Flap Disc Grit Selection: A Practical Guide
Grit selection should be driven backwards from what happens after grinding. If the part is going straight to paint, you need a finer scratch than if it is going to be welded over.
Quick reference
- P40 — heavy weld blending, stock removal
- P60 — general blending, most common shop grit
- P80 — finishing before primer
- P120 — light deburring and pre-polish
Type 27 or Type 29
Type 27 flat discs suit flat surfaces and edge work. Type 29 conical discs put more abrasive on the face and cut faster at a shallow angle, which is why they dominate weld blending.