Automotive Sanding Grit Guide for Car Repairs

Choose sanding grit for the repair stage

Choosing automotive sanding grit starts with two questions: what material are you working on, and what coating will go over it? Preparing a substrate for filler, shaping cured filler and finishing primer are different jobs. Use the technical data sheet for the exact filler or coating rather than applying one grit sequence to every repair.

Before ordering abrasives, write down the manufacturer’s preparation grit, initial sanding grit, final sanding grit and permitted wet or dry method. Also check the next coating’s requirements. A filler sanding recommendation is not automatically the final finish required before basecoat.

A product-specific example: U-POL EASY 2

The published U-POL EASY2/3L technical data sheet, version 2.0 distinguishes these stages:

• Initial sanding of the filler: P80 to P120.
• Final sanding of the filler: P180 to P240.

These are that product’s instructions, not a universal sanding chart. Check the current data sheet for your product and substrate before starting, including its preparation, curing and over-painting requirements. Our body filler sanding guide explains how this stage fits into a repair.

Match the abrasive format to your equipment

The right grit is only part of the choice. The abrasive also needs to fit the tool or sanding block. In our Starcke abrasives range, compare:

• Discs: check the diameter, backing and hole pattern. A 75 mm no-hole grip disc is a different format from a 150 mm disc; the range also includes different perforation patterns.
• Strips and sheets: check the working dimensions and attachment method against your block or tool, then choose the required grit.
• File belts: match both belt width and length to the machine specification.
• Wet-and-dry sheets: confirm that both the abrasive and the material being sanded permit your intended method. Do not assume every abrasive can be used wet.

For repeat work, compare the 50-pack abrasive strips with the 100-pack options. Check the selected variant and pack quantity, not just the first price shown.

Check the surface before moving to the next coating

Follow the filler or primer maker’s sanding stages and curing instructions. Guide coat can help reveal high and low areas during the sanding process; U-POL also recommends it in the EASY 2 data sheet. Read our guide coat guide for the role of this check.

Before colour, use the primer and paint system’s specified final preparation. If the surface is not ready, correct it according to that system’s instructions rather than covering it with another coating. Follow the relevant safety data sheets and equipment instructions for dust control and personal protection.

A sanding-supplies ordering checklist

• Exact filler, primer or paint system and its current technical data sheet.
• Required grit for this stage, including the finish needed by the next coating.
• Disc diameter, strip dimensions or belt dimensions.
• Backing, attachment and hole pattern.
• Approved wet or dry use.
• Selected variant and pack size.

Browse Starcke sanding discs, strips and sheets or read the car panel preparation guide to plan the surrounding repair stages.