Underbody Coating

UNDERBODY COATING

Underbody coating provides long term protection from corrosion to car's underbody. It also protects parts like internal body panels, frame rails and other inner cavities that are not physically accessible but are prone to corrosion Underbody coating is a thick cladding that is placed uniformly to the car’s underside. When the automobile is fresh off the lot and spotless, it is usually sprayed or painted on. But it’s acceptable if you apply the undercoating after a couple of years. This is because it might protect the undercarriage from additional harm

MODERN AUTOMOTIVE COATING PROCESSES

1) PRETREATMENT

The first sequence in preparing the BIW for subsequent coating is pretreatment sees . Preatrament 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. Pretreament helps the primer to bond onto the metal. A phosphate treatment applies an inert layer of metal phosphate, providing resistance to corrosion spread.

2) ELETRODEPOSITION

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 chargednature of this coating process, the ED paint penetrates into places a spray would not reach. During operation, a mixture of resin, binder, & a paste containing the pigments is fed into the ED tank. The automobile body is lowered into the tank, & an electric current applied; the solution in the tank consists of 80-90% deionised water & 10-20% paint solids.The resin is the backbone of the final paint film & provides corrosion protection, durability, & toughness. Pigments are used to provide color & gloss

3) RUST-PROOF MATERIALS: SEALER/PVC

Displays the lower door sections & rocker panel locations where PVC or urethanes are applied as an anti-chipping protection, & shows the cross section of this layer with respect to the other coatings on the body parts. During this third step, it is also typical to apply a soft tip primer coat that improves the chipping resistance . This layer is applied to the front edge of the hood , which is an area prone to chipping shock, using a high elastic resin that resides between the ED & primer coats

4) PRIMER

It also provides additional protection against corrosion & maximizes adhesion between it & the E-coat & basecoat; thereby, the primer incrases paint durability. Primer coating operations in an automobile assembly plant are usually implemented in three stages: Interior coating, Exterior coating, & then cutting in an oven. Manual spray painting is used for the interior coating of the doors, engine compartment, & luggage or trunk space

5) TOPCOAT

The final step in the body coating process is to apply the topcoat, which consists of two layers the basecoat & clearcoat. As part of the topcoat, the basecoat is third layr added to the car after the primer & before the clearcoat. It imparts the automobiles color; roughly 40,000 base coat color are known today , & approximately 1000 new colors are added to this list each yearal step in the body coating process is to apply the topcoat, which consists of two layers the basecoat & clearcoat. : The final coating on an automobile surface is the clearcoa; it provides durability, environmental etch, & scratch resistance to the overall coating. It protects against damage such as fading that is caused by UV rays from the sun & imparts a gloss & depth that otherwise are as vivid.

Types of Undercoating

1. 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. 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.

2. 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. 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 undercoatings 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.

3. 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 thourgh. 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.

4. 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. 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.

Advantages of Undercoating

i. Fights Rust

It plays an important role in keeping corrosion at bay. Underbody coating can come in handy especially if you live near the sea, where there is too much humidity, and rusting is just one of those everyday things. You should also seriously consider undercoating if you reside in a place where it snows in winter.

ii Absorbs Noise

Believe it or not, very thick undercoating can soften the noises that reach the cabin. Since the undercoating is often made up of rubber it absorbs some of the rackets. The occupants of the car could spare themselves of the road noises – at least up to a certain extend.

iii Reinforcement

If your car comes with stock underbody coating, using another coating on top of it, is not going to hurt. It will offer additional reinforcement, protecting the underbody from water, road debris, gravel and small pebbles. There would also be a lesser chance for the factory coat to flake away

iv. Prolong Car’s Life

Good undercoating not only defends the underbody from corrosion but also protects the engine and transmission as well! Less rusting coupled with slower wear and tear can surely add years to the lifespan of your vehicle. There would be fewer dents, dings and scratches on the undercarriage for you to fret about.

DISADVANTAGES OF UNDERBODY COATING

Applying undercoat over rust means that although you’re stopping more moisture and airflow to the rusted area, the rusting process will still keep happening.An undercoat will slow down the corrosion rather than reverse or stop it. You should attempt to remove the rust before applying an undercoat.Your vehicle’s warranty might be voided if you opt for a third-party undercoating treatment.Some new cars already come with undercoating so adding anything else risks your warranty. Undercoating can be damaged.you can expect a hard layer of protection against debris, driving on dirty or gravel roads often means the protective layer’s integrity will be reduced over time.