Underbody Coating

UNDER BODY COATING:

Under Body Coating is a process used to prevent car bodies against rust & corrossion. this process helps in protecting the body of the car from dust and moisture and any other foriegn matter and also from other factors like poor road conditions, small piceses of rocks getting thrown by the tyres, and at the mansoon seasion salt particles from water which plays an important role in damaging the under body of car.

COATING PROCESSES:

Under body coating process of a vehicle generally undergoes in the following steps:

• Pre-treatment.
• Electro deposition.
• Application of primer.

Pre-treatment:

This is the first treatment process in preparing BIW for coating, this processes removes and clean the excess metal and forms an appropriate surface structure enablling bonding of a corrosion protection layer, it removes remaining oils through primary liquid dip processes of degreasing, conditioning and phosphating.

Electro deposition:

The under-body and frames of automobiles are coated with some anti-corrosion or rust prevention agents to prevent corrosion. This ED processes are modified as per the BIW material property.

Rust-proof materials:Sealer/pvc:

In this process some sealings will be done using PVC(Poly vinyl Chloride) & Urethane. This is applied around and inside the doors, hood,trunk & front dash and for other metal joints.

Primer:

It is the application of primer surface, it can be water-borne, solvent-borne or a powder. These primers helps to improve adhesion between the e-coat and top coat, provide chipping protection, enhance paint appearance and also be environmentally compatible with the emission regulations.

Top-coat:

The Top-coat consists of two layers- basecoat and clear coat. The base coat contains the primary colouring pigment and the clear coat provides a protective coating against environmental effcts like corrosion, and UV-light degradation etc

Under body coating of a car.

Types of underbody coating:

Underbody coatings are of different types they are categorised as follows

Rubberised underbody coating:

These coatings are very easy to apply and offer sound-cushioning as well as protection fron dust, moisture and dents. the coatings are safe even to use on quarter panelsand wheel wells.

Polyurethane underbody coating:

This type of coating is quicker and easy to apply. this type of coating often comes in a canister ready to preload into application gun. This type of coating always requires surface prepation before applying.

Asphalt-based underbody coating:

This type of coating is used for sufficient protection against rock chips and moisture, this type of coating have a little bit of rubberised material that set up firmly and also helps in reduction in noise.

Wax or paraffin-based underbody coating:

This type of coating is cheapest and fastest option available in the market. but this type of coating is having a drawback that it lasts long only for one year.

Importance of Under body coating:

• It minimizes the sound from underneath the car.
• The paint doesnot effect when hit by small chips of rocks.
• Insulates the interior and exterior of the car from the extreme temperatures.