Electric sanders make the job of sanding large areas a lot easier than using 'elbow grease' and sandpaper on a sanding block. Various types of electric sanders are available and each suit particular jobs.
One thing to remember when using any type of electric sander is to keep it moving, leaving the sander in one place will 'over sand' that place and make it stand out from the surrounding area.
When sanding, always change the sandpaper from coarse down through the grades to fine as you achieve the finish you require; don't expect one grade of sandpaper to do all the work.
There are three basic motions used in sanders;
- Orbital - the whole sanding plate moves in a small circle causing each grain of abrasive to move likewise.
- Belt - this gives sanding in one direction so any scratch marks will be along the direction of the belt.
- Rotary - where the whole sanding disc goes round - the outer edge moves faster than the centre so the surface is subjected to varying degrees of sanding.
Things to look for:
- Electric - either 220/230v or 110v - can use on site where mains power or a 110v transformer is available.
- Cordless - ideal for using where mains supply is not available. Look for one with a Lithium-Ion battery as these last longer. Having a detachable battery is also useful, you can have a spare battery fully charged ready to insert when required rather than having to wait while a single battery is recharged.
- Dust bag - collects the dust as it is produced - generally not completely effective, you still end up with dust everywhere - just less.
The Orbital sander is probable the most common type of electric sander available. They are available with rectangular, square or round base plates. When using an orbital sander, there is no need to worry about the direction of wood grain.
Some rectangular and square models, clip the sandpaper to the base plate, other models need special sanding paper with an adhesive back which sticks to the base plate. Models with round base plates require special sanding discs which adhere to the base plate.
Rectangular and square sanders usually come in various sizes to accommodate 1/2, 1/3 or 1/4 sheet of a normal sheet of sandpaper.
Detail sanders are effectively Orbital sanders with small, usually triangular, base plates which can fit into awkward areas such as window frames, small items or furniture etc.
Special, self adhesive sandpaper needs to be used.
The small, pointed shaped base plates make them ideal for sanding into corners where other types of sander cannot not reach.
Belt sanders generally remove material quicker than Orbital sanders and can make light work of sanding but it is generally harder to get as good a finish as can be achieved with an orbital sander.
Care needs to be taken to use a belt sander 'with the grain' and not 'against' or 'across' the grain as sanding marks can otherwise easily result.
Belt sanders are available as either hand-held or bench mounted - the latter being easier to use where the workpiece is small.
Bench sanders are usually belt sanders often incorporating a rotary sander. They are used not just for sanding but for shaping as well, these machines are powerful and make easy work of rapid removal of material from the work piece.
File or finger sander
File or finger sanders have a very narrow (in the order of 12.5mm) sanding belt which can get into narrow areas.
Not really common other than as an accessory for a power drill or fitted as a bench mounted sander.
These round abrasive discs just spin, the outer part going fast than the centre. This makes them effectively useless for achieving a good finish on large areas of flat surface.
Floor sanders would normally be hired by a diy'er when required rather than purchased.
There are basically two types of Floor sander:
- The large drum machine which is used by walking behind - like a lawn mower across a wooden floor.
- The edging sander used to sand the edges of a floor where the drum machine cannot reach.
Most good hire shops will stock both types and supply the abrasive papers.