Sanding is a very important step in preparing wood for staining or painting. It is done using sandpaper or a sander, essential woodwork tools. Although it is common with professional painters, you should incorporate it in your painting DIYs.

However, knowing what kind of sandpaper to select to perform a task can be confusing at times which is why you need to understand the various kinds of sandpaper produced and their uses is helpful.

So, do you want to paint wood but do not know what grit sandpaper for wood before painting? Then keep reading to see pointers to look out for so you do not need up ruining your wood and painting task.

What Grit Sandpaper for Wood Before Painting?

Before painting, use 120-grit sandpaper followed by 150-grit sandpaper on the wood. This sequence should be followed so that you can have a smooth surface for the paint to sit on, but care must be taken not to create a very smooth surface that will not hold the paint well.

What is Grit in Sandpaper, and What is it Used For?

Sandpaper is a simple tool made of sand and abrasive material attached to a strong backing paper. The amount of abrasive that comes with sandpaper is called grit which comes in different types.

This abrasive can be in the form of natural minerals such as garnet or synthetic ones such as silicon carbide and alumina-zirconia.

Grit sandpaper is used for a variety of purposes. From smoothening surfaces to preparing surfaces to remove paint, this abrasive is used on wood to perform various tasks.

It is commonly used on wood, but it can also be used to sand metal and other hard surfaces. Sandpaper can make your surface rough or smooth, so you should know why you want to sand before getting one for use.

Importance of Sanding Before Painting Wood

It is important to give your wood a good start to have a perfect finish. Hence sanding wood properly before any stain or paint is applied is crucial. Here are some reasons why:

To fix imperfections

Wood generally comes with rough edges, deep scratches, and cuts, especially old wood. So sanding helps eliminate all the flaws and even out the edges, so paint sits well on the wood.

To allow the paint to penetrate

A wood plane would close up the pores of wood while sanding would open them up, thereby allowing the finish, which could be a stain or, in this case, paint, to penetrate well.

To refinish after chemical stripping

When wood is to be repainted, chemicals could be used to strip such wood pieces off paint or old varnish.

However, chemical stripping does not do a thorough job in paint removal hence the need to still sand to completely remove the finish before applying a fresh coat of paint. Here’s the best best grit sandpaper for wood paint removal.

To remove mill glaze

Mill glaze is the shiny look that new wood trim has. If it is not removed, it could prevent paint from sitting well on wood.

So do not think new wood does not need sanding; it still needs to be sanded so this glaze or high shine can be removed, and the paint works well.

Types of Grit Sandpaper

One major thing to remember before purchasing sandpaper is that the lower the grit number, the coarser the sandpaper, and the finer the grains of sand or abrasive contained in the sandpaper, the higher the number of grit.

Grit number refers to the number of holes that contains the abrasive material of the sandpaper. There are six main types of sandpaper grit number, namely:

  • 40 grit
  • 80 grit
  • 100 grit
  • 120 grit
  • 220 grit
  • 440 grit 

These grits have ranges and might not come in these exact numbers, which is why they are broadly categorized into coarse, medium, fine, and extra-fine sandpapers.

They have different uses due to the varying grit number, which determines the material removal rate. The categories of the grit sizes are described below:

Coarse grit sandpaper

This is 40 grit sandpaper. It is designed for rough shaping of wood and removing previous paint or old varnish used on the wood before it gets repainted.

So if your wood was covered in light coats of finish such as polyurethane, you could use a 40-50 grit range of sandpaper to get it off. The coarse grit sandpaper is also best for deck sanding.

Medium grit sandpaper

This sandpaper ranges from 60- to 100-grit sandpaper. It is a primary tool for prepping and first-round sanding unfinished wood.

It is used for the final shaping of wood and removing marks left on wood due to planing. Its ability to smoothen out wood surfaces makes it efficient.

Fine grit sandpaper

120-220 grit sandpapers can be classified as fine-grit sandpaper. It is mostly used in home workshops for final sanding before applying any finish. It helps remove scratches left on wood as well.

This grit size can be used for a second round of sanding right before painting. Also, if you are about to use latex paint, this is a good option as it gives the wood a rougher surface to stick well to. 

Extra fine-grit sandpaper

From 240 grit to 440 grit can be described as very fine sandpaper. The 440 grit is also equivalent to 0000 ultra-fine steel wool. It is used between coats of paint to give a very smooth finish. It is a good tool for wood polishing.

