So your project is assembled; now what? Before you move on to painting or staining, you are going to need to sand your project to get the best results.
Love it or hate it, it really is one of the most critical steps in woodworking. It is often rushed or even skipped, which can severely impact the look and finish on your project, and ruin all that hard work! If you are at this point but are tempted to skip straight to staining, please don’t. Read through this handy guide I have put together, and take your project to the next level to make it look great!
Understanding Sandpaper Grit
The most relevant thing when selecting sandpaper, is what grit the sandpaper is. So what is sandpaper grit?
Sandpaper Grit Definition
Sandpaper grit refers to the size of the abrasive particles on the papers. The grit number will tell how course of fine the sandpaper is. A lower number refers to a more coarse grit where as a higher number refers to a more fine grit.
Let’s dive into some common sandpaper grit numbers you are likely to come across when woodworking and the best time to utilize them.
Coarse Grit (40-60)
- What it’s for: Coarse grit sandpaper can be used for heavy removal of wood. It can make quick work for shaping or smoothing out deep imperfections. Care should be used when using coarse grit sandpaper, as it can remove too much wood too quickly and have a negative impact on your workpiece.
- When to use: If the wood has a rough surface or if you are needing to remove old paint or varnish, coarse grit sandpaper can be useful.
Medium Grit (80 – 120)
- What it’s for: Medium grit is great for general sanding and is usually the starting place for most preparation of wood for staining/finishing. It won’t be nearly as aggressive as coarse grit, but is still rough enough to get the wood smoother without too much effort.
- When to use: Use this grit when beginning to prep wood for fine grit sanding for staining. It is also useful for doing some light shaping and is an all around good sandpaper grit to go for.
Fine Grit (150 – 180)
- What it’s for: A fine grit sandpaper is used as a finishing sandpaper. It gives wood a very smooth feel and makes it look great. It is also useful for small detail items, where a more coarse grit sandpaper risks taking too much material off.
- When to use: Fine grit sandpaper is usually the last sandpaper used before finishing the workpiece with either stain or pain. I usually will sand up to a grit of 180 to prepare my project for staining. You can sand to a finer level of grit, but this is usually where most people will stop with sanding.
Extra Fine Grit (220 and above)
- What it’s for: Extra fine grit sandpaper is mainly used for smoothing the surface between layers of finish, such as varnish, shellac, or polyurethane. It creates an ultra-smooth finish and is often used in the final stages of a project.
- When to use: Use extra fine grit after the last coat of finish for an incredibly smooth, polished look.
Common Sandpaper Guideline
The common way to use sandpaper, is to start with either a coarse or medium grit sandpaper (depending on how rough the workpiece is initially) and work your way up to a fine grit sandpaper. If you try to start with a fine grit, it will take a much longer time to get the workpiece smooth.
Types of Sandpaper Materials
Now that you have a good handle on the different grit numbers and what they mean, the secondary item to look at is your sandpaper material.
You can use the list below for a quick reference on some of the different sandpaper materials and uses. I usually use aluminum oxide because it is so readily available but I don’t focus on the material as much as I do the grit number.
| Material Type | Best for | Durability | Common Uses |
|---|---|---|---|
| Aluminum Oxide | General-purpose sanding | Good | Wood, metal, and plastic. Most common sandpaper. |
| Silicon Carbide | Wet sanding and finishing | Better | Wood, metal, and plastics. Can be used in wet sanding applications. |
| Garnet | Fine woodworking | Poor | Woodworking. It can provide a high-quality, smooth finish. |
| Ceramic | Heavy-duty material removal | Best | Can be used for aggressive material removal of wood or metal. |
Choosing the Right Sandpaper for Your Project
Depending on the project at hand, you will want to choose the appropriate grit and material of sandpaper. The guidelines below does not have to be followed exactly, and with some experience you will become more comfortable in choosing the correct sandpaper for your job and following your best judgement. These are just general rules to get you started.
- Preparing Rough Wood
- Recommended Grit: In the beginning stages of preparing wood or in an attempt to remove large amounts quickly, a coarse grit (40-60) will work best.
- Smoothing Bare Wood
- Recommended Grit: Once the wood is to the desired shape, you can start focusing on smoothing the surface. This is where you will want to move up to a medium grit (80-120).
- Finishing Wood
- Recommended Grit: For most of your projects, you will find after using a fine grit (150-180), your project will be smooth enough for staining or painting. This is as smooth as you will need to go on *most* of your projects, however there are exceptions.
- Sanding Between Coats of Finish
- Recommended Grit: If you would like to sand between coats of paint, varnish, or polyurethane to help remove imperfections and bits of dust, you would use a fine grit (220 and above).
Pro Tips for Effective Sanding
- Sand with the Grain
- Always sand in the direction of the wood grain to avoid scratches that are difficult to remove later. Sanding against the grain can leave marks that become visible after finishing.
- Use a Sanding Block or Orbital Sander
- Using a sanding block ensures even pressure across the surface, reducing the risk of gouging the wood. An orbital sander is ideal for larger surfaces and offers consistent sanding results. Just be careful, as power tools can be very helpful but can also be catastrophic to your project you have worked hard on.
- Don’t Skip Grits
- To achieve a smooth finish, avoid jumping from a coarse grit directly to a fine grit. Progress through the grits (e.g., 60 → 120 → 180) to ensure each step refines the surface.
- Clean the Surface Between Sanding Steps
- Dust and debris left behind from sanding can clog the sandpaper and reduce its effectiveness. Use a vacuum or tack cloth to clean the surface before moving to the next grit.
- Replace Worn Sandpaper
- Worn-out sandpaper doesn’t sand effectively and can burnish the wood, making it harder to stain. Replace sandpaper as soon as you notice it becoming less effective.
- Start with a Fine Grit if Unsure
- If you are not sure what grit you should be using, error on the side of too fine a grit. If you need to go more coarse with the grit, it easier than starting with a coarse grit and wishing you hadn’t.
Conclusion
Choosing the right sandpaper for your woodworking projects can make a big difference in the quality of your work. Understanding grit, material types, and proper sanding techniques will help you achieve smoother, more professional results. .By selecting the correct sandpaper for each stage of your project—whether you’re prepping rough wood, sanding between coats of finish, or applying the final touches—you’ll save time and effort while producing top-quality results. If at first it seems a bit overwhelming, just take a step back and give it your best try, because that is the best way to learn. Happy sanding!
