Sanding is the necessary evil that comes near the end of just about every woodworking project. If you're like me, this is where your motivation starts to drag. But it's while you're sanding that a project really comes alive, showing off the beauty of the wood. And a good sanding job is also the key to adding the perfect finish to your project.
This is where the right power sander comes in, delivering great results in a short amount of time. From belt sanders for the rough work to random-orbit, finish, and detail sanders designed to fit into the tightest spaces, there's one for just about every smoothing and finishing task.
So, it's usually just a matter of matching the right tool to the job. And while operating these sanders doesn't involve a steep learning curve, there are still a few things to keep in mind when using each of the different types. Here are some simple techniques that will help you get a smooth surface, ready for a finish in no time.
Some woodworkers might argue that a belt sander isn't a tool often associated with fine craftsmanship. But the belt sander is a great choice for a number of everyday woodworking tasks. In fact, by using the proper techniques, a belt sander can save time and produce a dead flat surface.
Of course, belt sanders can hog off wood at a surprising rate, so they're not for use on delicate plywood veneers. But when it comes to leveling a glued-up panel that won't fit through your planer, a belt sander may be the best solution. It may not be the tool for a final finish, but it should still be a part of your sanding arsenal.
A QUICK CHECKUP. Before you can get good results with a belt sander, it's worth taking a few minutes to inspect the tool. The most important thing to look for here is the flatness of the platen (the thin metal plate under the belt). If it's bent, dented, or damaged, the sander won't leave a flat surface
and it may have a tendency to dig into the wood. The good news is that the platen is fairly easy to replace (your owner's manual will show you how). Other than that, you just need to make sure the belt is tightened and tracking properly before getting started.
SCRAPE FIRST. With your sander tuned up, you're almost ready to get started. But first it's a good idea to scrape off the glue squeezeout from the joints. The hardened beads of glue often have a soft center that will gum up your sandpaper in a hurry. A scraper does a great job of removing the squeezeout.
INITIAL FLATTENING. When that's done, I draw some pencil marks on the surface to help measure the progress. Then, I start with an 80-grit belt for most panels. This aggressive grit cuts quickly and makes short work of leveling the surface.
For these first few passes, you'll just want to keep the sander moving to avoid gouging the workpiece. Sanding across the grain will get rid of ridges and erase the pencil marks. Then, a couple of diagonal passes with a 100-grit belt levels the panel. By this point, it should feel flat to the touch, but you'll need to mark it to make sure.
CHECK YOUR PROGRESS. One way to do this is to use a straightedge and mark the low spots with a pencil. Step 5, at right, shows you what I mean. Then it's just a matter of sanding down the high spots until the panel is level.
Finish with the belt sander by making a final pass using a 120-grit belt and moving the sander with the grain. This removes the marks left by the previous grits and prepares the surface for further smoothing with a random-orbit sander.
Pull the scraper along the joint to remove glue -
Make light pencil marks across the width of the panel
Scrape First. Use a scraper to remove the beads of dried glue that have squeezed out of the joints during assembly.
Draw Reference Lines. Pencil lines across the panel allow you to see high spots and low spots as you sand.
Keep the sander moving perpendicular to the grain
\ Work diagonally to flatten the panel
Sand Cross-Grain. With an 80-grit belt installed, move the sander across the grain to level the surface of the panel.
Sand Diagonally. Switch to a 100-grit belt and move the sander at an angle to the grain, alternating directions.
Mark low spots
Make final pass with the grain
Check Your Work. Lay a long straightedge across the width of the panel to identify and mark any remaining low spots.
Sand With the Grain. Finish by sanding with the grain to remove cross-grain scratches using a 120-grit belt.
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