How to use bodywork resin?

Step-by-step guide for repairing panels and surfaces

CROP 2K Fiberglass Putty – 750 ml + Hardener

Resin-based bodywork fillers offer a tough, professional option for repairing dents, cracks, and damage on vehicles, machinery, and panels. This page explains proven techniques for achieving long-lasting, smooth repairs using modern bodywork resins. Whether you are new to vehicle repairs or a seasoned DIY enthusiast, you’ll learn exactly how to get protective, paint-ready results.

"Carbon Resin" - Epoxy Resin for Carbon Fiber & Fiberglass Coating

What You’ll Need

CROP 2K Fiberglass Putty – 750 ml + Hardener – A reinforced two-component putty ideal for filling and levelling deep damage.
“Carbon Resin” – Epoxy Resin for Carbon Fiber & Fiberglass Coating – Professional-grade resin for laminating repairs with carbon or fibreglass matting.
Sandpaper (various grits, typically from coarse 80 to fine 320)
Mixing board and spatula
Clean rags and degreasing solvent
Protective gloves, safety goggles and dust mask

Key Benefits of Modern Bodywork Resins

Bodywork resins offer exceptional adhesion and repair strength, making them ideal for structural and cosmetic automotive fixes. Their fibreglass reinforcement provides added durability, while professional epoxy formulas allow repairs to blend seamlessly and last through weather and vibration.

Step 1: Prepare and Clean the Surface

Begin by assessing the damage. Remove any loose paint, rust, or old filler from the affected area using a coarse sandpaper or a suitable abrasive. Clean the surface thoroughly with a degreasing solvent to eliminate oils, dust, and contaminants that could hinder adhesion. Let the panel dry fully before proceeding.

This step is crucial for ensuring that both the resin and putty bond directly to the substrate, minimising the risk of repair failure. Attempting repairs on unclean or glossy surfaces can lead to poor adhesion and weak results.

Step 2: Mix and Apply Bodywork Putty

For filling deep cracks, dents, or cavities, mix the hardener with CROP 2K Fiberglass Putty – 750 ml + Hardener on a clean board, following the manufacturer’s recommended ratio. Use a spatula to blend until the colour is uniform and consistent.

Apply the putty by pressing it firmly into the area needing repair, building up in layers if necessary for depth. Aim for a slight overfill to allow for sanding. Smooth it with the spatula as much as possible and leave to cure as directed. Resist the temptation to hurry the drying process; efficient curing is vital for maximum strength.

Step 3: Sand and Shape the Repair

Once the putty is fully cured, begin sanding with a coarse grit (such as 80) to remove excess material and shape the surface. Continue with finer grits to achieve a level, smooth finish that follows the original panel contour.

Always wear a dust mask during sanding, and frequently check progress by touch to avoid over-sanding. The goal is to create a seamless transition between the repaired area and the surrounding bodywork, free from sharp edges or ridges.

Step 4: Laminating or Coating for Added Strength

For repairs requiring extra reinforcement—such as cracked panels, rusted sections, or areas under mechanical stress—a resin and fibreglass application follows the filler repair. Prepare fibreglass mat or carbon fibre fabric, then mix “Carbon Resin” – Epoxy Resin for Carbon Fiber & Fiberglass Coating according to the instructions.

Spread the resin onto the surface and lay the fibreglass or carbon matting into position. Use a roller or brush to thoroughly saturate the fabric, expelling any air bubbles and ensuring full impregnation. Allow to cure at room temperature before lightly sanding and moving on to priming or painting as needed.

Tips and Common Mistakes to Avoid

Wear protective gloves and a mask when handling resin and putty to prevent skin and respiratory irritation.
Do not rush curing times for either putty or resin—insufficient curing can result in weak or tacky repairs.
Sanding between stages ensures smooth finish and adhesion. Skipping grades or steps creates uneven surfaces and poor paint bonding.
Store resins and hardeners in a dry, temperature-stable environment for best shelf life and performance.
Dispose of used rags and materials safely—resin residues can pose a fire risk.

Professional Finishing for Paint-Ready Results

Taking the time to sand and shape repairs delivers the best finish. A properly prepared and filled surface ensures that primer and paint adhere without defects, giving your project a smooth, factory-quality appearance and lasting protection.