Some fiberglass fillers can be tinted to a variety of colors. If you tint your filler, you can skip painting your repair in many circumstances. Do not run the brush accessory in excess of 15.000 rpm.
Step 1
Hull blisters are common on boats. With prompt attention they´re not harmful.
Step 2
Grind out the blister with a 144 high-speed cutter. Recommended speed: 15.000 rpm.
Step 3
Clean the hole with the 442 carbon steel brush. Wipe away dust with a cloth dipped in paint thinner. Recommended speed: 15.000 rpm.
Step 4
Finally, fill the hole with fiberglass filler and resin. When dry, scuff the surface before painting.