Sometimes Different Results with The Same Tools-in Different Woods

Subtle Differences So smooth is both visual and tactile, looking and feeling differently in different places, with different results from different tools, and sometimes different results with the same tools—in different woods. How do we use that information effectively? I have come to a number of conclusions through my experience working with planes. For one, removing a lot of wood by sanding is, in most situations, a poor and inefficient choice. Bring wood as closely as possible to its final shape and finish with a cutting edge—a plane, scraper, or power tool. After grinding the work with abrasives, sanding with succeeding grits to eliminate the deep scratches from the coarse shaping grit is expensive and time-consuming, and raises excessive fine dust. Sandpaper’s first use was as a final step in polishing the work, and at its most aggressive, removing minor tool marks. I think that remains its best use. Another important point: Wood shaped by abrasives, rather than by a cutting edge, results in both the shape and surface being different. The differences are subtle, but important. The cut pieces reflect the crispness of the edge used to shape them, and the sweep of the stroke the artisan used to make the cut. Sanded pieces feel and look ground down, reflecting the back-and-forth scrubbing or rotary movement of the abrasives used. The artisan must be aware of the differences and how they will affect the final product. In summary, on a piece where you want to bring out the figure and texture (grain) of the wood—a piece that is to have no finish or only a light finish such as linseed, lemon, or tung oil, wax, or shellac—smoothing with a clean-cutting plane gives spectacular results and brings out the beauty of the wood. With some difficult-to-plane woods, however, taking the surface all the way down to a polish with a plane can be demanding and not necessarily efficient. On some special pieces, the extra effort may be worth it. That is an individual decision. For most work, however, leveling with a plane, smoothing (if required) with a scraper, and a final polishing with sandpaper will be the most efficient procedure. This technique is especially applicable if a heavy surface finish, such as lacquer, brushed varnish, or a catalyzed finish, is to be applied. The Challenge of Sandpaper Grit The grit size on sandpaper refers to the maximum size contained. On most papers, up to 65% of the abrasive is smaller than the listed grit size, some quite a bit smaller. This means the scratch pattern will be inconsistent, with the listed grit size making deeper scratches than the remaining abrasive. This inconsistent scratch pattern will then have to be reduced by the inconsistent scratch pattern of the next finer grit, and so forth, until the scratch pattern is fine enough not to be easily discerned by the eye or hand. That is why you should not skip grades when sanding. Some of the new premium papers have a more consistent grit size with as much as 95% of the abrasive being of the listed size, so attaining good results should be easier. Source: Motherearthnews