Popular Mechanics (South Africa)
Hand-held sanders
The best way to get the finish you want on your woodworking project is with a sanding machine. But which one should you buy?
EVERY WOODWORKING workshop on the planet uses sanding in one form or another. Whether you get your cardio workout by hand sanding or use one or more of the wide variety of powered sanders available, sanding wood is an intrinsic part of the woodworking process.
Buying a sander can be intimidating, so this month, we’ve taken a look at the different types of hand-held sanders on the market. To keep things simple, remember that sanders fall into one of three categories: belt, orbital and random orbital sanders.
BELT SANDERS
These machines vary in size, ranging from small file-type units to small single-hand use devices, all the way up to heavy beasts that require two hands to operate. They are primarily used for the aggressive removal of stock, such as levelling or flattening large surfaces such as tabletops. Belt sanders remove a lot of wood very quickly, which means they will take a bit of practice to use successfully. These sanders also generate a lot of dust, so having a dust extraction system in place is extremely important.
Belts are generally available from 40 grit to 200 grit, with 40 grit used for seriously rough work, and 200 grit employed for fine finishing. Belts vary in width depending on the machine, but the two most common sizes are 75 mm and 110 mm.
STANDARD ORBITAL FINISHING SANDERS
These are traditionally square or rectangular machines that use ¼-sheet, 3- sheet and
1 ½-sheet paper sizes. The pad of a typical orbital finishing sander revolves in a 1.6 mm repetitive orbit at somewhere around 12 000 to 14 000 orbits per minute (opm). They use standard sheets of sandpaper that you cut or tear to size, so sanding grits are available from 40 grit to 2 000 grit.
These devices are easy to control with just one hand and are mostly quite reasonably priced. As you move the tool across a workpiece, the orbiting motion of the abrasive creates a consistent swirl pattern on the wood surface. By working through a series of finer and finer papers, the swirl patterns will supposedly blend together until they eventually disappear. Although wonderful in theory, this is not always the case in practice. The results of your efforts often appear great, until you apply your first coat of clear finish and all the swirl patterns reveal themselves. If, however, your finish is paint or something that is similarly thick, then the residual swirl patterns should not present a problem.
For any clear finish, this is not the type of sander that will give you consistently good results. Other factors to consider when using most standard orbital sanders are that you will experience hand
and arm fatigue quite quickly, and the methods of attaching the sanding sheets are, at best, irritating, and at worst, downright frustrating.
RANDOM ORBITAL FINISHING SANDERS
These sanders generally use standard 125 mm or 150 mm circular sanding discs that are pre-punched with a hole pattern to suit extraction on your specific sander. The Festool hole pattern, for example, is only available with Festool paper.
Random orbital sanders also usually feature variable speed control and the sanding discs attach easily via the hook and loop (Velcro) system. These sanders vary in price from reasonable to really expensive top-end machines.
Then, it’s extremely important to consider extraction, not only for your health, but because if all of the abraded wood particles are removed via suction, the machine does not have to cut and recut the same particulates over and over again. These particles clog most abrasive paper up quite quickly, and not having them extracted efficiently also means it takes significantly longer to achieve the results you want. A good variable-speed random orbital sander should be the essential go-to sander in every woodwork workshop.
The random orbital sander pad typically orbits at about 3.2 mm, while at the same time orbiting in a random pattern of up to 12 000 times a minute. This dual-mode action makes these sanders more efficient, blending swirl marks quickly as you work through the abrasive sequence. Sanding discs are generally available from 40 grit to 800 grit, or even higher.
In my experience, random orbital sanders can produce flawless surfaces quickly when sanding through a sequential series of abrasive discs, and very efficiently when used with extraction. With variable speed control, it is quite easy to ‘tune’ your sanding process for aggressiveness, ease of control and reduced clogging of the paper itself. If your finishes are clear oil, polish, shellac or lacquer, a random orbital finishing sander is essential.
GEAR-DRIVEN ECCENTRIC RANDOM ORBITAL SANDERS
Gear-driven orbital sanders look like orbital sanders and typically come in two pad sizes: 125 mm and 150 mm. The big difference between orbital sanders and geared orbital sanders is that in the latter, a metal gearing system forces the pad to rotate and then orbit.
These sanders have two modes of operation – heavy and light. In the heavy-geared mode, these machines are exceptionally aggressive and will remove stock very fast. In light orbital mode, they are capable of superlative fine sanding. Variable speed is generally available in both modes. If you are in the market for just one portable sander, we recommend a high-quality gear-driven type.
WHAT TO BUY FIRST?
There are a number of other formats of sanders, such as delta and dedicated shape sanders, but they all operate on pretty much the same basis as those I’ve mentioned.
My suggestion is to purchase a good-quality random orbital sander or a geared orbital sander as your first machine, followed by a belt sander if funds allow. And, if you go for the geared orbital sander, you might even find you don’t need a belt sander at all, as it can aggressively remove stock.