How to Cut & Buff Automotive Paintby Thomas Ferraioli
Creating a high gloss shine on your car takes more than a bucket and sponge. Cutting the paint---the process of stripping off a micro-thin layer of the finish---is necessary to keep that high gloss, showroom shine intact. If you just need to paint a section of your vehicle to create a smooth, factory finish, cutting will still be necessary. Cutting can be done with an abrasive cream; for paint jobs that need extra work, sanding with wet sandpaper will be necessary.
Cutting the Paint With Sandpaper
Soak sandpaper in a bucket for at least 15 minutes; overnight is ideal. The clear coat finish from the factory is thin and can easily be removed; use 3000-grit sandpaper. For do-it-yourself paint jobs, 1200- to 2000-grit sandpaper can be used. (Sandpaper designed to be immersed in water without falling apart can be found at an automotive store.)
Clean the car of dirt and grime; let dry completely. If the car is clean to begin with, then spray lightly with a sanding lubricant, then wipe clean with a soft, lint-free cloth.
Sand the paint in a back-and-forth motion. Use the 1200-grit sandpaper first if it is a self-paint job, or the 3000-grit if it is a factory paint job. Keep the sandpaper wet by misting with a squirt bottle or hose. Avoid dipping the sandpaper into the bucket, as this will contaminate the paper still in the bucket. Rinse the area periodically to check your work.
Repeat with a 2000-grit sandpaper if you are sanding a self-painted area. The fine paper makes the paint smoother as it removes the grit lines from the 1200-grit paper. When completed, the paint will look dull and hazy.
Attach a wool buffing head to your rotary buffing machine. Though soft to the touch, a wool buffing pad will create a fair amount of friction on the paint's surface. Prep the pad with a buffing and sanding lubricant.
Apply a cutting cream or compound to the car. Buff with the wool bonnet at 1500 rpm. Buff a small area, about 2 feet-by-2 feet. Check to see if the paint is becoming shiny. If not, turn the speed up an additional 100 rpm. Also, make sure there is enough cutting cream on the pad to leave an oily film. If not, you are working too dry.
Switch the wool bonnet for a foam buffing pad. Prep with a buffing and sanding lubricant.
Apply a small amount of polishing cream to the car. Work it in using a back and forth motion with the buffer set at 1300 rpm. Light pressure is needed for this final buffing step. Keep the buffer moving. Apply more polishing cream as needed.
- Keep the buffer moving to avoid burning the paint.
- Always work in a cool, shaded area. Direct sunlight will heat the paint causing the product to dry too quickly.
- Do not tilt the buffer in an effort to buff-out a mark. This can burn the paint or cause uneven swirl marks.
Items you will need
- Rotary polisher
- Wool cutting pad
- Soft puffing pad
- Sanding block
- Cutting compound
- Polish / Wax
- red car 3 image by Viachaslau Makouski from Fotolia.com