Most woodworkers think of sanding as the drudgery part of the project. It may not be the most enjoyable part, but everyone wants the best possible finish after all the hard work that has gone into creating the piece. How the material is finished has as much or more to do with sanding than the actual finish used.
Sanding by Hand:
There is a reason for each step when sanding. These steps will help you to achieve the end result of the finish you want to achieve.
Step 1: The removal of saw and/or tool marks is the primary goal of this step. Start with a flat, level surface to work with. Using a relatively rough 80 to 100 grit aluminum oxide sandpaper and sanding opposite corner to opposite corner until both tool and saw marks are gone and the surface is flat. This will achieve the first step. Stop here and move on to the next step.
Step 2: The only goal of this step is to eliminate the scratches left by previous step. Using 100 to 150 grit aluminum oxide sandpaper, begin sanding in the opposite direction that you used in the previous step. When the marks left by Step 1 are gone, you have completed this step.
Step 3: In this step, you are repeating Step 2, but now you will use 180 grip aluminum oxide sandpaper. Work with this until the marks of the previous step are gone.
Step 4: The last step is done to smooth out all remaining scratches. Switch to Red Garnet sandpaper at 180 grit. Sand with the grain until the smoothness you want is achieved.
In a few cases, such as some hardwoods, it may be necessary to do one more step with a Red Garnet 220 to 320 grit to achieve optimal smoothness.
Using Power Sanders:
Sanding with Machines is obviously much faster and easier than sanding by hand. Unfortunately, faster may mean deeper scratches, so make sure to let the machine do the work. The harder you push down on the sander, the deeper the scratches, therefore, the more time it will take you to get the scratches out, so once again, make sure you let the machine do the work!
When using the power sander, you will follow the same Steps as in the Hand Sanding above. Be sure to use open face paper if available and take your time. Vibrating sanders work best when you work slowly.
If you follow these suggestions, the "drudgery" of sanding will go faster and the outcome will surely be more satisfying.