When to use variable speed on a sander
You can use the button to set the sanding speed. Generally, a low speed is ideal for flat surfaces and a high speed when you want to sand down faster. A higher sanding speed isn’t necessarily always better in practice. A low speed is preferable to sand a painted surface, for example. This prevents the paint from getting hot and spreading out or clogging up the sanding sheet. You’ll therefore have to think about the optimal sanding speed for each specific job.