Underbody Coating
UNDERBODY COATING
Underbody coating is usually a dense cladding (often based on rubber) applied uniformly to the undercarriage of the automobile. It is normally sprayed or painted on when the car is just out of the dealership and is clean. But even if you are getting the undercoating applied after a couple of years, it’s fine too. This is because it can prevent further damage to the undercarriage. The main purpose of undercoating is to check rust especially in the body components like frame rails along with other exposed metal parts. Underbody coating can also reduce wear and tear.
The above given photo of the underbody shows, before and after providing the underbody coating
Modern Automotive Coating Method
The coating methods consists of five main steps. They include the following:
- Pre-treatment
- Electrodeposition
- Rust-Proof Materials: Sealer/PVC
- Primer
- Topcoat
Pre-treatment
The first sequence in preparing the BIW for subsequent coating is pre-treatment. Pre-treatment removes & clean excess metal & forms an appropriate surface structure enabling bonding of a corrosion protection layer. It consists of cleaning the body surface to remove remaining oils from the staming process & welding residues through three primary liquid dip processes of degreasing, conditioning, & phosphating.
Electrodeposition
E-coating involves dipping automobile bodies into the coating solution & passing an electric current through the body & the liquid ED paint solution. Because of the charged nature of this coating process, the ED paint penetrates into places a spray would not reach.
Rust-Proof Materials: Sealer/PVC
The third step is underbody coating & seam sealing using PVC
Primer
The fourth coating step is the primer. It can be water-borne, solvent-borne, or a powder. The primer fills & smoothes minor imperfections & scratches that may be created during prior steps & by the intermediate sanding or grinding used to remove small imperfections. It also provides additional protection against corrosion & maximizes adhesion between it & the E-coat & basecoat; thereby, the primer increases paint durability.
Topcoat
The final step in the body coating process is to apply the topcoat, which consists of two layers the basecoat & clearcoat.
Basecoat: It contains the primary colouring pigments.
Clearcoat: The final coating on an automobile surface is the clearcoat; it provides durability, environmental etch, & scratch resistance to the overall coating.
Types Of Under Coating
Rubberized Underbody Coating
This is generally thought of as the best underbody coating for your car. It preserves the underbody well, protecting it from scratches. Applying this to the undercarriage is not much of a hassle either.
Wax Based Underbody Coating
This – more or less – ephemeral undercoating will wear away in a few months’ time. On the upside, wax-based undercoating puts up a big fight against moisture. It is also the most affordable option out there.
Asphalt Based Automotive Undercoating
Best suited for lorries, trucks and large vehicles this provides a greater degree of protection compared to rubber-based coatings. However, asphalt-based coatings contain little amounts of rubber for sound-insulation purposes. The process of applying this coating is a bit time-consuming though.
Polyurethane Underbody Coating
This coating closes up splits and fractures on the underbody of the vehicle. It offers up good protection against corrosion and also bonds with the metal. Unlike in the case of asphalt-based coating, you can paint over the polyurethane coating.
Pros And Cons
Pros
- Prolong Car’s Life
- Fights Rust
- Absorbs Noise
- Reinforcement
Cons
- A used vehicle may already have residue on the bottom of the car or even have spots of rust and corrosion. Undercoating will not help you if corrosion already exists and the corrosion needs to be removed first before it can be applied, which can be expensive for you.