Disc and orbital sanders

Disc sander

The original electric sander is likely to have been sandpaper attached to a disc fitted to end of a power drill. If you've got a drill, this is still the simplest and cheapest option. Rotary sanding discs can remove a lot of material in not much time.

Unfortunately, it's easy to leave swirl marks and gouges that are difficult to remove. Getting a good finish with a disc sander takes a bit of practice. They're more suitable for smoothing rough timber or removing old paint.

Orbital sander

These sanders use an oblong rubber pad with sandpaper attached, that moves very fast in a circular motion just a few millimetres in diameter. This movement is difficult to see, but you can feel the vibration in the handle of the machine.

Orbital sanders are designed for fine surface finishing, not for the removal of large amounts of material. They are easy to use, although you need to keep the pad moving at all times or tiny swirl marks can appear.

The pad is oblong so you can get into corners.

Detail sander

A variation on the orbital sander with a triangular-shaped sole. This allows you to reach awkward places like around window frames.

The forward-facing tip gets most wear, so the sole can be adjusted to set each tip to the front. Some versions have a sole shaped rather like a clothes iron.

Random-orbital sander

A combination of disc and orbital. The round disc moves in tiny circles, like an orbital, but is also free to rotate. The net effect is that the machine removes material faster than an orbital, and doesn't leave score marks like a disc, or swirl marks like an orbital.

Random-orbital machines - especially models with adjustable dual orbits - provide the best combination of rapid material removal, ease of use and good finish. But the round pad cannot get into corners.