I recently started working on my '66 Mustang coupe that needed some serious attention. I have it parked in my back yard covered with a car cover but have noticed some rust starting to show on the top surfaces. I decided to sand it and applied some primer with a regular spray can. Did not like the outcome and was wondering if i can use automotive acrylic primer using a spray gun. Or do you have to do this in a air regulated room such as an auto body shop? Or should i take in to a body shop to finish the job i have already started?