Uploaded February 2026 | Updated September 2026, 2 weeks ago
Learn how to fix a bad rock polish on a flat lap by removing low spots, deep scratches and grit contamination. This beginner lapidary tutorial shows how to restart at the correct grit, use a Sharpie grid to flatten the stone and rebuild the surface through 180, 400, 600 and 1,200 grit before finishing with cerium oxide.
A final polishing pad cannot repair deep scratches or reach low areas that are not making full contact. When a stone stays cloudy, wavy or scratched, the solution is usually to return to the first abrasive stage capable of removing the deepest defect—not to spend more time on the final polish.
In this video, you’ll learn:
• How to diagnose a dull or uneven rock polish
• How low spots prevent an even finish
• How grit contamination creates deep scratches
• How to clean flat-lap discs between stages
• How to use a Sharpie grid to test flatness
• When to return to a coarser grit
• How to progress through 180, 400, 600 and 1,200 grit
• How to use cerium oxide on a felt polishing pad
• Why lighter pressure is important on finer stages
• How to control heat during final polishing
Choosing where to restart:
• Deep scratches, waves or low spots — return to a coarse corrective grit
• Fine scratches — return to the stage that can remove them
• Uniform satin finish with no visible scratches — move to final polish
• New scratches after changing discs — inspect for contamination
Dry the stone and examine it under a bright light before moving to the next stage. Water can temporarily hide scratches and make an unfinished surface appear more polished than it really is.
The final polishing compound demonstrated in this video is cerium oxide. Keep the stone moving, use light pressure and add water when needed to prevent excessive heat.
Chapters
00:00 Bad rock polish before and after
00:35 Why the original polish failed
01:14 Diagnosing low spots and contamination
02:27 Cleaning the flat-lap discs
03:08 Returning to 180 grit
03:35 Sharpie grid flatness test
05:03 Progressing through finer grits
07:08 Cerium oxide final polish
08:25 Before-and-after reveal
08:37 Why some defects remained
09:05 Most important polishing lessons
Verify those chapter times against the uploaded video before replacing the existing ones.
What does your failed polish look like—cloudy haze, deep scratches, low spots or small pits?
#RockPolishing #Lapidary #FlatLap #StonePolishing #WillORocks
Learn how to fix a bad rock polish on a flat lap by removing low spots, deep scratches and grit contamination. This beginner lapidary tutorial shows how to restart at the correct grit, use a Sharpie grid to flatten the stone and rebuild the surface through 180, 400, 600 and 1,200 grit before finishing with cerium oxide.
A final polishing pad cannot repair deep scratches or reach low areas that are not making full contact. When a stone stays cloudy, wavy or scratched, the solution is usually to return to the first abrasive stage capable of removing the deepest defect—not to spend more time on the final polish.
In this video, you’ll learn:
• How to diagnose a dull or uneven rock polish
• How low spots prevent an even finish
• How grit contamination creates deep scratches
• How to clean flat-lap discs between stages
• How to use a Sharpie grid to test flatness
• When to return to a coarser grit
• How to progress through 180, 400, 600 and 1,200 grit
• How to use cerium oxide on a felt polishing pad
• Why lighter pressure is important on finer stages
• How to control heat during final polishing
Choosing where to restart:
• Deep scratches, waves or low spots — return to a coarse corrective grit
• Fine scratches — return to the stage that can remove them
• Uniform satin finish with no visible scratches — move to final polish
• New scratches after changing discs — inspect for contamination
Dry the stone and examine it under a bright light before moving to the next stage. Water can temporarily hide scratches and make an unfinished surface appear more polished than it really is.
The final polishing compound demonstrated in this video is cerium oxide. Keep the stone moving, use light pressure and add water when needed to prevent excessive heat.
Chapters
00:00 Bad rock polish before and after
00:35 Why the original polish failed
01:14 Diagnosing low spots and contamination
02:27 Cleaning the flat-lap discs
03:08 Returning to 180 grit
03:35 Sharpie grid flatness test
05:03 Progressing through finer grits
07:08 Cerium oxide final polish
08:25 Before-and-after reveal
08:37 Why some defects remained
09:05 Most important polishing lessons
Verify those chapter times against the uploaded video before replacing the existing ones.
What does your failed polish look like—cloudy haze, deep scratches, low spots or small pits?
#RockPolishing #Lapidary #FlatLap #StonePolishing #WillORocks
