar to what you found at 212 F, I found it works best on plastic right around that temperature (210 in my case). I have had a couple of warped canopies and car chassis that have been fixed with it. Definitely an essential tool for model building...and I use it at work also for heat shrink tubing and solder sleeves. Also works well for softening Nylo-Flo tubing just enough to get to slide onto pitot and static system fittings easier.