Corrosion is one of a car’s most formidable enemies,

especially when it comes to older or vintage cars. Nevertheless, there are effective protective treatments available.

Corrosion is considered particularly damaging because it frequently appears in places that are invisible and difficult to penetrate.  On the underside of doors, on sills, in welding seams, on wheel arches and on the underside of the car itself.

Although your car’s bodywork appears fine, you should never ignore the condition of the underside of the car. The underbody can be severely damaged. If there is a lot of corrosion underneath your car, you may not even pass a vehicle inspection. The greatest way to protect the underbody of your car from rust is to have the joints coated and rustproofed. Unfortunately, even such a treatment is not permanent, so it is recommended to check the underbody regularly, especially if your car is far from new.

Why does the underbody get rusty?

Our cars are predominantly made up of metal components. No other material offers the same optimal characteristics and is so reasonably priced. The only disadvantage of these components is that they are made of a high percentage of metal. The metal begins to rust as a result of contact with moisture and salt. Unless the rust is noticed and removed in time it will gradually spread.

Corrosion protection is the optimal solution

An anti-corrosion treatment consists of a protective compound which, in most cases, contains bitumen that is suitable for underbody anti-corrosion treatment. Furthermore, the anti-corrosion treatment can have both vibration- and sound insulation characteristics. New cars have a layer of protection that lasts several years. The protective paste is applied extremely thinly. Thanks to the rubber-like substance from which it is made, it fills the holes caused by gravel without scratching. However, over time, the protective layer dries out. After a period of maximum eight years, you should check the condition of this layer. If cracks appear or the layer peels off, you should immediately take measures. You can always contact our service centre for this.

Corrosion protection stages

Improving to protect against rust.

To permanently protect the underbody from rust, the old layer must be removed. This should not be done on the entire surface, but only on heavily damaged areas that need to be treated. This is usually necessary on the edges of the underbody or wheel arches. The surface of the centre section of the underbody is frequently unaffected for the entire life of the vehicle.

Confide in our service team to apply a rustproofing layer or to restore the old layer.

Using a special wax whose function is to create a protective layer that prevents external substances from sticking to the bodywork, your car will be protected against corrosion from salt (in winter) and sand (in summer).

Procedure for removing rustproofing layer

There are three methods to remove old rustproofing layer from the underbody:

  • Manual removal with a scraper and steel brush
  • Scorching
  • Sandblasting

Manual scraping with a steel brush is a very difficult procedure and is particularly suited for removing old rust where other treatments would be unacceptable. The use of equipment is of little help here. Viscous bitumen very quickly clogs the rotary brushes and sandpaper. Continuous manual processing is the superior option. Using a heat gun can make the job much easier, especially in hard-to-reach areas.

Scorching is a method for experienced professionals. We strongly advise against its use.

Eventually, sandblasting is a popular method of removing the protective layer. There are two completely different alternatives to this method: abrasive and non-abrasive sandblasting.

In abrasive blasting, a granular material is blasted onto the underside of the body with compressed air. Sand is the best known method, but there are also many other blasting media available, such as baking soda, glass, plastic beads, nutshells and many more. The advantage of the sandblasting method is its guaranteed success. The protective layer is quickly and thoroughly removed from the bottom and it is a very cost-effective method. The disadvantage is the quantity of waste produced. Furthermore, due to too high pressure or incorrect choice of abrasive, undamaged areas can be affected.

The non-abrasive method is an effective alternative: instead of solid material, dry ice blasting uses frozen carbon dioxide grains which explode on the protective layer and remove it precisely. By removing the old protective layer, dry ice blasting produces no waste and is completely safe for the underbody. Another alternative is high-pressure water jetting. The disadvantage of these highly effective methods is their cost. Dry ice blasting systems are very expensive. Consequently, these options are mainly suitable for high-value vehicles such as luxury sports cars or vintage cars. The cost of dry ice blasting by a professional mechanic is quite expensive.

Rust removal

Before a new protective layer is applied, preparatory work is required, which essentially means removing all rust. A scraper and brush is most effective, even if it only removes the old rust on the surface. A grinder allows you to work deeper, but there is a risk of damaging even untouched material. The use of a rust converter is therefore recommended. The substance should be applied and left until it is fully effective. When the red rust has turned to a black, oily mass, the specialist simply removes it with a cloth.

Degreasing the surface

Just like with paintwork, the surface must first be degreased before the rust can be removed. The most suitable product for this is a product with silicone. The top coat must only be applied and removed after it has taken effect. The surface must not be treated with any other substances afterwards. The use of WD-40 or penetrating oil is not permitted. Otherwise the degreasing procedure will have to be started all over again.

All moving and heated parts must not be treated with an anti-corrosion agent. We therefore recommend that only professionals carry out all the processing steps correctly. Steering movement may be hindered by the protective coating, the substance causes a risk of fire in the exhaust system. Special attention is therefore also paid to these areas. The outside of the underbody also needs protection.

The advantages of surface and function treatments at our service centre:

  • Excellent corrosion protection and paint adhesion properties
  • Tailor-made solutions for compound metal constructions
  • Reduced energy and water consumption
  • Reducing the number of corrosion treatment steps
  • Reduction of emissions and environmental impact
  • Increased environmental sustainability
  • We offer the optimal corrosion protection from the best manufacturers
  • We control the treatment and give a lasting guarantee
  • Coating with an anti-graveling protection agent