Sandpaper might seem like one of those straight forward things – it makes things smooth. You know there are coarse ones and soft ones, but did you know there is a lot more to it than just that?
Types of Sandpaper
- Garnet Minerals: The only natural abrasive, garnet produces the smoothest, most even finish. It wears out the fastest though, so stock up. Ex. wood working especially for the last pass.
- Aluminum Oxide: Last longer than the others because it contains a self renewing property (who knew!), but is more delicate and can crumble easily. Used for quick removal and smoothing.This is your most typical kind of sanding paper.Ex. sanding sponges and flat papers.
- Silicon Carbide: Clog-free smoothing of joint compound. Also ideal for harder materials such as metals and plastics. Ex. sanding screens for drywall.
- Ceramic Aluminum Oxide: The addition of ceramic grains makes for a stronger and rougher sandpaper. Ceramic is the most expensive. Ex. sanding discs and belts. Typically used with sanding machines.
Keywords to Know
Grit: refers to the number of particles per square inch. This is an important number, especially when a project calls for a specific grit #.
Grit Sanding Sequence: Grit sequences are often called for when doing certain home improvement projects such as refinishing floor and furniture. A sequence might be: 36, 60, 80 or 36, 50, 80 (coarse, medium, fine). As you will start to notice, the sequence always starts with the roughest paper first moving up to the finest last. We will go into detail below.
Sandpaper Grit Categories
- Extra Fine: 240-600. Used between coats of paints and varnishes, such as polyurethane finishes for floors.
- Fine: 120-220. Used for final sanding phase in most projects. Leaves you with a smooth finish.
- Medium: 60-100. Used for general sanding before the final sanding phase.
- Coarse: 40-50. Used to remove previous finishes.
- Extra coarse: up to 36. Used for the hardest to remove paint and varnishes. Most common use is floor sanding.
Is there a big different between grits in the same category such as 80 vs 100 grit?
Each Grit Number Does Make a Difference
Surprisingly, you have to pay attention to this. Grit affects absorbency when staining and varnishing. When sanding multiples of something, make sure to finish on the same grit # if you plan on staining or varnishing. A wood sanded with a 80 grit paper will absorb stain much differently than a 100 grit paper. Why? The finer the grit you end with the smaller the exposed wood pores become. Not convinced since you can’t see these teeny, tiny pores? Just trust us.
With Which Grit Should I Start With When Removing Finishes?
Rule of thumb with any sanding project is to start with the least coarsest grit possible. It’s truly a trial and error to begin with. You don’t want to sand your item down to the bones. Do not jump grit categories, such as coarse to fine. You might be tempted to save time, but your stain and/or varnish will not go on properly.