A Car body filler is a specially formulated compound used to repair dents, chips, or surface damage on your vehicle. It’s an important part of modern car body repairs that helps technicians restore panels to their original smooth shape before the paintwork.
Today, cars are made of aluminium, high-strength steel, or composites. All these materials require advanced repair techniques, and the filler is an essential part of the repair process when the panel has lost its original shape and needs paintwork.
In this article, we will discuss when a car body filler is required, how it is used in repairs, and its different types. Whether your car has been damaged in an accident or you simply want to understand the filling process at your local car body shop in London, this article has everything you are looking for.
Article Highlights
This article offers information about:
- Car body filler uses
- Different types of fillers
- How it’s used in the repair process
When is Car Body Filler Used?
Car body filler is used when other techniques like paintless dent removal (PDR) are ineffective. Here are some typical applications of the car body filler:
- When the dent is too deep and simply pushing or pulling it is not enough, the technician will use filler to create an even surface before applying paint.
- When the paint chips away, the exposed metal surface can become vulnerable to rusting and corrosion. It can be filled and protected using body filler followed by primer and paint.
- Filler helps restore badly distorted car doors, wings, bonnets, and bumpers that cannot be reshaped easily.
Types of Car Body Fillers
Different forms of car body fillers are available for different types of damage and surfaces. Here are some of the most commonly used body fillers and their applications:
Standard Filler
Standard fillers are usually used for medium to larger dents and surface issues on steel or aluminium panels. They’re easy to mix and apply, plus sanding them down isn’t difficult either. They are ideal for repairs that don’t involve any heavy reinforcements of the original structure.
Lightweight Filler
Lightweight filler contains microspheres or other low-density components best suited for small dents, dings, and scuffs. Technicians prefer it because of its smooth finish and easy workability. It’s ideal for jobs where multiple layers of filler application are not required.
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Fibreglass-Reinforced Filler
Fibreglass-reinforced filler contains chopped strands of fibreglass. It provides higher strength and is usually used for structural or semi-structural repairs. It is applied to the car body parts that can flex slightly such as bumpers and sills. It’s also extremely resistant to moisture and can be used in areas prone to rust. This type of filler is generally harder to sand compared to standard fillers and often requires an additional skim of lightweight filler for a smooth finish.
Aluminum Filler
This filler has actual metallic particles in its composition, enhancing its strength and allowing it to withstand heat better. It is commonly used on luxury or classic cars on spots that are constantly exposed to heat, such as engine bays. Aluminium filler helps create a solid surface that doesn’t shrink or crack over time. However, it’s a little expensive and can be difficult to sand down, but the end result is worth it.
Glazing Putty
Glazing putty is primarily used as a finishing filler before priming. It has been specially designed to cover even the tiniest of imperfections such as hairline scratches, sanding marks, or air pockets appearing from other fillers. It can be applied in thin coats for easy spreading over larger areas or complex details. Unlike other fillers, it’s purely used for light touch-ups to create a smooth surface for paint application.
How is the Car Body Filler Used in Repairs?
Car body filler is part of a thorough repair process, involving the following steps:
1. Assessment of Damage and Panel Preparation
Before applying filler, the technicians assess the damaged area. They look for rust, sharp edges, or cracks and decide which filler to use. The panel is then prepared by cleaning and sanding. It is to remove dirt, grease, and even any old paint or corrosion. This allows the filler to bond properly onto a smooth surface.
2. Mixing the Filler
Body filler is then mixed with a hardener on a flat, non-porous surface. As soon as the hardener is added, the mixture’s colour changes slightly, indicating that it is ready for application. This is usually done at the last moment, as the mixture starts to harden quickly.
3. Application of the Filler
An applicator or a plastic spreader is used to apply the filler. This is done in different layers and the dents are usually overfilled slightly to allow sanding for a smooth finish.
4. Sanding and Shaping
After the application, the panel is left to dry, and the filler is allowed to harden. Once hardened, the filler is sanded down using coarse sandpaper to shape it. A finer grit is then used to match the smoothness of the surrounding panel.
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5. Priming
The primer prepares the surface for paint and seals the filler from moisture and corrosion. It must be allowed to dry out properly so the paint can bond with the primer.
6. Painting and Finishing
After the primer surface is dry, the first layer of car colour-matching paint is sprayed. After the first layer dries, another layer of paint is sprayed. 3 layers of paint are usually enough to get the best results.
7. Clear Coating
To seal of the paint, a clear coat layer is usually sprayed over the painted surface. It will stick to the paint layer beneath and provide a clear, glossy finish. It also provides protection against minor scratches, UV rays, and other harsh weather conditions.
8. Polishing and Compounding
After the clear coat is totally dried and cured, the whole car body is usually compounded and polished. This process helps to level out the surface, remove any fine imperfections in the paint, and bring out a uniform shine and gloss across all the panels. It blends the painted panel with the rest of the car’s body.
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Final Thoughts
Body filler is an essential part of car body repairs as it enables technicians to restore the shape of a vehicle even after severe damage. It’s usually used to smooth dents, rebuild chipped edges, or level out scratched panels.
If your car also has dents or surface damage that requires attention, it’s best to go to an expert car body repair specialist who knows how to use car body fillers correctly to give your vehicle a long-lasting and flawless finish.
Frequently Asked Questions
It’s used to fill dents, deep scratches, and minor holes to create an even surface before the paint is applied.
Using body filler over paint isn’t durable. It’s usually applied on the bare metal beneath the paint for best results.
Since filler is applied between the metal and the paint, it can last as long as the paint itself with proper care.
Need Expert Car Body Repair Services in London?
At AVX, we use top-grade fillers and advanced paint-matching techniques to get your car looking as good as new. From insurance-approved automobile repair to minor cosmetic tweaks, we handle it all with best results guaranteed. Contact us today to get a free quote.
