12th in a series of articles by Barb Siddiqui

There are any number of power tools for sanding jobs: hand-held belt sanders, wide-belt sanding machines, oscillating drum sanders and stationary disc sanders. The most common is the palm-grip random orbit sander, a real convenience for a small workshop. The best advice for using this tool is don't apply unneeded pressure to the job. Instead, allow the eccentric rotation of the pad to do the work, and apply light, even pressure all across the surface to be sanded.

Hand sanding before finishing a project is probably the least-liked chore in woodworking, but doing this job poorly is a sure way to ruin what may have taken days or weeks to build. A couple of basic rules to remember are: it is best to sand with the grain, not across it, and also to think of sanding in at least three steps of grits, not two. Since each individual grade of sandpaper is meant to eliminate the scratches of the coarser grit used before it, skipping from coarse to fine grits, without an intermediate sanding, will most likely leave unsightly scratches under your final top coat. So, no matter what grit size you decide to start with, plan on advancing through by three grits, coarse to fine.

There is a bewildering variety of sandpaper products available. Aluminum oxide is the most economical, and is good for raw wood. Open coat sandpapers mean there are open spaces between the grit particles, which help prevent the sandpaper from clogging with dust and losing its effectiveness. Open coat papers are a necessity on softwoods and on any wood that may have a resin build-up.

Closed coat papers have fewer spaces between the grit particles. They cut faster and smoother, but may clog up quickly with sanding dust. These papers are best used for final light sanding of non-resinous woods, and for use between coats of applied finish. "Wet/dry" sandpapers, usually silicon/carbide, are made to work with a lubricant such as water or kerosene, and are excellent for use with finishes, or on metal.

It's best to buy a variety of sandpapers and experiment with them for the work you do. Store them flat and protect them from moisture. While you're at the hardware store, purchase a "tack cloth" to wipe sawdust off your project between sanding grits.
Sanding blocks can be anything, from a short piece of 2x4 lined with cork to an ergonomically-designed walnut block with spring-loaded attachments for the sandpaper. When you've decided on the size block you will commonly use, it is helpful to measure its width, then attach an old hacksaw blade to a piece of plywood, exactly that width from the edge of the wood. Set a slim washer under each end of the blade to elevate it slightly, and screw it down through the end holes of the blade. This way you have a cutter already sized to quickly make strips for your sanding block out of a full-sized sheet of paper.

Before you sand, glue joints should be carefully scraped. It is best to sand and finish any parts you can before assembly, being careful to not get any finish on areas to be glued. Doing so will affect the glue bond, which needs bare wood.

Sanding irregular surfaces can be downright vexing. Curved moldings, inset corners, thin spindles and deep grooves all present special needs when preparing a piece for finishing. Many of these are cases that go by the old rule: "whatever works."

Wrapping sandpaper around a dowel works for many concave spaces. If you take time to cut and glue different grits to 1/2", 3/4" or 1" dowels, you'll be surprised how often you reach for them. A piece of 1/4" square trim molding, wrapped and glued with sandpaper, works well to take off those whiskers and rough surfaces in dadoes or grooves, and along the edges of a rabbet cut. A piece of quarter-round molding, covered in the same way with sandpaper, will give you a half-round and two sharp edges for sanding in V-groove spaces. Common fingernail files are sandpaper and can be very handy for getting into tight spaces.

For complicated pattern moldings, a piece of packing Styrofoam can be shaped with scrapers to match the profile needed, then covered with sandpaper to smooth the finished product. For very small piecework, glue different grits of paper on each side of a 3"x 7" piece of 1/4" ply and move the workpiece over the paper, rather than the paper over the piece. This board is also useful for chamfering the ends of dowels.

One useful aid is made by tracing the outline of a large C-clamp onto plywood, cutting it out and tacking a 1" strip of sanding belt to each end with a little flex left in it. This gives you a bow-shaped handle to allow the belt to round over edges of different dimensions, or take off a corner when you need to.

For sanding square edges, cut a wood block about 4"x7", then glue a 2" x 7" piece of one grit of sandpaper on half of it, 2"x7", and another 2" x 7" piece of finer grit of sand paper on the other half. Glue and screw an upright divider about 3" high in the center, being careful to set it accurately perpendicular to the sandpaper base. The upright will serve as a 90-degree fence to hold against the workpiece, allowing you to sand an edge square to its face, and gives you a choice of two grits to use, depending on what needs to be done with the edge.

Spindles in an assembled workpiece can be sanded using a long 1" strip, simply pulling the ends back and forth around them like a shoeshine cloth. Any piece of sandpaper, whether you use it alone or secured to a block, will benefit by lining its edges with common masking tape on the back side to make it more tear-resistant.

Sandpaper can also be cleaned, so don't be too quick to discard it. If it loads up with dust, use a stiff brush to clear it, or get a 'File Card' with short metal bristles to clean it off. Aluminum oxide papers have particles that will fracture as it is used, creating new, sharp edges. If cleaned up, it can then be used as a finer grit of sandpaper.

After sanding your workpiece through several grits, take a moment to pass your fingers over the work. It's amazing how much you can detect with your fingertips. It also helps to hold a strong worklight down low at the edge of a workpiece, then bend down and sight across the surface of the wood. Light and shadow will show up any indentations or irregularities in short order.

Taking your time at this stage of a project often means the difference between turning out a piece of woodworking that looks amateurish or one that looks quite professional. It's my goal to strive to do the very best I am able. And then the next time, to do it even better!