Underbody Coating

UNDER-BODY COATING

Automotive Underbody Coatings

Underside of vehicles serves as an intermediate between metal components of a vehicle and outer environment. Underbody o
vehicles is prone to damages due to harsh environmental conditions. Coatings are applied to the underside of vehicles to protec
them against factors such as corrosion, chemicals, moisture, water damage, and chipping of the underbody. Automotiv
underbody coatings offer a protective layer to vehicles’ underside.
Most of these coatings provide chemical and corrosion resistance, along with several other properties based on different produc
formulations. Protection of underbody and wheel arches against chip damage is achieved by applying automotive underbod
coatings, which protect the metal from debris of gravel, stones, salts, etc. tossed by the road.

Coating process of a vehicle body (automotive coating process) comprises minimum five layers of paint, while the underbod
coating process comprises the first two layers in the overall coating process. These two layers provide durable protection agains
corrosion; however, damage over time requires renewal of these coatings. Automotive aftermarket service providers often provid
these services during scheduled vehicle maintenance.

Automotive underbody coatings also offer protection against humidity, moisture, and wet conditions that can seep through th
undercarriage of a vehicle through joints or cracks in the paintwork; and cause corrosion.

Elasticity of polymers used in automotive underbody coatings allows for low noise when struck by road debris compared to tha
with uncoated underbody. As a result, vibrations of vehicles are dampened and kept to a minimum.

Automotive coating process

Pre-treatment:

The first step in preparing BIW for subsequent coating is the pre-treatment process. Pre-treatment consists of cleaning the bod
surface to remove remaining oils from the stamping process and welding residues through three primary liquid dip processes o
degreasing, conditioning and phosphating. The degreasing solution is composed of alkaline salts and surfactants and can includ
caustic soda, tri-sodium phosphate, and sodium carbonate. The surfactants are types of detergents for emulsifying oils an
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 additiona
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 th
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 powde
These primers are used to improve adhesion between the E-coat and topcoat, provide chipping protection, enhance pain
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. Th
basecoat contains the primary colouring pigment and the clear coat provides a protective coating against environmental effect
corrosion, and UV light degradation promotes unmatched colour retention and provides a smooth unblemished even finish.

Types of Vehicle Undercoating

Having undercoating professionally applied to your vehicle can be expensive, but fortunately, if your budget is tight, you can do
yourself for a fraction of the price. Here are some of the various types of undercoating available.

Rubberized Undercoating

Rubberized vehicle undercoating is easy to apply and offers sound-cushioning as well as protection from dust, moisture, an dings or dents. In addition to your undercarriage, rubberized undercoating is also safe to use on wheel wells and quarter panels, and dries to soft rubbery finish that prevents further rust, damage, or moisture seeps. The coating can be painted over and, if necessary fo 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 an 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 littl bit quicker and easier to apply. Oftentimes, polyurethane undercoating will come in canisters ready to preload into an application gun. This type of sealant work
by seeping into all cracks and seams, displacing salt and moisture and oozing around rusty areas to bond with and protec
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 an applying an etching primer to bare metals before using are generally recommended.

Wax or Paraffin-Based Undercoatings

A paraffin-based undercoating will be the cheapest and quickest option available with which to protect the undercarriage of you
vehicle. However, keep in mind that it will wear off quicker than other types of undercoating and will need to be stripped an
reapplied at least once every year.
Wax-based undercoatings never truly harden. During application, they drip or flow into seams and cracks to provide protectiv
properties. They are usually available in a spray gun canister or in an aerosol can and offer at least a base protection in moderate
humid climates.

Asphalt-Based Undercoating

For standard vehicles, any of the aforementioned types of undercoating will provide sufficient protection. For large trucks an
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 NO
paintable, making it best to use only for undercarriages.

Advantages of Underboady coating

Undercoating gives an extra layer of protection against rust and corrosion, protecting your car.
Undercoating will eventually wear out, but you can get years of protection from it. Even vehicles in warmer climates gain
protection as debris is repelled and kept away from eating at the vehicle.
It can be self-applied.
It minimizes the sound from underneath the car.
It insulates the interior of the car from the extreme temperature from beneath the vehicle.
The coating does not chip away when hit by stones

Disadvantages of Underboady coating

Undercoating will not help you if corrosion already exists and the corrosion needs to be removed first before it can be
applied, which can be expensive for you.
It must be reapplied every 3 to 5 years for the best results
It adds weight to the vehicle.