Polishing Compound Cut Ratings: Why Brand Scales Do Not Match

A cut rating helps position a product within a manufacturer’s range. It is not automatically a laboratory value that can be compared with another brand’s number. A nine on one bottle and a six on another may refer to different scales, test conditions or marketing conventions.

Ask what the rating describes

Look for a technical sheet explaining the intended correction role, approved pads and machine types. If a cut/gloss chart has no stated method, use it as a relative guide within that range. Do not convert it into a predicted amount of clear-coat removal.

The same caution applies to sanding-mark claims. A statement that a system removes a particular sanding grade depends on the specified finish, abrasive process, pad and operating conditions. It does not authorise chasing arbitrary scratches on an unknown vehicle.

Compare systems in a practical test

Choose a representative surface and define the target defect before testing. Record the liquid, pad, machine movement, area and working method. Keep the starting condition and inspection process comparable.

Evaluate three separate results: useful defect reduction, finish quality after residue removal, and the work needed to reach the final standard. A fast cutting stage that requires lengthy refinement may not be the fastest complete system.

Do not rank by one number

A high cut figure does not mean a product is better for a car with light swirls. A high gloss figure does not mean it will remove deeper defects. The useful product is the one that performs the required role with a controlled process.

Also consider wipe-off behaviour, dust management, pad cleaning and compatibility with the next treatment. These factors affect practical efficiency even though they may not appear in a simple rating.

Keep comparisons honest

If you publish your own evaluation, identify the products and test conditions and show both corrected and remaining defects. Do not present an informal workshop impression as a universal scientific ranking. A defensible conclusion is specific: this combination produced this result on this paint under these conditions. That is considerably more useful than choosing the largest number on a label.

Continue reading

• Car Polish and Compound: A Complete Selection Guide
• Diminishing vs Non-Diminishing Abrasives in Car Polish
• Are Polishing Oils Hiding Remaining Paint Defects?

Browse the complete car polish and compound guide.

Manufacturer references

These references illustrate named product systems. Use the current instructions for the exact product, pad and machine in your own process.

• Polishing grades and system selection