I have a Porter Cable belt sander that I haven't used for at least 10 years. The sanding belts are all at least 10 years old.

I actually had a need to use it recently, on 3/4" plywood (don't ask), and every time I started sanding, each belt would break in roughly 30 seconds. I had a failure rate of 100%.

I checked the tracking each time, and the sandpaper didn't go off one side or another, it was just when sanding they would break.

Is it just that the adhesive on the tape on the belts had gone bad after 10 years, or is there something else I'm doing wrong? I literally blew through 10 belts in no time at all.