When you paint furniture, one of the most important steps is sanding. Note that every piece is different, this is just a general guide (metal sandpaper grit guide) to help you understand the difference between sandpaper grits. We highly recommend buying industrial grade sandpaper. If you try to go the cheap route, you’ll end up spending more time changing the paper than actually sanding, which will most likely cause you to end up spending more money.
These numbers are measured by grit size and the number of grit/grains per square inch. Note that projects usually start with coarse sandpaper and then move to finer sandpaper as the project develops.
40–80 Grit
Coarse. 40 to 80 grit is for heavy or coarse sanding to help remove scratches or blemishes. While rough sanding is okay, take your time when using low-grit sandpaper as it may show noticeable scratches or swirls in the wood. It’s better to use low grit on surfaces that have an old thick layer of paint/stain on them or when the surface has a lot of nicks and scratches. Note that you don’t always need to start your project with this girl. As mentioned above, this is mainly used to remove old paint or scratches. If your piece is in great shape, or has a thin layer of veneer on it, there’s no need to use a grit this low, so just jump to 150 grit or 220 grit (if that’s the case).
100–150 Grit
Medium. 100–150 allows adequate paint and/or stain adhesion without making the work too smooth or rough. When you’re painting or staining a piece, make sure not to exceed 150 grit. If start getting above 150, it starts to seal the wood, making it harder for the wood to absorb paint and/or stains.
180-220 Grit
Very good. 180–220 grit is primarily used for sanding the finish or sanding between coats. It’s also great for pain! In some cases you can use 180 to 220 grit to rough up a piece ready for painting, but these are usually not used until after the first painting. Most of the time we use 220 grit because it’s a bit smoother. These are also great for removing any scratches that the low grit used earlier might have caused, but make sure you do this before you start painting or staining.
320–400 Grit And Up
Very good. 320-400 grain size and above. These higher grits are used at the end of the project when you’re applying topcoat or sealer. Ypu lightly use a piece of 400 grit sandpaper or a sanding block, and work over the paint/stain for a super smooth finish.
Conclusion
When using sandpaper, make sure to apply even pressure throughout to keep the finish nice and level. You’ll also want to make sure you sand with the wood grain so you don’t create any unwanted scratches or blemishes.
