Sanding and Preparing Wood Before Staining
A little basic knowledge of sanding and preparing wood before staining will help your staining project go faster and easier.
Sandpaper or Power Tools
The grade, or grit, of sandpaper is based on the number of sand granules per square inch of paper. The higher the number, the finer the grade. Lower-numbered grades denote coarser sandpaper. The grit numbe is generally printed on the back of each sheet.
Medium and fine grades of sandpaper are generally used in refinishing furniture and antiques. Coarse grits (those under #100) damage a fine wood finish. Medium grits, such as #120 and #150, are useful for removing old finish or scratches. Fine grits, such as #220, are frequently used for a final light sanding just before applying stain to the wood.
Power tools make sanding go faster, but heavy-duty ones such as belt sanders are designed for heavier carpentry work and could quickly ruin a fine antique. A palm sander, a lightweight rotary sander, is more suitable for refinishing.
Hand-sanding is preferable for fine finishes and delicate pieces. Tear sandpaper sheets into fourths, then fold them into pieces just big enough to hold with three fingers. You can create a makeshift sanding aid by wrapping a piece of sandpaper around a block of wood that fits in your hand. Better still, use a contoured sanding block, available at hardware stores, that allows you to attach sandpaper by inserting the ends into grooves at either end of the block.
Sand with the Grain
Close inspection of a piece of wood reveals pores in the surface that form a pattern called the grain. Always sand in the direction of the grain--never perpendicular to it or at an angle. This also applies when working on edges and hard-to-reach corners. Scratches made by sanding against the grain will look unattractive on the finished piece and will be particularly noticeable after staining.
Position the piece so that the surface being sanded is horizontal and at a comfortable height. For a clean finish, hold the sanding block flat, firmly applying even pressure while moving back and forth in the same direction as the grain. Exerting excessive pressure or using the corners of the sanding block will create unwanted depressions in the wood.
The same rules apply when you're using a palm sander: sand with the grain and hold the sander flat against the wood while applying even pressure.
Removing the Dust
Wood dust from sanding will cause problems if it's not removed from the surface before staining. Dry rags or brushes aren't the most effective tools for removing dust. Instead, use a tack cloth, a sticky piece of cheesecloth made especially for this purpose. Wipe the folded tack cloth across the wood to remove dust. As each side becomes saturated with dust, refold the cloth to expose a fresh surface. Inexpensive tack cloths are available at hardware stores, or you can make your own by soaking a 12" piece of cheesecloth in a small amount of tung oil. Store tack cloths in a sealed plastic bag to prevent them from drying out between uses.
Some of the wood dust from sanding will become airborne, so it's wise to wear a particle mask while working.