Electric sanders are used to make the sanding job easier and faster as they can smooth large areas within minutes, a task that can take hours if done with sandpapers or elbow grease. There are various types of wood sanders available in the market and it can prove to be hard to decide which one to buy if you’re buying for the first time. To understand the types of wood sanders, you need to understand the basic motions of sanders or the principles on which different sanders work. Sanders also vary in terms of base plate shapes as some sanders have circular plates (disc and random-orbital sander), while some utilize square, triangular or rectangular plates (sheet and detail sander).
Most wood sanders are based on either one of three basic motions: orbital, belt or rotary. Orbital motion involves the movement of the sanding plate in a small circle that causes motion in each grain of the abrasive being used. Belt motion sands in one direction, so if there are any scratch marks, they’ll only be in one direction. In rotary motion, the sanding disc rotates and the center of the disc rotates slower than the edge, so this type of motion gives uneven sanding.
Random Orbital Sander
It is the most common and widely used type of sander. It is available in various base plate shapes with rectangular, round and square base plate being commonly used. Random orbital sanders are commonly used as the direction of the wood grain is not of any concern as the sanding action is completely random. A random orbital sander leaves no swirl marks and gives a fine finish as compared to other sanders. It consists of discs of various sizes and the random action of the sander ensures that no part of the disk rotates on the same path more than once during one rotation.
It is powerful, compact and extremely versatile. It may not remove wood as quickly as others such as belt or sheet sander and it’s not as easy to control as detail sander, but it gives the finest sanding action and is the most versatile sander available.
Disc sanders are mostly implemented in stationary machines. It consists of a replaceable sandpaper attached to a wheel that is operated by electricity. A disc sander exerts a downward force on the surface as compared to a belt sander that works sideways. Disc sanders can work wood, plastics, soft materials and metals as well. The workpiece is sat on an adjustable front bench. The bench’s angle can be adjusted depending on the sanding requirements, which can be fine or rough.
The disc sander utilizes the rotary motion of the sandpaper wrapped on the disc, which gives uneven sanding as compared to the orbital or belt sander. The disc sander is mostly preferred for rough sanding as it does not give a perfectly even and smooth finish in which case another sander may be used. Some machines contain a combination of disc and belt sander for rough and fine sanding.
A belt sander is used for smoothing and finishing the surfaces of wood or any other material. It works on an electric motor that operates a pair of drums with a continuous belt of sandpaper mounted on them. Belt sanders are mostly handheld and moved all over the surface to be sanded. They can also be fixed, in which case a workpiece needs to be moved over the sanding belt. Some combinations of belt and disc sanders are also available for multiple sanding.
Belt sanders work sideways and their action is considered aggressive, in which case belt sanders with variable speed are used to reduce the speed as the sanding gets finer. If fitted with a fine sandpaper, the belt sander can give a completely smooth and even surface. It also contains a system to store sawdust. It could be a vacuum to suck the dust particles away and into a collection bag, or it could be a simple cloth filter bag that is used in portable and small belt sanders.
Detail sanders are handheld sanders that have a small vibrating head and a triangular sandpaper piece attached to it. They are designed for sanding tight spaces, edges and corners. They are also referred to as corner sanders. Their triangular sandpaper pads are interchangeable and they are mostly used for tight spots such as chair spindles. They can also be operated with finger-shaped sandpaper pads to work in slots or grooves. As the name indicates, they are used for giving fine details and sanding narrow and tight spaces where a normal belt or random orbital sander will not be able to reach.
Spindle Sander is also known as an oscillating edge sander. It combines belt sanding with spindle sanding and can convert back and forth very easily. It provides accurate and fast sanding. Spindle sanders can work on wood as well as metal. It can be used for sharpening knives as well as for polishing materials. They are mostly stationary, and the workpiece or the object that needs to be polished is held against its rotating spindle for polishing or sanding. Spindle sanders are ideal for shaping curves and contours.
Sheet sanders are used for smoothing wood surfaces, but they can also work on metals and plastics. The sandpaper is clipped into the sheet sander before sanding. It can work both fine and coarse sanding as the degree of sanding can be varied by using suitable sandpaper. If the surface requires a lot of sanding, use coarse sandpaper; otherwise, use a fine sandpaper to get a smooth and even finish on the surface. The base plate of the sheet sander is rectangular in shape and sanding occurs due to the vibratory motion of the plate, which mostly vibrates at 1200 rpm. Sheet sanders are preferred for professional woodworking, unlike belt sander and random orbital sanders that can also be used at home.
These are powerful stationary machines that are usually more costly than your other sander types. They are used for smoothing out large surface panels, but in fact are very versatile and can be used for very many different types of projects. A serious woodworking shop can always benefit from having a good drum sander at its disposal.