Wet Sanding – Wet sanding is often recommended because it reduces dust and can help achieve a smoother finish. Use wet/dry sandpaper and keep the surface and sandpaper wet during the process. Even Pressure – Apply even pressure and sand in a consistent pattern to avoid creating low spots or grooves in the primer.
Sanding after applying primer will help you keep the surface as smooth and flat as possible, eliminating any leftover bumps, dents, brush marks, etc. And that sometimes happens if you didn't' check it well before priming. Consequently, it'll help you to achieve a bright final coat and that's not dull.
DRY & RECOAT
Dries to touch in 20-30 minutes and is fully dry in 1 hour. When dry, surface can be immediately recoated, top coated, or wet sanded. For best results, allow to Primer to dry for 1 hour before dry sanding.
Sanding after applying primer should help keep your surface as smooth and flat as possible, eliminating brush marks, or extra little globs.
When the question arises about what grit sandpaper is appropriate for a wet sanding primer, 400-grit is sometimes stressed as better for wet sanding than for dry sanding. The reasoning here is that, when dry, 400-grit tends to leave sand on the subject, which can be troublesome as far as finishing work is concerned.
When looking to sand a surface before applying primer, the best grit sandpaper to use is 320 to 400.
To thoroughly wet sandpaper, many people suggest soaking it overnight in liquid. By doing so, the paper will not absorb any more moisture during the sanding procedure. If you can't soak the paper overnight, aim for at least 15 minutes of immersion before sanding.
P320 - P400 grit sandpaper
These grades are the last to use before primer is added, to ensure the surface is as flat as possible before application. A very basic tip - if you think you've spent long enough and it's as smooth as it can be - spend longer.
You can use an orbital sander to wet sand, but should take safety precautions to ensure that neither your tools nor you get hurt. Additionally, wet sanding normally makes fine adjustments to a surface, something an orbital sander may not help you with.
Apply 2-3 coats allowing 5-10 minutes of dry time between coats. For optimum performance, allow final coat to dry 1 hour before scuff sanding with #600 grit sandpaper.
Wet sanding requires specific waterproof sandpaper and is almost always done by hand. Because wet sanding is a finishing process, you'll likely use high-grit sandpaper, from 1000 grit to 3000 grit and above. Compare this to dry sanding, which typically begins with 600- or 800-grit sandpaper.
I usually wait 2 hours between coats of primer and a good 24 hours to start on the paint coats, which need about 4–8 hours between coats.
Waiting for the primer to be "through dry" is crucial. If you paint too soon, you risk all sorts of issues, from poor adhesion to uneven color.
Technically, yes, you can do that. Some circumstances don't require sanding the existing paint and primer before repainting. If you choose this route, the car's surface might show minimal damage like puncture holes, body scratches, dents, and cracks. The body will look smooth and mostly intact.
180 to 220 Grit Sandpaper: Finer grit sandpaper is great for removing the scratches left by coarser grits on unfinished wood and for lightly sanding between coats of paint. 320 to 400 Grit Sandpaper: Very fine grit sandpaper is used for light sanding between coats of finish and to sand metal and other hard surfaces.
Applying primer is a different ball game from applying the top coat, though. How thick should paint primer be when you first apply it? Well, the surface should have an even layer of coverage, but still expect to see the underlying colour showing through, you may need to apply two coats.
After the car has been wet sanded, you can break out the polishing compound. We have successfully used inexpensive polishes to bring the shine back to our paint. It can be applied by hand or with a random orbital polishing tool.
Yes, an orbital sander can be used for both rough and fine sanding.
After the primer dries, lightly sand away bumps and ridges using very fine grit sandpaper folded into quarters. When the grit of one section of sandpaper becomes covered with dust, switch to an unused section and continue. Wipe the wall clean with a damp towel or sponge and allow it to dry before painting.
The goal of sanding wood that has primer on it is to smooth down the grain that has risen while still leaving the primer intact so you do not lose the added adhesion that the primer will provide for the top coat. To sand wood with primer on it you should consider a finer grit sandpaper (like a 220 grit sand paper).
If you want to prep polyester primer in order to prime over it with another material, start block sanding with 80 to break it open and roughly knock the panel down flat and then do the majority of your blocking with 180 grit and finish with either 180 or 220 grit on a DA sander.
If you need it to dry quicker, pour the sand out on a large blanket or tarp and spread the sand out evenly in a thin layer. Set that in the sun. Weigh the edges down with rocks so it doesn't blow away.
Wetsanding allows you to remove any scratches that dry sandpaper may have caused without removing too much of the underlying material. It can also be a great tool for paint correction to fix any defects or imperfections from an uneven paint job and remove any debris that may have gotten stuck in the paint finish.
The best way to remove orange peel without sanding is to use fast cutting compound. Cutting compound is an abrasive paste that will erode an extremely thin layer of paint and wear away the orange peel in the process. Pick up some fast cutting compound at a local automotive or construction supply store.