What is White Corundum 220#?
White Corundum: Also known as white aluminum oxide, it is a very pure, synthetic abrasive. It’s known for being hard, sharp, and friable (meaning the grains fracture to reveal new sharp edges during use). This makes it an excellent, fast-cutting abrasive that stays sharp longer than something like garnet paper.
220 Grit (#): This refers to the particle size. 220 grit is a medium-fine abrasive. It’s not for rough shaping but for finish sanding—smoothing out the scratches from previous, coarser grits (like 80, 120, or 150) to prepare the surface for a final finish (stain, oil, varnish, etc.).
Is 220# White Corundum Good for Wood Polishing?
Yes, but with a very important distinction in terminology.
In woodworking, “polishing” often refers to the final, ultra-smooth sheen achieved with very fine abrasives (600 grit and above) or buffing compounds.
220 grit is NOT for that final polish. It is for sanding and surface preparation.
Think of it this way:
Sanding (with 220 grit): Creating a perfectly smooth, scratch-free surface on the bare wood.
Polishing: Enhancing the sheen of the applied finish (e.g., lacquer, oil) itself.
So, 220# White Corundum is excellent for the final stage of sanding bare wood before you apply any finish.
Advantages of Using White Corundum on Wood
Fast Cutting: It removes material more quickly than standard aluminum oxide sandpaper of the same grit, making your sanding process more efficient.
Durable and Long-Lasting: The grains are hard and friable, so the sandpaper doesn’t “load up” (clog with wood dust) as quickly and stays effective for longer.
Clean, Sharp Cuts: It produces a clean surface with minimal “fuzzing” on difficult woods, which is ideal for hardwoods like maple, cherry, and oak.
How to Use It Effectively: A Step-by-Step Guide
Start with a Coarser Grit: Never start sanding with 220 grit. You must progress through the grits. A typical sequence for planed or jointed wood might be:
120 grit (to remove machine marks and minor imperfections)
150 or 180 grit (to remove the scratches from the 120 grit)
220 grit (to remove the scratches from the 150/180 grit, creating a smooth surface for finishing)
Use a Sanding Block: Always use a firm, flat sanding block (or a random orbital sander) when working with flat surfaces. This prevents rounding over edges and creating an uneven surface.
Sand With the Grain: After the initial 120-grit stage, always sand in the direction of the wood grain. Sanding across or against the grain will create scratches that will be very visible once you apply a stain or finish.
Thorough Dust Removal: After sanding with 220 grit, you must remove all the dust. Use a tack cloth, a vacuum, or compressed air. Any dust left on the surface will get trapped in the finish, creating a rough texture.
Apply Your Finish: Once the wood is perfectly smooth and dust-free, you can apply your chosen stain, oil, varnish, or shellac.