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Scratches

Car paint layers

  1. Clear Coat (40-50 microns)
  2. Base Coat (10-25 microns) - car paint color
  3. Primer (20-30 microns)
    • Bare metal/plastic/fiberglass doesn't hold paint well
    • Chemically bonds to surface, also sealing surface from rust
    • Etching Primer
      • First layer (using contains mild acid, phosphoric acid) to "bite" into bare metal
      • Thin film, needs supplemental epoxy/urethane primer
      • Used for aluminum panels (generally higher end, not honda/toyotas)
    • Epoxy Primer
      • Two parts: resin + hardener
      • Not as strong as etch as it mechancial adheres
      • Needs to be sanded to adhere
      • Also pretects from rust
    • Urethane Primer
      • 2k version sprayed thick and sanded down
      • Used ontop of epoxy primer
  4. 180-220 grit sanding on epoxy primer
  5. Sealer (optional)
  6. Basecoat
    • Color of car
  7. Clearcoat
    • Protects from UV, scratches, chemicals
    • Gives gloss & depth

How polish works

Car polish has fine abrasives

- sponge just moves polish around
- else sponge just moves on top of clear coat, possibly burning it
- secondary, the polish acts as a lubrication to prevent burns
- the pads get softer with higher grit to provide less force

Repair clear coat

Polishing pad + compound acts like super-fine sandpaper — it shaves down a microscopic layer of clear coat until the scratch is level with the surrounding surface

Compound is generally just a more aggressive version of liquid polisher, used like sandpaper

ytb - buff w/ sponge pads

  1. clean panel with car shampoo or soap to make sure grit does scratch surface again
  2. buffing [sponge pads] for polishing/waxing
    • Orange (Coarse) - Standard Grade Cutting Pad, Excellent For Enamels, Acrylics And Urethane.
    • Yellow & Blue (Medium) - Polishing Pad, Final Cutting, Polishing Or Glazing Clear Coat Surfaces
    • White & Black (Extra Fine) - Finishing Pad, Provides A Rich Swirl-Free High Gloss Finish.
  3. Held in place w/ velcro
  4. Damp polisher with water and run to remove excess
  5. Pour a circle of polishing compound on sponge
  6. Start on low on car to prevent throwing off the compound
  7. Increase speed when compound embedded into sponge
  8. Add some water if gets too dry
  9. wipe with microfiber cloth
  10. Spray with wax and rub microfiber cloth over it

Polisher - 650W (no need for more power)

Microfiber’s ultra-fine fibers lift dirt away instead of dragging it. Doesn't leave lint like cotton. Can hold 8x its weight in liquid.

  • 300–400 GSM grams per square meter
  • thick enough to be safe, but not so plush they soak up all your polish before wiping
  • higher gsm is thiccer

Paint Touch Up

Purchaseable small liquid cartridges of paint specific for your car color

NOTE: Paint may not match if car is older as UV rays "damage" color of paint over time

  • Additionally, the darker the paint, the lighter the touchup paint will be because the clearcoat darkens it
  • However, due to differences in clear-coat, the darker touchup won't match darker cars

Equipment

Drill Speed

  • Low-speed polishing: 500–1500 RPM
  • Medium-speed cutting/polishing: 1500–2500 RPM
  • High-speed (pro-only, rotary polishers): 2500–4500+ RPM

Drill Torque

  • polishing requires only ~50 in-lb (5–6 Nm)

harbor frieght $15 cordless drill