Level Finish · Technical Test Report

Alpha P80 vs 3M Cubitron II: two controlled tests, published in full

Level Finish Alpha P80 cutting disc vs 3M™ Cubitron™ II P80. Two separate controlled tests on body filler, reported side by side and never combined. Test 1 is the P80 stage of a three-step progression series, run as timed trials of 2 minutes 30 seconds per product. Test 2 is a follow-up on a more premium body filler, run to a visually determined endpoint. The fillers and the timing methods differ, so each test stands on its own numbers. One pattern repeats in both: Alpha recorded the stronger removal results, and 3M recorded the lower average Ra. Both facts are published here.

What happened, in short

• Test 1, body filler, timed trials: Alpha recorded 27.431 mil of adjusted average removal vs 17.060 mil for 3M Cubitron II, 60.8% more measured removal. On surface finish, 3M recorded the lower average Ra: 3.438 µm vs 3.830 µm.
• Test 2, premium body filler, endpoint trials: Alpha removed material at 0.9039 mil/min vs 0.7777 mil/min for 3M, 16.2% more per working minute, and reached its endpoint in 157 seconds vs 220 seconds. On surface finish, 3M again recorded the lower average Ra: 4.1821 µm vs 4.4355 µm. Alpha's Ra readings were tighter: standard deviation 0.6515 µm vs 0.8596 µm.
• The honest summary: neither product won every category in either test, and this page does not pretend otherwise.

Test 1: timed P80 trial on body filler

Method. Test 1 is the first stage of a three-step progression series (P80, then P220, then P400); only the P80 stage is reported on this page. Each product's test area on body filler was sanded for 2 minutes 30 seconds. Removal was measured coordinate by coordinate using a conservative adjusted method: adjusted removal equals the starting depth minus the final depth, apparent gains are set to zero so they cannot offset real removal, and unresolved coordinate pairs are excluded. Final surface roughness was recorded as 7 Ra readings per product. The P80 final readings then became the starting condition for the next stage of the series.

Metric	3M Cubitron II P80	Level Finish Alpha P80
Adjusted total removal (all coordinates)	665.33	1,261.82
Adjusted average removal per coordinate	17.060 mil	27.431 mil
Median adjusted removal	14.500 mil	25.850 mil
Adjusted rate per coordinate per minute	6.824	10.972
Final average Ra	3.438 µm	3.830 µm

Alpha's adjusted average removal was 60.8% higher. Cubitron II recorded the lower final average Ra.

Test 1: the individual Ra readings

Ra is the measured arithmetic average surface roughness under the documented test conditions; lower is finer. All 7 readings per product, exactly as recorded:

Reading	Cubitron II final Ra (µm)	Alpha final Ra (µm)
1	2.875	4.273
2	1.166	4.236
3	4.075	4.414
4	4.414	3.850
5	2.814	3.360
6	4.440	3.404
7	4.285	3.275
Average	3.438	3.830
Median	4.075	3.850

Test 1: photographic record

Cubitron II P80, before the test	Cubitron II P80, after 2 min 30 sec
Alpha P80, before the test	Alpha P80, after 2 min 30 sec

The photographs document starting and post-test condition alongside the measurements. Visible residue on a used disc does not by itself quantify loading or remaining abrasive life, and no such percentage is claimed.

Test 1 stage finding: Alpha takes the P80 stage on removal, the principal job of a coarse shaping grit. Cubitron II takes the finish category with the lower final average Ra. Level Finish stage ratings for this test: Alpha 9.1 of 10, Cubitron II 8.0 of 10. These are Level Finish structured ratings from this test series, not third-party certification scores.

Test 2: follow-up trial on premium body filler

Method. The follow-up used a more premium body filler than the earlier test series, so its raw removal values are interpreted within this test only and are not a replication of Test 1. Each product was measured at 132 coordinate-matched locations before and after sanding, with 22 finished-surface Ra readings, full-disc and panel photography, and microscopy at ×500 and ×1000. Each trial ended when the surface appeared complete, and actual working time is the denominator for the removal rate. The panels began at closely matched average thicknesses: 28.1689 mils for Cubitron II and 28.1894 mils for Alpha, a difference of 0.0205 mil.

Metric	3M Cubitron II P80	Level Finish Alpha P80
Working time	220 sec	157 sec
Measured removal at observed endpoint	2.8516 mils	2.3652 mils
Removal rate	0.7777 mil/min	0.9039 mil/min
Post-test average thickness	25.3173 mils	25.8242 mils
Average Ra	4.1821 µm	4.4355 µm
Ra median	4.2450 µm	4.4865 µm
Ra standard deviation	0.8596 µm	0.6515 µm
Ra range	3.447 µm	2.242 µm

How to read the removal numbers: Cubitron II removed more in total at its endpoint because it ran 63 seconds longer. Endpoint removal is therefore reported as observed and is not scored as a productivity category. Per actual working minute, Alpha removed 16.2% more, and Alpha reached the visually determined endpoint 63 seconds sooner. Cubitron II produced the lower average Ra, by 0.2534 µm. Alpha produced the lower Ra variability, with the smaller standard deviation and the narrower range.

