Underbody Coating

Underbody Coating

A vehicle's underbody is subject to wear and tear caused by elements such as stones, potholes, muddy water. To prevent this from happening a coating is applied to the underside of the car body known as underbody coating. This shields the underbody from rust and the debris coming off-road.

Pre-treatment consists of cleaning the body surface to remove remaining oils from the stamping process and welding residues through three primary liquid dip processes of degreasing, conditioning, and phosphating. The metal underbody and frames of automobiles are coated to prevent corrosion, whereas other areas like the roof are not rust-proofed.

Secondly, electrodeposition coat or E-coat provides rust and corrosion protection. E-coating involves dipping automobile bodies into the coating solution and passing an electric current through the body and the liquid ED paint solution. Because of the charged nature of this coating process, the ED paint penetrates places a spray would not reach. During operation, a mixture of resin, binder, and a paste containing the pigments is fed into the electrodeposition tank.

The third step is underbody coating (UBC) and seam sealing using PVC (Polyvinyl Chloride) and urethane.

The final step in the body coating process is to apply the topcoat, which consists of two layers—the basecoat and clearcoat. The basecoat contains the primary colouring pigment, and the clearcoat provides a protective coating against environmental effects, corrosion, and UV light degradation, promotes unmatched colour retention, and provides a smooth, unblemished, and even finish.

Advantages

• The underbody coating provides anti-corrosion and chipping protection; typically, it is accomplished using robots equipped with airless sprayers.
• Sound Dampening – Some of the underbody coating solutions provide a layer of insulation which acts as sound dampeners. However, the coating will not result in pure sound isolation.
• Increase in Lifespan – it increases the longevity of the car and aids in increasing the resale value of the car.

Limitations

• Weight Addition – The coating adds weight to the car, though a very insignificant can cause small changes in the fuel economy of the car.
• Economic Aspect – The undercoating is quite expensive. The material, as well as the labour cost, add a lot of expense. The annual maintenance charges of the vehicle can also increase as some undercoating need to be reapplied after a year.
• Tricky Application –They do require some experience and if the process is done wrong, it can cause an obstruction in some of the moving parts. If applied to some moving parts, the mobility of those parts can get affected disturbing the clearance of those parts.

Types of Underbody Coating

Wax or Paraffin – Based undercoating:

The wax is not very adhesive on a metal surface and its main advantage is that it seeps quickly into cracks and seams, and offers moderate protective properties against moisture.

Rubberized undercoating:

It cushions surfaces against moisture, rust, dings, and dents.

Polyurethane undercoating:

It works by sealing up cracks and seams. The compound displaces salt and moisture and protects the unoxidized metal from rust.

Asphalt – based undercoating:

It offers extra protection against chips and moisture but is not paintable