Originally Posted by wyomingclimber
MartinSr: That's an interesting concept. I'm going to give it a try tomorrow. I also have a DA with a soft interface pad, but I wonder if that would just be opening a can of worms. I may try it when I move to 320. I'm at 220 now.
Z28: I do have that block and it's the first thing I tried. Because the severity of the curve varies so much, I had to keep bending the block back and forth, which caused wrinkles in my paper, which in turn caused a few disastrous grooves.
Part of this may be the fact that the paper doesn't stick very well. Can't get my garage over 49F. Wyoming is a winter wonderland you know...
That one looks like fun, I have to wonder if your primer is fully cured being that it is so cold, it might make it too soft for blocking hence the gouging.
I also had problems with Omni primer not setting up, but if it's not clogging your paper then it's your technique.
I'm not a fan of durablocks, I find them cumbersome to use, and I never found it to be a asset on anything outside of scuffing the inside of a truck box floor.
I would use 8" straight block around the corners, then I would use a soft 5" around the apex edges to smooth out the roundness, patience is key.
If you feel confident enough to use a DA, make sure it's a finish DA and not a grinder/DA sander.
A palm sander, or a Hutchinson works well, 5" disks might make it easier if you have one, but 6" works too.
220 grit is perfect for sanding primer that is going to be re-primered, but if you are going to go to a sealer or a base coat next step, stick with 320 or 400.
Or you could go 600 grit wet sand with a softer backing pad to finish it off, if you soak the paper in warm water and add a touch of dish soap it should help avoid gouging the primer.