What You’ll Need

• Resin Fibreglass Repair Kit – Complete Polyester Resin and Hardener Set – for structural repairs with fibreglass and polyester resin
• CROP 2K Fiberglass Putty – 750 ml + Hardener – for filling cracks, dents, and shaping repairs
• “Carbon Resin” – Epoxy Resin for Carbon Fiber & Fiberglass Coating – if using carbon fibre or advanced fibreglass for a glossy, durable finish
• Protective gloves, mask and eye protection
• Sandpaper or sanding block (preferably multiple grades)
• Mixing containers and applicator brushes
• A clean, dust-free work area

Essential tools and PPE for safe resin work

Gather tools and protective gear before you start. Make sure you have gloves, eye protection, and a mask ready, along with all mixing and application tools. This will help keep the process smooth and safe from start to finish.

Step 1: Prepare and Clean the Car Body

Thoroughly clean and degrease the car body before starting any resin application. Wash the repair area with a suitable automotive cleaner and degreaser, removing all traces of dirt, oil, wax, and contaminants. Rinse and allow to dry completely, ensuring that no moisture is trapped beneath future layers.

Mask off any areas not being repaired to avoid accidental resin contact. Effective preparation prevents adhesion issues later in the process.

Step 2: Sand and Prepare the Surface

Sand and prepare the area for maximum adhesion. For small cracks or dents, use coarse sandpaper (around P80–P120 grit) to roughen the paint and remove any corrosion or flaking material. Feather the edges around the repair to avoid future lifting.

Wipe the sanded area with a lint-free cloth and degreaser to remove dust. This promotes a strong mechanical bond for the resin layer.

Step 3: Apply the Resin and Reinforcement Materials

Apply resin and reinforcement materials methodically. For structural repairs or reinforcing larger cracks and holes, use the Resin Fibreglass Repair Kit – Complete Polyester Resin and Hardener Set. Cut the fibreglass mat to fit the repair zone and mix the resin and hardener following the kit’s ratio instructions. Apply a layer of resin to the area, lay the fibreglass mat over the top, and saturate it with more resin using a brush. Remove trapped air bubbles by gently dabbing or rolling.

For shallow dents or surface smoothing, mix and apply CROP 2K Fiberglass Putty – 750 ml + Hardener, pressing it into cracks and imperfections. Shape while soft, then allow it to cure as specified in the product’s instructions.

If working with carbon fibre or aiming for a particularly high-gloss, resilient finish, consider “Carbon Resin” – Epoxy Resin for Carbon Fiber & Fiberglass Coating, ensuring you achieve even wet-out and professional results for composite applications.

Step 4: Let the Resin Cure and Finish the Surface

Allow full curing time before finishing. Make sure the resin or putty is completely set and hardened as per manufacturer guidelines—this may range from several hours to overnight depending on temperature and the specific product.

Once cured, sand once more to smooth the repair and blend it seamlessly with the surrounding body. Start with a coarse grit and move to finer grades for a smooth, even surface. Wipe clean again and, if needed, apply primer before painting to match the car’s finish.

Tips and Common Mistakes

Work in a ventilated, dust-free environment for best results. Always wear gloves and appropriate eye protection when handling resins and chemicals. Carefully follow each product’s mixing and curing instructions; inaccurate ratios or inadequate curing lead to weak repairs.

Avoid applying resin or putty to damp, contaminated, or poorly sanded surfaces, as this reduces adhesion. Don’t rush sanding between layers—the quality of your preparation directly affects the longevity and aesthetics of the repair.

Expert techniques for a flawless car body finish

Patience is key. For the best appearance and long-lasting repairs, allow each layer to cure fully, sand thoroughly, and always clean between stages. Professional results are all in the details of each careful step.