Unless all traces of sawdust and sanding dust are first removed, any finish you apply—whether it is a coat of paint or stain-plus-topcoat—is doomed to be less than perfect. Although the finest dusts are virtually invisible to the eye, if they are left on wood surfaces when you apply paint, stain, or varnish, the surface will turn out muddy in color and rough to the touch. Even the most careful, precise work when building a fine woodworking project or laying a fine hardwood floor can be spoiled by a finished surface that is flawed simply because you rushed the process during the finishing stage.
For best results, follow this four-step process. Although you may think this is excessive preparation, you'll be rewarded with a beautiful, smooth wood finish that will be the envy of everyone who see the quality of your work. This process will give you the best possible results whether you are painting the wood, applying an oil finish, or staining and finishing with topcoat varnish.
Begin By Vacuuming or Blowing Off Dust
Start by blowing off the bulk of sawdust and sanding dust using an air compressor fitted with a blower nozzle. Even better than this is vacuuming every surface and crevice of your project with a shop vacuum fitted with a good quality filter designed to trap the finest of dust. While you might imagine that any vacuuming will be just fine, all too often the vacuum cleaner will exhaust dust right back into the room, where it can resettle on the wood surfaces.
Wipe With a Clean, Dry Cloth
Next, wipe down the wood surfaces with a dry, clean cloth.
A white cloth will allow you to see how much dust you are collecting as you wipe down your woodworking surface.
You are now halfway home in preparation for finishing your wood.
Use a Tack Cloth
A tack cloth is really just a piece of loosely woven cheesecloth impregnated with beeswax. When lightly wiped over wood surfaces, it miraculously picks up dust that vacuuming and dry cloths cannot remove.
Cut your tack cloth into small squares, and lightly wipe over all the wood surfaces. Inspect the tack cloth periodically to see how much dust you are collecting, and change the tack cloth whenever it gets dirty.
Using a tack cloth can also confirm that your wood surfaces have been properly sanded. If you find that the fine threads of the cloth are snagging on rough surfaces, it is a sign that you may not have been complete enough with your sanding. If you seek a perfect finish, make sure the tack cloth glides smoothly over the wood as you wipe; if not, return to the sanding stage to get it right.
Wipe With Denatured Alcohol
Many woodworkers end the wood preparation step with the tack-cloth wipe-down, but for the very best results, conclude your preparation by wiping down the surfaces with a clean cloth moistened with denatured alcohol. The denatured alcohol will help pick up even the finest dust, and since it evaporates very quickly, it will not discolor the wood in any way. It is even safe to use on projects that will be used for food, such as a cutting board or a hardwood bread tray.
After this preparation procedure is complete, it is best to move on to the painting or finishing stage as soon as possible.
Within a day or even a matter of hours, house dust can resettle on the wood and create problems for finishing.
Following this four-step process is a perfect preparation for painting, oiling, or staining your finest woodworking projects or hardwood flooring installation. After trying it once, it will become your standard procedure for all your woodworking projects.