Sanding is the key to a professional-looking finish for a wood project you plan to paint or stain. Here, you'll find the answer to what grit sandpaper you'll need for wood.
- Raw Wood: start with 80 grit for bare hardwood (ex., maple, mahogany, oak) then move to 120 grit, 150 grit, and finish with 150 or 180 grit. If you are working with softwood (ex., pine, cedar, fir), start with 120 grit which is finer then move to 150 grit and finish with 220 grit.
- Painted wood: start with 60 grit to remove old paint, then move to 80 grit, 150 grit, and finish with 220 grit.
- Final Paint: sand with 600 grit which is super fine and use a sanding block to apply even pressure.
The guide above may alter depending on some factors, such as the condition of the wood and if the project is a new piece or a restoration of an old one. Sanding them with the right grit sandpaper will give you a smooth, gleaming finish and a project you'll be proud to show to your friends. We've researched for you, so keep reading to learn more about grit sizing for wood.
Sandpaper Grit Sizes: What They Mean
Sandpaper grit sizes can be confusing for newbies who are into woodworking. From 40 to 400, how do you choose which one you should use for your project?
Here is an easy-to-understand grit guide using CAMI standards that you can refer to when you shop for sandpaper. Aside from the number, companies have added coarseness level terms that correspond to the number.
Extra course sandpaper: 24- to 36- grit
They are used for removing stubborn paint and varnish, and for sanding old floors.
Coarse sandpaper: 40- to 60- grit
They are good for shaping rough lumber and removing bumps and old finishes, such as light coatings of polyurethane.
Medium sandpaper: 80-grit
It is the standard starting grit for hardwood. It removes shallow marks and other flaws and prepares the wood for finishing.
Fine sandpaper: 100- to 120-grit
Grit 120 is the starting grit for softwood. Fine sandpaper is used for smoothing rough surfaces and removing textured paint, stains, and scratch marks from wood.
Very fine sandpaper: 150- to 240-grit
The 150- to 220- grit sandpaper is used as the last run in sanding, and sweeping away the residual wood fibers and scraps.
The 240- grit is for sanding between finishes of paints, drywalls, and wood.
Extra fine sandpaper: 320- to 400-grit
The 320- to 360-grit sandpaper is used as the first sanding before wood polishing. The 400-grit is for the final wood finishing.
Safety Tip: Always wear a mask and goggles when sanding. These will protect your lungs and eyes from the toxic dust particles that can cause respiratory ailments and eye injuries.
The National Institute for Occupational Safety & Health (NIOSH) recommends the N95 mask that filters 95% of particulate matter. Goggles with side shields are also best for doing sanding work.
What Grit Sandpaper To Remove Paint From Wood Before Repainting
If you'll be repainting over painted wood, whether it's a piece of furniture or a wall, floor, or ceiling, you will get a smooth, gleaming finish if you sand the surface before applying a new coat of paint. Here is a general guide on what grit sandpaper to use for optimum results.
For solid wood surfaces such as doors, frames, and furniture, use 60- to 80-grit (coarse to medium) sandpaper. This grit range is also used to remove oil-based paint and old primer.
For edges, fissures, and carved surfaces, use 100- to 120-grit (fine) sandpaper. Fine sandpaper is also used to take off water-based paint.
These are not hard and fast rules. Factors you should consider are the type and thickness of the paint, the state the wood is in, the finish you want, and your sanding tool.
Thick coats of paint will need coarser sandpaper while water-based paint can be removed with fine sandpaper. Low grit or coarse sandpaper may cause damage to wood if the pressure applied is too hard while starting with fine grit will take you a long time to get a smooth surface.
If you paint over old paint that has cracks, bubbles, and flaking paint, your new paint won't stick well and will peel off in a year or so.
What Grit Sandpaper To Sand Bare Wood
When sanding bare wood, start with the lower grit (coarse) sandpaper and move on to the higher grit, or fine sandpaper. It is never the other way around or you'll end up with an uneven surface and deep scratch marks on your wood.
For rough wood that has varnish or paints cleaving to it, or it's an old floor, start with 40- to 60-grit (coarse) sandpaper for heavy sanding.
Otherwise, use 80- or 100-grit for the initial sanding for most bare wood. This medium sandpaper fixes minor imperfections or shapes the wood, and gives it a flat, smooth surface.
Following the general rule, you may skip one grit and move on to the next. So if you started with the 80-grit paper, you can skip the 100-grit and move on to 120-grit. Similarly, if you used the 100-grit for the first sanding, you may skip the 120-grit and move on to the 150-grit.
If you are sanding bare softwoods like pine or alder, start with a finer grit. Sand first with the 120-grit sandpaper, then finish with the 180-grit if you are using oil-based stain, or 220-grit sandpaper for water-based stains.
What Grit Sandpaper Should You Use Between Coats Of Paint
Use 320- to 400-grit sandpaper to sand lightly between coats of paint. Very fine sandpaper won't scratch deep and will even out scratches from the coarser sandpapers.
Then, using a damp microfiber or tack cloth, rub down the whole surface including edges and nooks after each sanding to remove the dust residue. This will prep the wood for uniform paint saturation that will give a blemish-free result.
Let the coat dry before each in-between sanding. Drying time will differ depending on the humidity of your environment. Most professionals recommend a drying time of 12 to 24 hours. Generally, water-based paints and stains dry more quickly than their oil-based counterparts.
Always sand by hand when sanding between coats of paint. After the final coat has been applied, wait for it to dry thoroughly (about one month), then sand with the super fine (600-grit) sandpaper.
What Grit Sandpaper To Fix Over-sanded Wood
A common mistake of DIYers is to overdo the sanding of a woodworking project. This happens when you spot an imperfection like a scratch or discoloration. You start sanding to remove it but go too far and create a divot instead. Divots are the usual consequence of too much sanding. Fortunately, you can remedy your mistake without too much trouble.
Begin by making light pencil marks on the divot and the area around it. Then use a hand block with 180-grit sandpaper and start sanding. Follow the wood grain and use delicate strokes until the pencil marks around the gouge fade away.
Sanding will create dust; you should use a damp cloth during the process to remove the dust so you can tell if the hole has gotten smaller or leveled off.
Important Things To Remember About Sandpaper Grits
These are the general concepts to remember when buying and using sandpaper:
- The higher the grit number, the finer the grains. The lower the grit number, the coarser the grains. Grit 60 is coarse; grit 80 is medium; 220 is fine; grit 400 is very fine.
- Never skip more than one grit when sanding. For example, when starting with Grit-80 and you plan to finish at Grit-240, don't bypass the other grits in between and jump to a Grit-220. Skipping one grit size is permitted; from Grit-80 to Grit-120 and skipping Grit-100 is okay.
- When sanding, always start with coarse sandpaper (low grit,) then work up to fine sandpaper (high grit.) This is called sanding in sequence.
- Always sand the grain. That is, sand the length of the wood, not the width. When you sand in the direction of the grain, any remaining scratch will become less noticeable because it will blend with the grain.
- In the United States, the CAMI (Coated Abrasives Manufacturing Institute) measures grit size standards. In Europe, standards for grit sizing are done by FEPA (Federation of European Producers of Abrasives.) The grit size for FEPA is preceded by the letter P (P80, P220, etc.)
Knowing what grit sandpaper to use for the various conditions of the wood you will work on is a key element to achieving that flawless finish to your walls and ceilings, or restoring a period piece of furniture to its former glow.