They make a product called "Lab Metal" that you can fill pits with and it will take the heat of powder coating. A little hard to work with compared to regular filler but works OK. Several powder coaters around here stock it for customers. I find powder coating to be cheaper than painting but most probably don't go through the steps I do and use the premium materials. A frame, driveshaft, rear end housing, springs, A-frames (Camaro sub), and maybe a couple small parts run a little over $300 to powder coat; a paint job including cleaning and prep will run at least twice that or more. With all this said, I prefer a painted frame.
