Car Body Filler: the essential product for auto repair and painting
Car body filler is a key product in the repair and refinishing process. With its thick, malleable texture, available as a paste or cream, it fills dents and surface imperfections, levelling panels before painting.
Where to buy high-quality car body filler at the best price?
Get the best car body filler for auto repair at unbeatable prices on KMK Refinish. By purchasing directly from the manufacturer, professional body shops can optimise costs without compromising on quality.
👉 Click here to explore our full range of professional car body fillers
Which car body filler should you use?
The most common product in body shops is the 2K polyester body filler, made of polyester resin and mineral fillers. It requires a peroxide hardener to activate, with a typical mixing ratio of 2–3% by weight.
There are different types of body filler, each designed for specific applications. Below are the main types, with guidance to help your choice.
Universal Polyester Body Filler
This is the most popular choice among professionals thanks to its versatility, flexibility, non-porous texture, and excellent adhesion to various surfaces.
✅ Recommended product: KMK 1001 Soft Putty
Lightweight or Low-Density Filler
A lightweight, flexible filler with low specific weight. Easy to spread and ideal for all types of bodywork. Key features include easy sanding, strong adhesion to multiple substrates, and no added weight—perfect where lightness matters.
✅ Recommended product: KMK 1001 Light Putty
High-Build Polyester Body Filler
A flexible, high-build filler with low density, used when a thick layer is required. It is non-porous, easy to apply, sands smoothly, and provides excellent adhesion.
✅ Recommended product: KMK 12750 Extrasoft Putty – ideal for small touch-ups.
Aluminium-Reinforced Body Filler
This flexible filler offers exceptional anti-corrosion properties. It contains mineral fillers and high percentages of aluminium particles, which ensure:
- Strong adhesion
- High hardness
- Heat resistance
- Resistance to water, fuels, and lubricants
It adheres perfectly to aluminium, steel, and fibreglass, and is easy to spread and sand.
✅ Recommended products: KMK 1301 Aluminium Putty
Fibreglass Body Filler
Made with polyester resin and fibreglass reinforcement, this filler provides strength and hardness. It is ideal for repairing large damages, holes, or major imperfections and is particularly useful on fibreglass panels.
✅ Recommended product: KMK 1601 Vetroresina Putty
Plastic Body Filler
A flexible polyester filler designed specifically for plastics. It offers excellent shock absorption, elasticity, and flexibility, making it ideal for surfaces exposed to movement, bending, and vibrations.
✅ Recommended product: KMK 15500 Putty for plastic
How to mix 2K car body filler (step by step)
- Measure filler; add 2–3% hardener by weight.
- Mix until colour is uniform; avoid trapping air.
- Apply thin layers; allow to cure; sand progressively.
Visit our KMK Refinish YouTube channel to watch video tutorials and discover the correct application techniques for each type of body filler.