The orbital sander is probably the most frequently used tool in the workshop. It is the last tool you will use before you add a finish to your project. How you sand can make or break your piece. Do it right and you will love your finished piece.
This sander is different from the belt sander and finishing sander in that it vibrates in little loops as it spins around in circle. So you have these little spinning motions inside one large circular motion. This makes the sander more efficient and as important, it reduces the chances of sanding marks when used properly.
There are two types of sander pads that can be associated with the orbital sander. The hook and loop and the PSA sander pads.
The hook and loop has loops on one surface and hooks on the other. This type of system is better known as Velcro. The sandpaper discs remove easily and are not ruined in the process.
PSA or pressure sensitive sand paper, has a sticky adhesive on the back of the sandpaper. The label paper is peeled off and stuck to the sanding pad. This paper is less expensive but there is one major drawback. When the paper is removed, if anything gets on the sticky side, it will not stick. So any bit of sawdust will render the paper useless. This makes it hard to move from one grit to another.