Sandpaper Grit Breakdown
Starting with the wrong sandpaper grit can add hours to your woodworking project.
A grit that is too coarse may remove more material than desired and ruin the wood. And using a sanding grade that is too fine will burn time that you can’t afford to lose.
In the event that you don’t have every sheet listed on our sandpaper grit chart, that’s not the end of the world. You can substitute a similar grit level depending on the application. Just be sure to do further research to make sure that you don’t select the wrong one.
That is, some substitutions are less intuitive than others. For instance, a craftsman looking to stain a wood piece might view P240 as a suitable replacement for P220. However, the better option is actually P180 as it gives the wood grain a stronger appearance. Also, it’s worth mentioning that P240 is a bit too fine for wood stain and will hinder it ability to soak into the wood.
Applications for Each Grit Level
As you’ve already noticed, we opted for the “P” grade system since that is what we use most in our projects. It’s also the international standard for denoting the coarseness of an abrasive.
The Coarser Abrasive Grades
Grit Levels P40 & P60 – Most projects won’t need these sandpaper grades. They’re only required for cleaning up rough lumber, evening out large bumps in the wood, & removing stubborn old paints. Essentially, you’ll use these to soften anything that’s too rough for your hands to handle. Also, they can remove almost anything so don’t hesitate to jump up to the next grit.
P80 Sandpaper – This is the starting grit for most hardwoods and is a staple for every wood worker.
P80 grit is the best option for removing saw blade burns and deeper surface scratches. In the case
that you’re working with a hardwood like Poplar, you can probably jump the line to P120.
Medium Sanding Grades
P120 Sandpaper – Any wood that was too soft for P80 will start the latter at P120. We generally use this grit when first smoothing pine, redwood, & cedar. Lastly, enamel paints and polyurethane don’t require the wood to be sanded beyond P120. The only exception would be a clear satin finish, in which case you may want to eliminate any scratches left on the wood with P150 or P180.
P180 Sandpaper – If you encounter a raised wood grain fibre, P180 has your solution. Of course, you will have to refinish the wood using the original method. On a separate note, sandpaper grade P180 is a safe option for prepping latex paints.
P220 Sandpaper – For novice woodworkers, it’s time that we tell you that you have to sand with multiple grits. P220 is generally the go-to 2nd & 3rd 3rd-level abrasive for prepping wood for oil finishes. But if you’re applying a wood stain, your destination does stop here.
Finishing Sandpaper Grits
P320 Sandpaper – When sanding between coats of polyurethane, P320 will wipe off any surface inconsistencies left
from the finish. Also, wet sanding will generally use 320 as this practice requires a very fine grit as well.
P400 Sandpaper – Only oil finishes like tung oil & teak oil require the surface to be finished to this level. And it’s also not a requirement for all woodworking projects that use those types of finishes. Lastly, you can rely on P400 to smooth the top coats of polyurethane.
Grits P600 & Up – We honestly don’t have any of these in our toolbox. However, they do have their applications. P600 & P800 are good options for finishing a piece that’s about to be polished. Just be careful that you don’t damage the wood.
