Sandpaper & Abrasives

Use sandpaper, steel wool and sanding sponges to smooth surfaces for a pro finish

Sandpaper & Abrasives

Sanding is a crucial step in achieving a high-quality finish. While different sandpapers may look similar to one another, they are often composed of different materials, feature a wide range of grits, and are best suited to certain surfaces.

This guide will help you tell them apart and understand which grit is best for your project.

Safety: Sanding can generate quite a bit of dust, so wear safety glasses and use a dust mask or respirator. If you’re working with a power sander, wear gloves and make sure you’re not wearing loose-fitting clothing that can get caught in the machine.

Understanding Sandpaper

Ironically, sandpaper doesn’t actually contain sand. It has long since been replaced by better natural abrasives, such as garnet, and synthetic abrasives, such as aluminum oxide.

Tip: While hand-sanding will work well for a lot of jobs, some are simply too big. In those cases, consider using a power sander or belt sander. You may also want to use an orbital hand sander. Many sanders are available for rent.

The material you’re sanding will largely determine which sandpaper to use.

There are three primary characteristics that determine the effectiveness of sandpaper and when it should be used: grit, whether it has an open or closed coat, and its abrasive material.  

  • Grit is a measure of how many particles on a piece of sandpaper could pass through a filter that’s 1 square inch. The lower the grit number, the coarser the paper. Grit numbers can go as low as 12 and as high as 600, but most of the sandpaper you’ll use will run somewhere from around 30 or 40 to 220.
  • Coating indicates how dense the abrasive material is on a piece of sandpaper. Open-coated sandpaper has abrasive material covering approximately 70 percent of its surface, leaving room for sawdust to build up, which helps prevent clogging. Closed-coated sandpaper is completely covered by abrasive material.

Material Characteristics

Aluminum oxide

  • Works well for all types of sanding, especially wood and metals
  • Good for use with a power sander
  • Friable surface sharpens itself as you sand to provide longer life
  • Synthetic material that is either tan, light gray or grayish brown

Ceramic

  • Extremely hard and durable; best for rough sanding
  • Ideal for use with power sanders
  • May be more expensive
  • Synthetic material that is generally reddish-brown

Flint

  • Economical
  • Not particularly durable
  • Best for rough work on small projects
  • Beige-colored natural material that is used somewhat infrequently

Garnet

  • Excellent for hand-sanding, especially on wood
  • Coarse paper wears down to provide fine finishes
  • Features a soft grit
  • Reddish or golden brown; natural material wears somewhat quickly, though it provides a finer finish as it wears

Silicon carbide

  • Can be used on wet or dry surfaces
  • Friable surface will self-sharpen on harder materials, like metal
  • Ideal for polishing or using between coats of finish; works with metal, plastic, fiberglass and more
  • Synthetic paper that is blue-gray, black or charcoal; often features a waterproof backing

Other Abrasives

Steel wool is ideal for removing grime and sludge from a variety of surfaces. Scrapers, abrasive sponges and water stones are other options, depending on the job.  

Type Characteristics
  • Useful for removing old coatings of paint or finish on wood
  • Graded on a number scale (like sandpaper) that determines how coarse or fine it is, rated from 0000# (super fine) to 4# (very coarse)
  • Use to prepare new surfaces or between coats of paint or finish
  • Ideal for removing paint from glass, furniture and tile
  • Like sandpaper, sheets of abrasive material that are designed to fit most drywall sanding tools
  • Can attach to hand and extended pole sanders for hard-to-reach areas
  • Ideal for sanding and smoothing drywall joints, patching compounds and plaster
  • Abrasive sponges are ideal for working in corners or on oddly shaped pieces that conventional sandpaper can’t conform to
  • Allow you to apply more even pressure than you can with just your hand, resulting in a better finish

Tips & Helpful Tools

Always sand with the wood’s grain to avoid clogging pores. In most cases, you’ll need to sand multiple times, so be patient. Start with coarse paper and gradually work your way up to finer sandpaper.  

  • Coarse grits can be used to remove large imperfections while medium grits are better for small-to-moderate surface flaws. In many cases, using a fine grit around 180 or 200 will provide the final step, though you may need to touch things up with a 220 grit.
  • Be sure to clean the work surface when you change to a new grit as debris from earlier sanding can interfere with the smoothing process.
  • Higher grits may be needed when sanding brass and other metals.
  • Don’t press too hard, simply let the sandpaper’s surface do the work.

Helpful tools

Tack cloth: A sticky piece of cheesecloth that picks up dust more efficiently than wiping a wet cloth across the surface. Wet cloths can also raise the wood grain, making the surface more difficult to stain.

Zinc stearate coating: Some sandpaper features this soapy substance, which is used to prevent clogging. While it shouldn’t be used on surfaces with water-based finishes, sandpaper with this coating will require less maintenance.