Level Finish · Technical Test Report

Alpha P600 vs 3M Cubitron II 737U: primer refinement, measured

Level Finish Alpha P600 disc vs 3M™ Cubitron™ II Hookit™ Clean Sanding Abrasive Disc 737U P600. A controlled comparison on high-solids 2K primer, in two phases: a 40-second controlled test, then an extended-use endurance phase with the same discs. The categories split. Alpha recorded far higher removal, the tighter finish distributions, and the more uniform endurance pattern. Cubitron II recorded the lower average Ra in both phases. Both sides are published here. Note: this is the Alpha P600 comparison against Cubitron II. It is a different test from the Omega P600 comparison against Kovax / Eagle Sky, which is reported separately.

The gridded primer test panel before sanding, with its coordinate field for matched depth readings.

What happened, in short

• Material removal (40-second test): Alpha recorded an adjusted average of 4.998 mil per valid coordinate vs 2.196 mil for Cubitron II, 127.6% higher, with positive removal at 97.30% of coordinates vs 83.13%.
• Initial finish: Cubitron II recorded the slightly lower average Ra, 0.395 µm vs 0.409 µm. Alpha's readings were tighter: standard deviation 0.026 µm vs 0.045 µm.
• Endurance finish: Cubitron II again recorded the lower average Ra, 0.284 µm vs 0.444 µm, and Alpha again the tighter distribution. The observed endurance pattern differed: large pigtail-type patterns on the Cubitron II area, a comparatively uniform pattern on the Alpha area. That is a visual observation; this test does not establish its cause.
• The honest summary: Alpha took removal, consistency, and pattern. Cubitron II took average Ra in both phases. The report's overall finding, for the primer-refinement job P600 does, is Alpha; the category table below shows every split.

Method

The initial test surface was the high-solids 2K primer carried forward from the previously documented P80, P220, and P400 sequence panels. In the controlled phase, each product made seven controlled up-and-down passes over 40 seconds. Depth was read before and after at grid coordinates, and removal was calculated per coordinate (pre-test minus post-test), then adjusted conservatively: apparent increases were set to zero so they cannot offset real removal. The two panel areas did not begin at equivalent average depth (mean exact baseline 58.202 mil for the Cubitron II area, 52.370 mil for the Alpha area), so the comparison uses coordinate-matched change, not final-depth averages. Nine Alpha pre-test locations exceeded the depth reader's limit of 78.740 mil; five of them had measurable post-test values and support minimum confirmed removal totaling more than 26.001 mil. Those are lower bounds, reported separately and kept out of the averages below. Four had no usable post-test value and were excluded. Exact matched pairs: 83 for Cubitron II, 74 for Alpha. Seven final Ra readings were collected per product. In the endurance phase, the same discs sanded an additional 1 minute 55 seconds each (2 minutes 35 seconds total accumulated use) on a separate high-solids-primer-over-direct-metal area, with five Ra readings per product. The two phases used different areas and are evaluated independently.

Results: material removal, 40-second test

Adjusted removal	3M Cubitron II P600	Level Finish Alpha P600
Adjusted mean per valid coordinate	2.196 mil	4.998 mil
Adjusted median	1.100 mil	5.350 mil
Adjusted total removal	182.270 mil	369.830 mil
Adjusted sample standard deviation	2.057 mil	2.040 mil
Maximum adjusted removal	7.500 mil	9.800 mil
Positive-removal frequency	83.13% (69 of 83)	97.30% (72 of 74)

Alpha removed 2.802 mil more per valid coordinate on average, the 127.6% higher adjusted result. The near-equal standard deviations show the higher average was not accompanied by greater coordinate-level spread.

Adjusted average removal per valid coordinate (mil), 40-second test.

Results: surface finish, 40-second test

Final Ra (7 readings each)	3M Cubitron II P600	Level Finish Alpha P600
Average Ra	0.395 µm	0.409 µm
Median Ra	0.380 µm	0.419 µm
Ra standard deviation	0.045 µm	0.026 µm
Ra range	0.133 µm	0.066 µm

Cubitron II takes the average-finish category by 0.014 µm. Alpha takes consistency, with the lower standard deviation and the narrower range. All 14 readings, exactly as recorded: Cubitron II 0.483, 0.404, 0.413, 0.359, 0.374, 0.380, 0.350. Alpha 0.419, 0.422, 0.432, 0.435, 0.376, 0.410, 0.369.

Results: extended-use endurance

Endurance Ra (5 readings each)	3M Cubitron II P600	Level Finish Alpha P600
Average Ra	0.284 µm	0.444 µm
Median Ra	0.273 µm	0.441 µm
Ra standard deviation	0.050 µm	0.026 µm
Ra range	0.135 µm	0.063 µm
Observed pattern	Large pigtail-type patterns	Comparatively uniform

All 10 endurance readings, exactly as recorded: Cubitron II 0.273, 0.283, 0.367, 0.232, 0.265. Alpha 0.410, 0.429, 0.466, 0.441, 0.473. Average Ra and pattern uniformity measure different aspects of finish quality: an average does not capture isolated pigtail scratches. The report also notes the earlier P400 endurance test showed the same directional pattern distinction, with no numerical trend calculated between them.

