mtp wrote:so i take it that if you repair an area with body filler and sand it smooth you do not want to reach any bare metal?
When doing filler work it is expected that you will sand to metal in places. You are trying to fill just the low area and feather the filler out into the surrounding panel.
mtp wrote: Or is that you dont want to reach the bare metal after applying the primer?
Once your repairs have been completed and sealed with epoxy (my choice) you spray 3 - 4 coats of 2k primer and then block sand the panel straight which should happen before you reach your epoxy layer. This is why the guide coat is so helpful. Once the guide coat has been sanded off you move on down the panel.
mtp wrote: . . . im using a foam block sander and have the feeling that its too soft not really getting the area flat rather forming around the high spot if that makes sense.
The first round of block sanding should be done with coarser grit so it cuts easier and flatter plus a long sanding block that is firm and straight. Most of the first round of 2k will be sanded off the car by the time you get it straight. Also remember not to push too hard on the block and change your paper often.
mtp wrote:im working on a rounded area of the rear quarter panel of my miata. thanks all.
For tighter curves and rounded areas use a round shaped or narrow rectangular durablock style sanding block.