I have a 2006 Roush Mustang and just did the wheel wells with 3M Underseal Rubberized Undercoating #08883. On dry metal (no rustproofing) and on plastic, it drys fine but in the rear where Ford sprayed partial undercoating, it won't dry. It probably is not compatible with the undercoating. The instructions state to wait 1 hour before painting and I waited 24 hours. Does anyone have any ideas. I have had fans on it constantly and had heat on it for 24 hours. I hate to have to wash it off with lacquer thinner.