Abrasivies

Perma-Grit 8C-tool assortment. Cuts through fiberglass, epoxy and structural adhesive like a... warm knife through really cold butter. But it's still better than any other hand tool for forming composites. Aircraft Spruce

When it comes to abrasives, like most other tools, cheap is not the way to go. I recently ran through some low-cost 36 grit sheets on an air-file. They lasted about 5 minutes each and didn't cut much material. A single 3M Imperial (Purple) sheet cut through material 20 times as fast (I kid you not) and last 20 times as long. Even though they cost about $1.50 each, it still saves a bunch of money over the cheaper sheets.