Sensitivity context only: extending Alpha's observed average rate mathematically to 220 seconds gives approximately 3.314 mils. That is a constant-rate projection, not a measured result, and it is not scored.

Measurement note: three coordinate differences came back slightly negative (Cubitron II D2 at -1.3 mil and C22 at -0.1 mil; Alpha L12 at -0.2 mil). They were preserved as recorded and treated as measurement or coordinate-placement variability.

Test 2: disc condition and microscopy

No gross physical failure was observed on either disc. Post-test particulate was observed on both products, distributed nonuniformly on both, and abrasive structures remained exposed on both. No quantitative wear or loading percentage was established for either product, and because Alpha worked 63 seconds less, the photographs document each product at its own endpoint rather than at equal wear time. No disc-condition winner is claimed.

Test 2: category ratings

Category	Cubitron II	Alpha	Finding
Removal per actual minute	8.6	10.0	Alpha
Time to visual completion	7.1	10.0	Alpha
Average Ra (lower is better)	10.0	9.4	Cubitron II
Ra consistency	7.6	10.0	Alpha
Macro disc condition	10.0	10.0	Tie
Microscopic condition	9.0	9.0	Tie

Unweighted six-category average: Cubitron II 8.72 of 10, Alpha 9.73 of 10. Application-weighted score: Cubitron II 8.55 of 10, Alpha 9.81 of 10. The weighting is productivity-focused and disclosed in full: removal per minute 30%, time to visual completion 20%, average Ra 15%, Ra consistency 15%, macro disc condition 10%, microscopic condition 10%. Quantitative scores use proportional scoring with the leading result set at 10.0. These are Level Finish ratings for this trial, not third-party certification scores.

Which P80 fits which priority: choose Cubitron II when the priority is the lower average measured P80 Ra. Choose Alpha when the priority is removal efficiency per working minute, shorter observed working time to the endpoint, and tighter measured Ra grouping.

How to read these two tests

Different fillers, different timing methods, one consistent pattern. In a fixed-time trial, Alpha removed 60.8% more per coordinate on average. In an endpoint trial on premium filler, Alpha removed 16.2% more per minute and finished sooner. In both tests, 3M recorded the lower average Ra, and in the follow-up, Alpha's Ra readings grouped tighter. P80 is a shaping stage, not a finishing stage: which metric matters more depends on how much stock has to come off and how the shop runs the refinement steps that follow. That call belongs to the technician. Our job is to publish the measurements exactly as recorded and let you decide for yourself.

More test results

Omega P2000 vs 3M Purple P2000, filmed side by side on one panel: see the filmed test results. More reports are filed here as testing is completed.

Notes and limitations

Each test is a single controlled trial under its documented conditions, and the results describe those trials. Test 2 endpoints were visually determined. Total repair time, cost, rework, and downstream refinement time were not measured in either test. Photographic and microscopic evidence is qualitative. Ratings are Level Finish structured ratings based on the documented data, weighted as disclosed, and are not third-party certification. Results from one grit or substrate do not transfer to another.

Frequently asked questions

How much more material did Alpha P80 remove in the timed test?

Alpha recorded 27.431 mil of adjusted average removal per coordinate vs 17.060 mil for 3M Cubitron II, which is 60.8% more measured removal in the same 2 minutes 30 seconds.

Which P80 disc left the finer surface?

3M Cubitron II, in both tests. Its final average Ra was 3.438 µm vs Alpha at 3.830 µm in Test 1, and 4.1821 µm vs 4.4355 µm in the premium filler follow-up.

Why are there two P80 tests with different numbers?

They are different trials. Test 1 ran both products for a fixed 2 minutes 30 seconds on body filler. Test 2 was a follow-up on a more premium body filler, run to a visual endpoint with each product timed separately. Different fillers and timing methods produce different absolute values, so the tests are reported separately and never combined.

Did 3M remove more material in the follow-up test?

At its observed endpoint, yes: 2.8516 mils vs 2.3652 mils for Alpha. It also ran 63 seconds longer (220 vs 157 seconds). Per working minute, Alpha removed more: 0.9039 mil/min vs 0.7777 mil/min.

So which disc won?

Neither product won every category in either test. Alpha showed the stronger removal results in both; 3M recorded the lower average Ra in both. We publish both metrics so technicians can decide which matters more for their process.

Level Finish · St. George, Utah · level-finish.com · Sources: Level Finish Expanded Master Abrasive Comparison Test Report (September 2026), P80 section, and Controlled P80 Abrasive Follow-Up Comparison (October 2026). Page prepared November 13, 2026. All numbers transcribed exactly from those reports; no values added or altered.