This stuff is great. You can work with it in the shade for quite a while then stick it the sun and it cures in about 15 minutes (on a cloudy day in Tucson, probably 5 minutes on a clear day). It spreads like warm butter. Since I am more concerned about the cosmetics on the radiator duct than weight I am using the body filler to smooth it out. I really need to work on my glass technique.
UV Curing Body Filler