The endurance panel after both test areas were sanded and cleaned.

The report's combined performance figure: initial Ra, endurance Ra, and adjusted stock removal by coordinate. The endurance results are evaluated independently and are not a direct Ra progression from the initial test surface.

Disc condition, as documented

Before the test, the photographs show the Alpha disc's hole field and center opening appearing more concentric with the disc edge, and the Cubitron II pattern appearing offset, with the center opening displaced from the geometric center. This is a photographic observation only: the photographs were not taken against a dimensional reference, no concentricity measurement was performed, and the observation does not by itself establish anything about sanding performance.

After use, the Cubitron II face showed visible, uneven residue accumulation with localized packing; the Alpha face showed residual material distributed more evenly. Neither disc showed major tearing, delamination, or gross edge failure, and both backings appeared intact. These are comparative visual findings; they do not quantify loading, retained cut rate, or remaining life.

Category results and the report's overall finding

Category	Leader	Basis
Adjusted removal per coordinate	Alpha	4.998 vs 2.196 mil, 127.6% higher
Positive-removal frequency	Alpha	97.30% vs 83.13%
Initial average Ra	Cubitron II	0.395 vs 0.409 µm
Initial Ra consistency	Alpha	SD 0.026 vs 0.045 µm
Endurance average Ra	Cubitron II	0.284 vs 0.444 µm
Endurance Ra consistency	Alpha	SD 0.026 vs 0.050 µm
Endurance observed pattern	Alpha	More uniform; Cubitron II showed large pigtail-type patterns

The test report's overall finding: for the P600 primer-refinement objective, efficient refinement with a stable, predictable finish and useful extended-use behavior, the report names Level Finish Alpha the overall winner of this test, and Cubitron II the fit where the lowest measured average Ra is the dominant priority. That finding reflects the documented conditions of this test, not third-party certification.

The report's category winners and shop-fit summary.

How to read this test

P600 is a refinement grit, and this test measured three different things that are easy to blur: how much primer comes off, the average roughness left behind, and how evenly and cleanly the disc keeps working. Alpha and Cubitron II split those results. If the priority is refinement throughput with a consistent, uniform finish, the removal, consistency, and pattern results point to Alpha. If the single priority is the lowest arithmetic-average Ra, both phases point to Cubitron II, with extended-use pattern uniformity to monitor. We publish every category so the choice can be made on the full record, not a headline. Decide for yourself.

More test results

Alpha P80 vs 3M Cubitron II, two controlled tests: see the P80 test results. Alpha P180 vs 3M Cubitron II, two controlled tests: see the P180 test results. Omega P1500 vs 3M Purple 260L: see the P1500 test results. Omega P2000 vs 3M Purple P2000, filmed: see the filmed test results. More reports are filed here as testing is completed.

Notes and limitations

This is a single controlled comparison under its documented conditions, and the results describe this test. The initial and endurance phases used different test areas and are not a direct Ra progression. Instrument-over-range Alpha values are reported as lower bounds and excluded from the averages. Adjusted removal is a conservative coordinate method, not a direct volumetric measurement. Ra sampling does not independently characterize isolated scratch defects across an entire surface. Visual evidence does not establish loading mechanisms, extraction behavior, or the cause of the observed pigtail-type patterns. Results from one grit or substrate do not transfer to another.

Frequently asked questions

Is this the same test as the Omega P600 comparison?

No. This page reports Alpha P600 against 3M Cubitron II 737U on high-solids primer. The Omega P600 comparison is against Kovax / Eagle Sky K-600, a different product, opponent, and dataset, reported separately.

Which P600 disc removed more primer?

Alpha. Its adjusted average removal was 4.998 mil per valid coordinate vs 2.196 mil for Cubitron II, 127.6% higher, with positive removal at 97.30% of its coordinates vs 83.13%.

Which P600 disc left the lowest average Ra?

Cubitron II, in both phases: 0.395 µm vs 0.409 µm in the controlled test, and 0.284 µm vs 0.444 µm in the endurance phase. Alpha's Ra readings were the more consistent set in both phases.

What were the pigtail-type patterns?

Large spiral-type scratch patterns observed on the Cubitron II endurance area after extended use; the Alpha endurance area was comparatively uniform. The observation is photographic, and the test does not establish what caused the difference.

Level Finish · St. George, Utah · level-finish.com · Source: Level Finish P600 Abrasive Comparison Test Report (September 2026), 3M Cubitron II 737U vs Level Finish Alpha. Page prepared November 13, 2026. All numbers transcribed exactly from that report; no values added or altered.