Compound Grit Equivalents: Why a Liquid Is Not a Sandpaper Grade

Calling a compound ‘equivalent to P3000’ can confuse two different systems. Sandpaper grades describe abrasive grading within a particular standard; a polishing liquid works through a compound-pad-machine combination. A sanding-mark removal claim is not the same as a grit rating for the liquid.

Read the exact wording

A manufacturer may state that a named product can remove marks left by a specified sanding stage when used with a particular pad and machine. That is a performance claim under defined conditions. It does not mean the liquid contains particles identical to the abrasive paper, or that every mark from that grade will be removed safely.

Sanding method, abrasive condition, contamination and scratch refinement affect the surface presented to the compound. One deep outlier can remain even when the general pattern has been corrected.

Ask for the complete system

Record the abrasive sequence, paint condition, machine, pad and compound instructions. Where sanding is part of a professional repair, verify that the refinement stage was actually completed before evaluating the liquid.

Do not substitute an internet grit comparison chart for the manufacturer’s current procedure. A rotary wool combination and a DA foam combination can produce different results with the same bottle.

Compare outcomes directly

For a workshop trial, use comparable prepared areas and inspect after suitable residue removal. Record whether the target sanding pattern is removed from view, whether isolated marks remain and what refinement is needed afterward.

Avoid translating a brand’s cut scale into another brand’s numbers without a shared test method. A high cut score is a position within a product range, not a universal physical unit.

The useful purchasing question is: ‘Can this specified system produce our required finish from this verified starting condition?’ That question can be tested. ‘What grit is this compound?’ often invites a simple number that conceals the process variables and the paint’s limits.

Related polishing guides

• Sanding-Mark Removal Claims on Compound: How to Read Them
• Heavy Cut After Sanding: Diagnose One Remaining Coarse Scratch
• Compound Drying, Abrasive Breakdown and Paint Removal Are Different Events
• Car Polish and Compound: A Complete Selection Guide

Technical references

Manufacturer sources describe their own products and methods. The workshop decision framework above is editorial guidance; follow the current instructions for the exact paint, liquid, pad and machine you use.

• Koch-Chemie: Heavy Cut H9.02 product-specific instructions

For current NANOLAB product instructions and compatibility, visit product documentation or contact the technical team.