The aileron on rudder were sanded down to 350 grit which works REALLY well with the primer cured for a day. In fact 350 grit seemed to give the best balance between cut and contour without taking off too much material all over. I'm Very pleased. I filled a couple low spots then hung these up to be sprayed with 2 more coats of primer that will be lightly blocked, then sanded with 3000 grit like the wing. Again, the Enduro prime has been problem free. In fact, I noticed some orange peel last night when I shot the primer but woke up this morning to see it perfectly level. Amazing stuff when using 10% of the slow reducer.