Once your body work has been sanded and finished with 80 grit, your edges must be sanded smooth using 150 to 220 grit. Paint edges left behind from grinding or sanding are rough, which may result in a lot of priming and blocking. By using a DA sander to layer each layer of coating at least 1/4” will eliminate the hard edges that may show up after painting and make the priming and blocking much faster. The closer you can get the repair area to perfection before priming, the less priming and blocking that will be needed. This will save time and money.
Here are the steps to this point: (We’re assuming that both sides of the dent can not be accessed. Therefore, we are using a stud nail or similar dent repair method.)
- Properly Clean Surface
- Grind or Sand Area (newer thin metal should have the coating removed using a DA with 36 grtt sandpaper.) This will reduce the amount of metal removed throughout the repair process.
- Properly mix body filler using a spreader and a mixing board.
- Blow the repair area off with compressed air and apply the body filler to the metal. Do not allow your body filler to overlap onto the painted surface.
- Block Sand the filler before completely drying with a cheese grater or with 36 grit sandpaper. This will reduce the amount of sanding. Once completely hardened, shape the surface with 36 grit leaving the surface slightly higher than the substrate. This will allow additional sanding with finer grit to remove the 36 grit scratches.
- Apply guide coat to the repair area to help identify low areas.
- Sand the repair area using 80 grit sandpaper to remove the rough 36 scratches.
- Now you’re ready to feather edge the surrounding paint edges as mentioned above. I usually use 150 grit on a DA sander to level or layer the surrounding paint eges and scratches.
Next, you’ll be ready to apply finish glaze and have the repair ready for prime and block.
Below is another video that demonstrates how to feather edge a small repair area.