It is always advised to begin your wood prep with a coarse sandpaper grit before switching to finer grits, so your paint sits well. What makes the surface smooth is the finer the sandpaper grits.

Other Things You Should Know Before Sanding Wood 

Before you proceed to that hardware store to buy sandpaper for use on your wood, there are some things you should keep in mind.

Select the right size of sandpaper grit

You must be able to differentiate between sandpaper grit sizes before using them on different projects. This number could be as low as 36 and as high as 400, but the higher the number, the finer the grit of the sandpaper and vice versa.

Choose the right coarseness for the project

Having a good knowledge of the grade used to determine the level of coarseness helps in selecting the right grit of sandpaper to use on wood.

Remember, different tasks on wood require different levels of coarseness. For instance, coarser grits can be used when sanding before painting, but finer grits are much better for preparing the wood’s surface for painting.

Know the best type of grit to use

Grit material also makes a huge difference in how successful sanding can be. For instance, garnet is best used for fine sanding, while flint is used to sand off products on the wood surface.

So you want to check to see what the manufacturers say the grit particles are made of before purchasing them for use.

Work with the right tools

Sandpaper is very versatile for use. However, when there is a lot to sand, you might want to use sanding tools to help you work faster and more easily. These tools include a manual hand sander or a belt sander.

Know when to stop sanding 

Sanding can be an endless job, especially when removing old paint from wood before repainting. However, knowing when to stop sanding is vital to get your desired results is vital.

So do well to check in the presence of low angle reflected light if the scratches or dents left on the wood have been erased or the entire paint has come off.

FAQs

What is 120 grit sandpaper used for?

120 grit sandpaper is perfect for sanding bare wood in preparation for finishing. This grit will remove any remaining roughness from the wood’s surface and help create a smooth, even finish. Be sure to use light pressure and work in small areas at a time when using 120 grit sandpaper.

Do you need sandpaper to paint?

Yes, you need sandpaper to paint. As with any surface preparation, sanding helps create a smooth base for your paint so that it can adhere better and last longer.  A good rule of thumb is to sand surfaces you normally prime before painting.

Can you use sandpaper to smooth paint?

Yes, you can use sandpaper to smooth paint. Sand your surface with a 320 or 400-grit sandpaper to get such a smooth finish. Before sanding,  remember to fill any holes as you apply the first coat. Then, sand with the fine-grit sandpaper and wipe away any dirt. This leaves you with a smooth-to-touch surface.

What grit sandpaper for painting wood?

When painting wood, use a grit that is 120 and then follow up with 150.  This will give you a good surface to paint on, without making the final product rough. You can always start with a coarser grit and then move to a finer one, but generally, these two are great.

What grit sandpaper for painted wood

The recommended sandpaper for painted wood is 150 grit sandpaper. This will help remove any scratches or imperfections in the paint and give the surface a smooth finish. Be sure to sand in the same direction as the wood grain, and use minimum pressure, as this can cause damage to the paint.

Best grit sandpaper for paint prep

The best grit sandpaper for paint preparation is 180-220 grit. This grit sandpaper will help remove the existing surface finish and create a rough surface for the new paint to adhere to. Make sure not to use anything too coarse, or you’ll damage the paintable surface.

Best sandpaper for painting

Finer grit sandpaper is best for painting. This ranges from 180 to 220 grit sandpaper. It creates a smooth surface for the paint to adhere to. Plus, sanding with a finer grit paper also helps to reduce the visibility of any imperfections on the surface.

What grit sandpaper for walls before painting

Use 100 to 150 grit sandpaper to sand walls before painting. This will help to remove any dirt or debris, and will also help to create a smooth surface for the paint to adhere to. Use a light touch when sanding, as you don’t want to damage the surface of the wall.

What grit sandpaper to scuff paint to repaint

220 grit sandpaper is perfect if you’re scuffing paint to repaint.  This type of sandpaper will quickly and effectively rough up the paint surface, making it easier for the new paint to adhere. Since you are repainting, the surface only needs light sanding for the new paint to grip.

Conclusion

So, what grit sandpaper for wood before painting? The bottom line is that no two kinds of sandpaper are entirely the same, so you want to know what it is made of and the grit size before using it on your wood, especially before painting it.

So if you want that flawless finish and good paint adhesion after applying paint to your wood, make sure to use the right grit sandpaper, and you will have yourself to thank for it.

Additional Resources

How to Sand without a Sandpaper.

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