Underbody Coating
UNDER BODY COATING: -
Underbody protective coatings are used to protect the vehicle chassis from external environment, to ensure the integrity and safety of cars.
The use of UBC plays a very important role in the service life of the vehicle. In general, it is required to spray such a protective coating in the manufacturing of the new car. Due to the highly competitiveness of new car sales, car producers have pressure to reduce the manufacturing cost, so that they reduce or even completely eliminate the use of under body coating where it is not to be easily seen by car owners. As a consequence, our car service life will be greatly reduced.
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.
Underbody coating purpose:
Protects Against Rust & Corrosion
Reduces NVH (Noise Vibrations Harshness) Levels
Prevents Paint Chipping
Protects Vital Components
TYPES OF UNDER BODY COATING:
Rubberized Undercoating
Rubberized vehicle undercoating is easy to apply and offers sound-cushioning as well as protection from dust, moisture, and dings or dents.
In addition to your undercarriage, rubberized undercoating is also safe to use on wheel wells and quarter panels, and dries to a soft rubbery finish that prevents further rust, damage, or moisture seeps. The coating can be painted over and, if necessary for bodywork, can be easily removed with an undercoating removal spray.
Overall, rubberized coating is generally the best option for protecting your vehicle's undercarriage, as it provides the simplest and best protective measures against rust and moisture.
Polyurethane Undercoating
The other option for undercoating your vehicle is to use a polyurethane-based sealant. This type of vehicle undercoating is a little bit quicker and easier to apply.
Oftentimes, polyurethane undercoating will come in canisters ready to preload into an application gun. This type of sealant works by seeping into all cracks and seams, displacing salt and moisture and oozing around rusty areas to bond with and protect unoxidized metal. It also sands quickly in case you'll need to perform bodywork and can be painted over.
On the flipside, this type of car undercoating generally requires a little bit more surface prep work before applying -- sanding and applying an etching primer to bare metals before using are generally recommended.
Wax or Paraffin-Based Undercoating
A paraffin-based undercoating will be the cheapest and quickest option available with which to protect the undercarriage of your vehicle. However, keep in mind that it will wear off quicker than other types of undercoating and will need to be stripped and reapplied at least once every year.
Wax-based undercoating never truly harden. During application, they drip or flow into seams and cracks to provide protective properties. They are usually available in a spray gun canister or in an aerosol can and offer at least a base protection in moderately humid climates.
Asphalt-Based Undercoating
For standard vehicles, any of the aforementioned types of undercoating will provide sufficient protection. For large trucks and heavy machinery, asphalt-based undercoating provides a bit of extra durability against rocks, chips, and moisture.
Asphalt-based undercoating generally contains a little bit of rubberized material that sets up firmly and also helps soften noise. Generally sold in five gallon containers, this type of undercoating also needs more cure time than the other three, and is NOT paintable, making it best to use only for undercarriages.
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 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 tire 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.
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 above image will give you the best definition of under body coating.
THE UNDERBODY COATING PROCESS HAS 5 STEPS:
Pre-treatment:
The first step in preparing BIW for subsequent coating is the pre-treatment process. 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 degreasing solution is composed of alkaline salts and surfactants and can include caustic soda, tri sodium phosphate, and sodium carbonate. The surfactants are types of detergents for emulsifying oils and lubricants on the BIW
Electrodeposition (ED):
The metal underbody and frames of automobiles are coated to prevent corrosion, whereas other areas like the roof are not rust proofed. When not coated to prevent corrosion, the structural metals (or other materials) are primed before applying additional coatings: The ED processes are modified as per the BIW material property. This ED coating provides rust and corrosion protection.
Rust-proof materials: Sealer/PVC
The third step is underbody coating (UBC) and seam sealing using PVC and urethane. The sealant is applied around and inside the doors, hood, trunk, and front dash and onto the exterior and interior of metal joints and outer area of the back wheel well.
Primer:
The fourth coating step is the application of a primer surface or simply primer. It can be water-borne, solvent-borne or a powder. These primers are used to improve adhesion between the E-coat and topcoat, provide chipping protection, enhance paint appearance and also be environmentally compatible with emission regulations.
Top-coat:
The final step in the body coating process is to apply the topcoat, which consists of two layers-the basecoat and clear coat. The basecoat contains the primary coloring pigment and the clear coat provides a protective coating against environmental effects, corrosion, and UV light degradation promotes unmatched color retention and provides a smooth unblemished even finish.