Profile sanders are a fairly recent invention and are all the more appreciated for that reason. Profile sanders can be used for sanding in tight corners, or along grooves or ruts. A good profile sander comes with an assortment of different sanding shapes -- known as profiles -- that can be attached, not just the standard triangular profile.
The available profiles can be classed in three categories: convex, concave and angled profiles. As the name suggests concave profiles are used to sand concave surfaces. Angled profiles are available in a number of different angles (typically 30, 45, 60 and 90 degree angles) and are used for sanding the bottom and sides of slots or grooves.
When purchasing a sander consider the following:
Operation of the profile sander is the same as for a standard finishing sander. The obvious difference is that you must select the correct profile bit prior to its operation.
The normal weight of the sander is sufficient to sand and there is no need to exert extra pressure. Contrary to popular belief, additional pressure is detrimental to efficient sanding as it slows the speed of the pad.
Finishing sanders cause thousands of small abrasive grits to move against the wood at a high speed. Each grain moves in the same direction at a constant speed, ensuring that the cutting action is uniform over the whole area.
Begin the sanding process with a relatively coarse paper (the coarseness will depend on how much sanding there is to do) and then move down to finer paper. Do not jump from a coarse paper straight to a fine one, but step through the various grades. Too great a step will mean that you cannot sand out the "swirls" caused by the coarser paper.
Successful sanding is a result of patience and perseverance. The more time you spend on this step, the happier you will be with the final result.