Most drywall projects should be finished with sandpaper in the 150-220 grit range, depending on the methods you use. Higher numbers mean a finer grit sandpaper and lower numbers are coarser.
Now you may be thinking "SAND AGAIN?!?" after just finishing the messy drywall stage, but a light sand with 150 or 180 grit sandpaper is very important. Whether you use a separate primer or self priming paint, both will raise the nap of the board making a slightly rough surface.
Most beginners skip sanding after priming, but it is a critical step. Sanding before painting gets rid of paper fuzz and lumps that would otherwise show through your paint job. At this point, you should also take care of any other imperfections by filling them with joint compound.
Sand the Primer
Let the primer dry completely, then sand it down before painting. Use very fine 220-grit sandpaper, and apply light pressure to prevent gouging the primer. Remove the primer dust with a quick brush from the shop vacuum, followed by a light swipe of the tack cloth.
Use fine grit sandpaper, between 150 and 180 grit, to achieve the desired results. Some drywall sanders include a vacuum attachment to collect excess dust and debris.
For your finish to be vibrant and not dull sanding after primer will ensure that the finish is not excessively dulled when you apply your paint top coat. You will typically use finer grit sandpaper and aim to achieve a smooth wood finish so that you get a fine appearing wood finish when you apply your topcoat.
The quick answer to the question, “Do I need to sand primer before painting my wall?” is YES. Primer should be sanded before you apply the paint.
When looking to sand a surface before applying primer, the best grit sandpaper to use is 320 to 400. Both these grits can effectively remove the existing primer and help you flatten the surface.
To aid in coverage when drastically changing paint colors, ask to have your primer tinted to around 50% of your final paint color. A minimum of two coats of PVA primer is necessary when painting new drywall in order to prevent the paint finish from looking splotchy and uneven after drying.
However, most professional painters will advise you to sand after primer. This is the most common time to sand, as it will give you a smooth surface when it comes time to paint. So, while you can sand before adding primer, you should always sand after primer, no matter your situation.
Most latex primers dry to the touch in 30 minutes to one hour. But for best results, don't paint until the primer completely dries—which can take up to 3 hours, depending on temperature and humidity.
Wet sanding 2K Urethane primer is best done with 400 to 600 grit wet/dry paper on a Durablock. Under most circumstances you will not need to DA sand over your work after wet sanding because wet sanding creates much finer scratches.
Coarse-grit paper like 80-grit isn't necessary because drywall joint compound nowadays is soft enough to be sanded down at up to 180-grit. Using coarse sandpaper less than 100-grit may leave visible scratches in the drywall mud compared to a fine-grit sandpaper.
Yes, you need to sand between coats of mud. However, perfection isn't needed on those first few coats. Knock down ridges and obvious bumps so that your next coat can be smooth.
Usually one coat of Kilz will be enough to cover any texture issues, stains, previous colors, and odors.
You're painting unfinished drywall or plaster.
Two primer coats are recommended in this scenario because much of the first primer coat will be soaked up by the wall; the second coat will replenish any primer absorbed by the surface and hide any flaws in the wall.
Most primers are dry to the touch within a few hours, but for best results, wait at least eight hours before applying your final coat of paint over a water-based primer and 24 hours before painting over an oil-based primer.
Ryan said that by taking a surface to 180 grit or finer before applying primer, top quality primers should fill the surface without issue. Problems arise only when a primer is asked for “too much work” and to fill a deeper surface, he said. Fillers and glazes can present similar issues.
For heavy sanding and stripping, you need coarse sandpaper measuring 40- to 60-grit; for smoothing surfaces and removing small imperfections, choose 80- to 120-grit sandpaper. For finishing surfaces smoothly, use a super fine sandpaper with 360- to 600-grit.
Yes, but not in this case. Moving up in the grit will cause the "bite" the new application of primer gets on the substrate to be less. So in this case it might actually hurt. Most build primers don't look for anything more than 80 or 120 on the substrate.
Q: Can I paint directly on drywall? A: No, after you are done hanging your drywall, you need to make sure that you mud and primer it before applying any coat of paint. After all of those steps have been complete, you can begin the process of painting your drywall.
It's important to prime after new drywall installation. The new surface will be porous and will absorb the color of the paint. Primers will also cover the joint compound and provide a good base for texturing or painting over skim-coated drywall.