Random-orbit sandcrs arc aggressive enough for heavy-
duty jobs, yet they have the finesse for finish work, even Finish faster. Random-orbit sanders work well for flat and contour sanding and leave a virtually scratch-free surface.
on delicate veneered surfaces. _
according to the diameter o! the abrasive disc they use. There arc 4,/2-in., 5-in., and 6-in models.
Like the angle grinders which Ihey resemble, right-angle random-orbit sanders are designed tor heavy-duty and continuous use. This sander category is the most power-till, and also the loudest and the most prone to vibration.
As shown in the photo at left, the motor is offset trorn the sanding pad, and there's a handle that extends from the motor housing. With this configuration, the right-angle sander isn't as well balanced as other types. It takes two hands to use this tool, and a dust-collection hookup is a necessity.
On this type of sander, the motor is positioned direc tly above the sanding pad, and there are usually two h.indles.
FEATURES to consider
It you plan on doing a lot of sanding on large, flat surfaces, consider purchasing a 6-in. sander—one that takes 6-in.-dia. discs. For general-purpose sanding, 5-in. discs are the most convenient to use, and they are also the most commonly available.
Right-angle and palm-grip sanders are available in both electric and pneumatic (air-powered) models. (See top photo, right.) In general, pneumatic sanders run more smoothly than their electric counterparts, and they also tend to sand more aggressively. However, pneumatic sanders require a big (5-HP or larger) air compressor to run efficiently.
Variable speed control allows you to slow down the sander's rpm for delicate work like buffing, polishing, or sanding lightly between finish coats. Variable speed control is also useful when sanding contours, edges and metal. On some models, there's a speed control dial, separate from the trigger switch. This feature makes it possible to change speed while sanding.
Pressure-sensitive adhesive (PSA) vs. hook-and-loop discs
Some random-orbit sanders are designed to use pressure-sensitive, adhesive-backed (PSA-type) discs, while others take hook-and-loop discs. Though they're more expensive than the PSA variety, hook-and-loop discs can be removed and reused many times. Hook-and-loop discs also make it easy to switch grits.
Setting a spinning pad on your workpiece can create swirl marks or even gouge the surface. A brake keeps the pad from freewheeling too quickly.
If you own a large air compressor, consider buying a pneumatic sander. These air-powered models are more compact and sand more aggressively than their electrically powered cousins.
Discs, pads and dust extraction. On some sanders, dust is extracted via holes in the abrasive discs. Accessory pads let you use your sander for buffing and polishing. The plastic dust skirt fits around the sander to promote dust collection. For optimum dust control, connect your sander to a shop vacuum with a flexible hose.
OPTIONS worth having
These well-balanced units are designed so th.it you can use them with one or two hands. Beefier in-line models approach right-angle sanders in power; lightweight models can fall into the palm-grip league. Overall, their combination of power, balance and smooth operation makes in-line sanders the most versatile of the three random-orbit sander types.
This type of sander is essentially an in-line sander without tho handles. These compact models provide moderate power and excellent balance for light-duty use.
Replacement backing pads.
For sanding contoured parts, you'll want to use a soft backing pad.
Abrasive and polishing pads. Use woven abrasive discs for sanding between coats of finish. Sponge pads are available for polishing.
Suction hood and vacuum hose. Adding a suction hood will increase your sander's dust-collection efficiency. For dust control during heavy-duty sanding, use a vacuum hose to connect your sander to a central dust collector or shop vacuum.
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