Is 3M Letting Welders Down With This New Disc?

Product reviewed

3M Cubitron 3 flap/petal disc (compared heavily against the 3M Cubitron 2, and evaluated versus 39 other petal discs in the channel’s testing database).

Main features / claims mentioned

• Precision-shaped grain with curved edges designed to split into sharp corners for aggressive cutting.
• 3M claim: removes 49% more material than Cubitron 2.
• Designed to maintain cutting performance longer under load and heat (based on test results).

Test method & user experience setup

• The reviewer built an apparatus to test flap discs:
  • A 12-inch workpiece is lowered onto the disc.
  • The disc is loaded with weights (4 lb and 8 lb).
  • Tests run for 20 minutes or end early if the disc stops cutting effectively or crumbles/salts.
  • Uses cold and hot/heat-added conditions.
  • Includes graphing material removal vs. time.
• They also note real-world workshop use for “the past few weeks.”

Key results (material removed + durability)

4 lb pressure (cold)

• Cubitron 2: lasted 13 min, removed ~19 inches, then got greasy.
• Cubitron 3: removed ~3 in in 1 min, >10 in by 4 min, continued to the end and removed ~41 inches.
• Result comparison: Cubitron 3 removed ~22 inches more than Cubitron 2 overall.

4 lb pressure (hot/with heat)

• Cubitron 2: ~13 min, ~16 inches before getting greasy.
• Cubitron 3: got salty around ~15 min, but still removed ~37 inches.
• Result comparison: Cubitron 3 removed ~21 inches more than Cubitron 2.

4 lb low-speed (slower sander)

• Both performed more similarly, but Cubitron 3 still ran full 20 minutes and removed ~10 inches more than Cubitron 2.

8 lb pressure (cold)

• Cubitron 2: edge badly degraded; stopped early (smoked at just over 4 min) after removing ~11.5 inches.
• Cubitron 3: removed ~3+ inches in the first minute, continued until ~6 min when it smoked; removed ~21 inches and still had abrasive left.
• Result comparison: Cubitron 3 removed ~10 inches more and ran ~2 minutes longer.

8 lb pressure (hot/with heat) — “most challenging”

• Cubitron 2: burnt out around ~4 min, removed ~11 inches.
• Cubitron 3: removed ~5 inches in the first minute, ~29 inches by 6 min, cut aggressively for full 20 min, removed ~90 inches (about 3× the “original schedule”), and still had abrasive left.
• Edge/wear: Cubitron 3 had more even wear and outperformed again, despite edge load.

Pros mentioned

• Much higher material removal than Cubitron 2 in every major scenario tested.
• Stays cutting longer (often reaches the full 20 minutes where Cubitron 2 fades early).
• Faster early cutting (especially under high load/heat).
• Best performance in the hardest test (hot + 8 lb pressure).
• Workshop use impression: “very aggressive,” good for quick removal, chamfers, and weld removal.

Cons / trade-offs mentioned

• “Extremely aggressive”: can be too aggressive and you can “get too deep.”
• Performance depends on pressure:
  • Cubitron 3 “loves” the right load; reviewer suggests light pressure may be better in some hot scenarios.
• Economics: compared against the wider group, it’s not the most economical overall (you pay more for speed/aggression).
• Aggressiveness can be a huge advantage or a redundancy depending on whether you’re doing bulk removal or finishing.

Comparisons vs Cubitron 2 (direct)

Cubitron 3 consistently:

• Removes more material,
• lasts longer under load,
• suffers less performance degradation,
• and shows better edge/wear behavior (more even wear; less catastrophic edge failure).

Comparisons vs other petal discs (broader market test of 39 discs)

• Cost-to-footage / volume: Cubitron 3 removed ~47.5 inches, described as more than double the average of other discs.
• Grinding time vs. material removed:
  • Cubitron 3 average: ~15 minutes to remove ~47 inches.
  • Some discs may last longer but remove material much more slowly.
• Cost per inch vs cutting speed: Cubitron 3 ranks well—fast and high removal—but isn’t automatically the cheapest-per-life option.
• Overall economics (cost of a minute vs cost per inch):
  • Cubitron 3 ranks pretty well, but is not the most economical disc in the group.
  • Framed as a performance-first compromise.

Buying guidance / recommendations (as stated)

• If you prioritize maximum speed and removal (and price isn’t the main concern): Cubitron 3 is hard to beat.
• For medium-duty work / smaller finishing / tasks where you prefer more frequent disc changes: reviewer prefers Steel Savage (better removal per dollar in their tests).
• For professionals sanding all day who need speed: reviewer recommends 3M Cubitron 3.
• Reviewer also recommends having both cheap + high-quality discs on hand.

Unique points mentioned (consolidated)

1. 3M claims +49% material removal vs Cubitron 2.
2. Precision-shaped grain designed to create sharp cutting corners.
3. Testing apparatus: 12-inch workpiece, gravity load, 20-minute runs, cold/hot, 4 lb and 8 lb, plus slower-speed trials.
4. Stopping criteria: disc stops cutting effectively, becomes salted/greasy, or crumbles.
5. Multiple quantified results showing Cubitron 3 removes substantially more than Cubitron 2 across conditions.
6. Hot tests still strongly favor Cubitron 3.
7. Under extreme stress (hot + 8 lb), Cubitron 3 shows its best performance: ~90 inches removed, full duration, abrasive remaining.
8. Edge/wear observations: Cubitron 2 suffers severe edge destruction; Cubitron 3 wear is more even.
9. Broader comparison dataset: 39 petal discs, price range ~$2 to $20+ per disc.
10. Cubitron 3 removes ~47.5 inches, >2× average.
11. Cubitron 3 average grinding time ~15 min for ~47 in removal.
12. Aggressiveness can be an advantage (bulk removal) or a drawback (finishing risk).
13. Economics: good but not best overall economical; performance costs more.
14. Steel Savage recommended for value/frequent changes; Cubitron 3 for speed/pros.

Speaker / role views (single main speaker implied)

• Primary reviewer (testing + data + workshop use):
  • Concludes Cubitron 3 outperforms and “crushes” Cubitron 2 by data and visual inspection.
  • Recommends Cubitron 3 for fast, aggressive material removal; suggests Steel Savage for value/finishing/frequent replacement.

Concise verdict

Buy the 3M Cubitron 3 if you want the fastest, most aggressive material removal and can accept higher cost. The testing shows it dramatically beats Cubitron 2 and performs extremely well versus a wide range of petal discs.

Choose a cheaper/value option (e.g., Steel Savage, per the video) if you need better cost-per-dollar or more controlled finishing with frequent disc swapping.