Hi, new to the forum. Getting ready to do the final sanding of the primer on my restoration project and have a question I couldn't find the answer to. This is my second overall paint job, my first one was 12 years ago and my memory is foggy on some of the details. I made a folder with some notes and advice I got prior to that job and was reviewing them and came across a note saying for the final grit, wrap paper in a rubber block and sand "in one direction only". I couldn't find any other mention of this in the other primer sanding topics I had looked at.

What is everyone's preference on hand sanding technique for that final grit?

Thanks,
Steve

How would you wrap paper in a rubber block?

I use X pattern for cutting, straight back and forth for final finishing. If any sanding scratches do happen to show through they will at least be uniform in direction.

Final Wet Sanding of Primer:

3M Dry Guide Coat
600 grit Wet/Dry wrapped around Motor Guard soft block
Sand any direction you want but be sure all the guide coat is removed.

At this point any straightening or flattening is done and you are simply refining the scratches before applying paint.

2'nd THIS^^^^ if you don't have the soft sanding block be creative, a firm house hold sponge will work. I've used a scratch pad folded then paper around it hold it flat and sand away.
Jay D.

68' is correct, if using 600 or above it won't matter
which direction. But that's only for "final" sanding.
If you're going over bodywork or any irregularities
then a coarser paper is needed and usually straight
sanding in a "x" pattern is used.
Long straight strokes.

Thanks for the replies. This is the final sand and I just wanted to confirm what I thought I knew. I have a hard time remembering what I did last week anymore much less a decade ago. I have a pack of those Motor Guard soft blocks, forgot about them until it was mentioned above.

Thanks!

i am curious what the experienced people think about the 3m soft sanding pads?

i assume even though scuff pads, these pads and sandpaper have a rated grit, we all can sure see the difference when sanding primer and the scratch it leaves.

i have experimented at the end stage just to learn a bit with 600 wet. i think using a loose piece of sandpaper with your fingers is still a bad idea even if you think you are just skimming the dirt, etc.

so i use those soft pads and it seems to do the trick.

but why im asking is because those sanding pads are flexible so they seem nicer than scuff pads in transition areas like wheel wells?

I think your cutting a fine line with the pads and scuff pads both will do a specific job one better than the other and your absolutely correct about the fingers but they do work in certain situations. I think that the sand process is the one most tedious part about a paint job, you just have to decide the right tool for the job. as JC says its not custom painting its custom sanding.
Jay D.