Blocks For Finishing

Wet sanding solution. Rubber blocks maintain their shape and firmness during wet sanding.

Flexible support. Foam packing provides good backing for sanding irregular surfaces.

Not just for sandpaper. Use a felt block to back steel wool for more consistent results.


end allows mc to sand neatly into corners and other tight spots. Ceiling tile can be easily beveled on a belt or disc sander. I also use my power sander to "dress" or restore the working faces of ceiling tile and balsa blocks after they've become dinged or worn out of true.

To sand contours and molding profiles, I need co use a harder material that can hold the shape of the curved work. Balsa wood and basswood make good contoured blocks. These woods are easy to cut on the bandsaw and shape wich a disc sander.

For sanding finishes, che righc block is even more imporcanc. Finishes cend co gum up sandpaper very quickly. For dry sanding a coac of scaler or lacqucr, I use a fclc block. For wee sanding, look for blocks that won't swell, warp or disintegrate. Surprisingly, household sponges and rubber drafting erasers work well. (See photos, above.)

The toughest finish-sanding cask is leveling a new coac of finish on an old piece of furnicurc. Old cablecops are ofccn cracked and warped, wich surfaces chac bend and cwisc well ouc of plane. To follow these irregularities carefully while still sanding the finish thoroughly, I use blocks made from 3/4-in.-thick Styrofoam™. The foam used to pack computers, stereos and other electronic equipment works great. These blocks flex and give easily but still back the paper adequately enough for accurace sanding.

Sanding blocks are not just for use with sandpaper. I also use chcm co back scccl wool when I'm rubbing ouc a sprayed lacquer finish on a cabletop. I can see a real improvement in rubbed surfaces when I give sccel wool che added concrol of a backing block insccad of simply pushing ic around wich my bare hand.

Specialty Blocks

Occasionally, I'll invest some extra time to make blocks that are a bit more elaborate. The idea behind these blocks is still the same—co do sanding righc, and do it as litcle as possible.

Sanding sticks—Sanding scicks are very handy for smooching curves and geccing inco cighc corners. (See phoco, below left.) They work much like mecal files, buc leave a smoochcr surface chac

Sanding sticks. Shop-made wooden files are great for tight curves and corners.

Form follows function. Extra foam padding makes standard-size blocks fit a variety of specialty tasks.

Shapely blocks. Elaborate blocks can be carved to fit wide moldings. Use smaller blocks for single elements.

needs only a brief hand-sanding with a finer-grit paper before it's ready for finish. To make the sticks, shape strips of wood by hand or on the belt sandcr and glue a heavyweight sandpaper to the shaped profile with contact cement. I prefer to use cloth-backed paper on my sanding sticks because it lasts longer than the paper-backed variety.

Composite blocks—Some woodworkers like to make composite sanding blocks by laminating sheet cork, leather or rubber to wooden blocks. I get similar results with less work, by simply wrapping sheet felt or thin foam around a wood block without gluing it down. The extra foam padding helps blocks conform to fit a variety of profiles. When the sanding task is done, I toss the block and the backing material into a box with my other blocks so I can combine materials as needed for other sanding tasks.

Profile blocks—For sanding delicate moldings, such as small beads and coves, the block has to fit the molding or else you'll sand out the crispness. (See bottom right photo, opposite page.) I shape the block to the reverse of the workpiecc profile using router bits or hand tools.

When I have an elaborate molding to sand, I'll often make up separate profile blocks for each element of the molding, such as the bead, cove or fillet. Then I wrap paper around the block and sand one molding clement at a time. This advantage to this method is that it keeps the details as crisp as possible. After sanding a number of different moldings in this way, you'll accumulate a versatile supply of common profile blocks to choose from.

Another way to make a sanding block that's matched to a particular contour is to use a new product called Sandform. Available from Woodworker's Supply (800-645-9292), this two-part putty preparation can be formed to fit an existing contour before it hardens into a sanding block. A

Different abrasives for different jobs. The brown-toned sandpaf>er on the left is aluminum oxide—good for rough sanding on raw wood. Stearate-coated aluminum oxide (gray) does well for final sanding on raw wood, and between finish coats. Silicon-carbide paper (black) can be used wet or dry; it's best for sanding finish.


My goal is always to sand as little as possible. I have three strategies for doing this. First, I prep my work with hand tools. The time spent using planes and scrapers is repaid in less overall sanding time. Second. I use only one or two grits per job. Third, I quit at the lowest grit level I can. Using these strategies, I can accomplish most sanding jobs with a limited selection of sandpaper.

After hand tools, I typically start with either 120- or 150-grit aluminum oxide, and finish with 220-grit paper. On scraped or planed surfaces that will receive a sprayed clear finish without stain, I sometimes stop at 180 grit. For sm(K)th sanding on bare wood, I like to use a stearate-coated aluminum-oxide "A" weight paper, such as 3M Fre-Cut™. It outperforms and outlasts common aluminum-oxide and garnet papers. Although stearated paper has caused problems with waterborne finishes in the past, I have yet to experience any problems from the stearate coating.

For finishing work, I use Fre-Cut™ paper in grits from 280 to 400, and silicon-carbide wet-or-dry paper in grits from 220 to 1,200. Since I'm primarily sanding finishing materials with these grits, the paper tends to load up more when I'm dry sanding. To keep finish from gumming up the paper, try scuffing the paper on a carpet scrap. Wet sanding doesn't load the paper up as much, so I wet sand finishes whenever possible. —W. 7". V.

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