Everyone knows that sanding is the best part of woodworking. I bet every time you tackle a project, you just can’t wait to grab that sander. Since it is so much fun you probably don’t care if it takes extra time, but there are ways to be more efficient.
The objective is to remove any flaws in your project like dents or scratches by sanding with a grit course enough to remove the problems quickly. Then you can work your way up through successively higher grits to make the surface really smooth.
The secret is picking the right starting point. Don’t begin with too coarse a grit because it will make you work harder than necessary sanding out the scratches. Sandpaper always leaves scratches, even when you sand carefully with the grain. But as you move up to successively higher grits the scratches will get smaller. After you’ve smoothed out the flaws with your first sanding grit, every grit you use after that is just removing the scratches left by the previous grits.
If the first grit you choose is too fine and won’t clean up the surface, you can always drop back down a level or two and then work your way back up.
Be sure to progress up through every grit level; 60, 80, 100, 120, 150, 180, 220 and on. Typically you will want to stop at 180 or 220 if you are planning to stain the wood. Higher grits will close the pores of the wood and make it difficult for stain to penetrate.
Go with the grain. Sanding cross-grain tears the wood fibers so sanding scratches show up more, especially on stained wood. If you sand with the grain, scratches are disguised by the grain texture. Always use a flat block to back the sandpaper when sanding by hand. Using your hand to back the sandpaper can hollow out the softer, early-wood grain leaving ripples. If you use a power sander, move the sander slowly over the surface of the wood in a pattern that covers all areas approximately equally.
Use long, even strokes. Don’t press hard; too much pressure can cause gouging at the edge of the sanding block. Change the sandpaper as soon as it clogs or wears smooth. Between sandings, brush off and vacuum up all sanding debris, and then wipe with a tack cloth. Sawdust or grit caught under the paper can leave unwanted scratches.
To know when you are done sanding, look at the wood in a low-angle reflected light. Or wet the wood then look at it from different angles. Before you apply your finish, raise the grain by wiping the surface with water. Then sand lightly to remove the nubs from the raised grain.
Always, always use dust collection. Sawdust can ruin your finish and worse, it’s dangerous for your lungs.
Sanding demands time and attention. The care you put into sanding will determine the quality of the finish and the beauty of your finished project.