I’ll never forget the time I ruined a beautiful oak tabletop because I used the wrong sandpaper grit. It was like I’d created a topographical map instead of a smooth surface! That experience taught me a valuable lesson: choosing the right sandpaper grit is crucial for achieving that perfect finish we all strive for.
Did you know that sandpaper grits can range from as coarse as 24 to as fine as 7000? That’s right, folks! With such a wide range, it’s no wonder many woodworkers feel overwhelmed when standing in front of the sandpaper aisle. But fear not! In this guide, we’ll demystify the world of sandpaper grits and help you choose the perfect abrasive for your project.
Understanding Sandpaper Grit Numbers
Before we get into specific uses, let’s break down what those numbers on sandpaper actually mean:
- Grit numbers indicate the number of abrasive particles per square inch of sandpaper.
- The higher the number, the finer the grit and the smoother the finish.
- Grits are typically categorized as coarse, medium, fine, and extra-fine.
Here’s a quick breakdown:
- Coarse: 40-80 grit
- Medium: 100-150 grit
- Fine: 180-220 grit
- Extra-fine: 320 and above
Pro tip: Always progress through the grits in order. Skipping grits can leave deeper scratches that are hard to remove later.
Coarse Grits (40-80): The Heavy Lifters
Let’s start with the rough stuff:
40-60 Grit:
- Use for heavy stock removal and stripping old finishes.
- Great for flattening warped boards or removing deep scratches.
- I once used 40 grit to level out a badly cupped piece of walnut – it was like magic!
80 Grit:
- Ideal for initial sanding of rough lumber.
- Use after 60 grit to remove deep scratches.
- Perfect for shaping wood, especially on a belt sander.
A word of caution: Coarse grits can quickly remove material. Always sand with the grain to avoid deep cross-grain scratches.
Medium Grits (100-150): Smoothing Things Out
Now we’re getting somewhere:
100-120 Grit:
- Great for removing minor imperfections and smoothing surfaces.
- Use after coarse grits to remove scratch marks.
- I always use 120 grit before applying stain – it opens up the wood pores just right.
150 Grit:
- Excellent for final sanding before applying finish on softwoods.
- Use on hardwoods before moving to finer grits.
- Perfect for scuff-sanding between coats of finish.
Pro tip: If you’re painting your project, you can often stop at 150 grit. Paint doesn’t require an ultra-smooth surface to adhere well.
Fine Grits (180-220): Prepping for Finish
This is where your project really starts to shine:
180 Grit:
- Ideal for final sanding on hardwoods before finishing.
- Use to smooth raised grain after water-based stains or sealers.
- Great for light sanding between coats of finish.
220 Grit:
- Perfect for final sanding on most hardwoods.
- Use on softwoods for an extra-smooth finish.
- I always hit my projects with 220 before applying oil finishes – it makes a world of difference!
Remember: The harder the wood, the higher the grit you can use for final sanding.
Extra-Fine Grits (320 and above): The Finishing Touch
For those glass-like finishes:
320-400 Grit:
- Use for ultra-smooth finishes on hardwoods.
- Great for sanding between coats of varnish or lacquer.
- I use 320 grit for my final sand on most hardwood projects.
600 Grit and beyond:
- Primarily used for sanding finishes, not bare wood.
- It can create a mirror-like surface on some hardwoods.
- I once sanded a maple butcher block up to 1000 grit – you could see your reflection in it!
Pro tip: For most woodworking projects, you don’t need to go beyond 320 grit. Higher grits are mainly used for finishing work.
Choosing the Right Grit Progression
Now that we know our grits, how do we use them in sequence? Here’s a typical progression:
- Start with the coarsest grit needed to remove imperfections or level the surface.
- Progress through each subsequent grit, removing the scratches left by the previous grit.
- Stop at the appropriate grit for your project and finish type.
Example progression for a hardwood table: 80 > 120 > 180 > 220
For softwoods, you might stop at 180 or 220. For hardwoods or high-gloss finishes, you might continue to 320 or higher.
Special Considerations
Different projects and woods may require different approaches:
- Plywood and veneers: Be careful with coarse grits – you can easily sand through the thin top layer.
- End grain: Typically requires sanding to a higher grit than face grain.
- Oily woods (like teak): Often benefit from a slightly coarser final grit to allow finish penetration.
Sandpaper Types: More Than Just Grit
While we’re focusing on grit, it’s worth mentioning that sandpaper comes in different types:
- Aluminum oxide: The most common, great for general woodworking.
- Silicon carbide: Excellent for sanding between finish coats.
- Garnet: Natural abrasive, less durable but creates a beautiful finish.
I keep all three types in my shop for different applications.
We’ve covered a lot of ground (or should I say, a lot of grit?). Choosing the right sandpaper grit might seem daunting at first, but with practice, it’ll become second nature. Remember, the key is to start with the appropriate coarseness for your task and work your way up to finer grits.
Don’t be afraid to experiment on scrap wood to see how different grits affect various wood species. I still do this, especially when working with a new type of wood or finish.
Sanding might not be the most glamorous part of woodworking, but it’s crucial for achieving that smooth, professional finish we all strive for. Plus, there’s something oddly satisfying about running your hand over a perfectly sanded piece of wood, don’t you think?
