Separate removable surface haze from hard-coat failure, crazing, and deep damage before any abrasive touches a flight-critical canopy.
Level metallic epoxy without creating light and dark sanding lanes by checking pigment depth, using supported passes, and testing the final clear system.
Check deep-pour epoxy cure state, flatten it with supported passes, and distinguish soft-resin smearing from ordinary abrasive loading.
Refine and polish a cast-acrylic edge by replacing each scratch pattern, controlling heat, and using a compatible compound system.
Prepare decorative chromed plastic for repainting with a minimal test-driven scuff while avoiding breakthrough to the base polymer.
Level a sound ski or snowboard sidewall repair while protecting the base, steel edge, bevel, and original profile.
Inspect carbon-fiber drone arms for structural damage, refine only sound cut edges, and verify the clear-coat system on a sample.
Black spots usually come from deterioration behind the glass, so front-surface sanding cannot restore the missing reflective layer.
Compare planing, scraping, and sanding with a controlled three-strip dye test, judging figure clarity, color consistency, tool tracks, and geometry.