Underbody Coating

Under-body coating:- The Underbody coating (UBC) is defind as a thick resilient coating applied to the underbody or chassis of an automobile to protect against impact damage from small stones, which would rapidly chip ordinary paint, allowing rusting to begin.

UNDERBODY COATING AND ITS PURPOSES:

Modern automotive coating methods consist of five main steps. They include the following:

• Pretreatment: removes and cleans excess metal and forms an appropriate surface structure enabling bonding of a corrosion protection layer.
• The next step is electrodeposition (ED) of the anti-corrosion or rust prevention layer.
• A sealer like Poly Vinyl Chloride (PVC) is applied for anti-corrosion, elimination of water leaks, and minimization of chipping and vibrational noise.
• A primer is then applied to promote adhesion between the surface and the basecoat; it also imparts a smoother surface for subsequent layers and has anti-chipping properties.
• Finally, the topcoats that include a basecoat and clearcoat are applied; they provide
  surface properties that are sought after, including color, appearance, gloss, smoothness, and weather resistance.

The areas of an automobile depicted in Figure 1 show where these five steps of coating and other additional coatings are used. As can be realized when examining this figure, a significant number of specific coatings and materials are needed in addition to the above-listed steps to manufacture a salable automobile.

This treatment is designed to provide long-term protection from rust to the under chassis. It protects the underbody substrates from:

• Environmental conditions
• Impacts
• Dampens sound and vibration
• Insulates against cold and heat
• Protects against Corrosion
• Seals off seams
• Hides welds, repairs & bodywork with spray

Rubberized Underbody Coating

Wax Based Underbody Coating

Asphalt Based Automotive Undercoating

Polyurethane Underbody Coating

pros and cons of under body coating:-

The underbody coating that is most commonly used on cars in India and supplied by companies such as 3M is a thick, rubberized paint that forms a 2-3 mm thick coating all along the underside of the car when sprayed on. You also get a thinner clear coat underbody coating which is like a lacquer that coats the entire underside of the car. Some even inject rust-preventive coating material into crevices such as the bottom of doors and door sills, to protect them from rust.

Some car manufacturers already offer some underbody coating straight out of the factory which is usually sprayed inside the wheel arches and under the floor board of the car.

Here are some benefits of underbody coating

Rust Prevention
Ideally any additional underbody coating should be applied when the car is brand new and clean. Car manufacturers use thick paints and sealants for the underbody, but adding an underbody coat especially in coastal cities is useful. Salt water tends to corrode cars really badly.

On bad roads, flying stones and pebbles can chip off the original underbody coating and leave the metal exposed. Using an aftermarket underbody coating offer extra protection.

Sound insulation

The thicker underbody coatings used on cars also act as effective sound dampeners. They can reduce road noise and tyre noise and make the cabin seem quieter – due to the sound absorptive nature of rubberized paints.

Easy maintenance

A uniform black underbody coating gives a car a clean look. It also makes the car easier to maintain by just hosing the underside down. You can be confident that slush build up won’t lead to rusting easily. Most underbody coats these days come with a five-year warranty, which is the lifetime of such a coating.

Here are some of the downsides to underbody coating:

High cost

Cost of underbody coating has come down, but is still expensive. This is because underbody coating offered by a car dealer is one way in which they make money off the customer.

Risk of damage during application

Care must be taken while applying underbody coating. This thick rubberized paint if not applied properly, can get into moving mechanical parts and cause premature failure – such as into the U-joint or CV joints in a cars propeller shaft or drive shafts. They can also hinder smooth movement of suspension components, if applied incorrectly. And there’s also the risk of overspray on to the car’s paint finish on the lower edges of the car.

The device which is use to measure the thickness of underbody coating is

Dry film thickness meter - Elcometer

The device which is used to understand the composition of the coating has is

NITOX XLT