Under body coating in modern cars
External influence like hot and cold weather, rainy water and salt water are accelerating corrosion on car body’s exposed parts and a chips or gravel on the road delaminate the film from the substrate to spot. This spot is exposed to external environment and start to corrode, this reducing the vehicle life. To save vehicle\'s under body parts from corrosion and extend it\'s life under body coating (UBC) and seam sealing is applied on vehicle’s chassis / frame.
Main purposes of the UBC is to provide protection against corrosion, Provide resistance against chipping, preventing the entering of water and dust and this also serve as noise proofing agent. This process is accomplished using robots equipped with airless sprayer. Under body coating is a thickened rubberised coat mainly of PVC (polyvinyl chloride) and urethane. Thickness of this under body coating is varied from manufacturer to manufacturer and car to car, depending upon the design requirement, budget of the vehicle and market for which it is going to be sold. Below table shows purposes and type of sealants used for under body coating process.
The sealant is applied around doors, hood, trunk and front dash onto the exterior and interior of metal joints and outer area and outer area of back wheel well. Below image displays the lower door section and rocker panel location where PVC or urethanes are applied as an anti chipping protection, and shows the cross section of this layer with respect to other coatings on other body parts.
A process called dampening coat is used to impart noise proofing. Noise transferred from engine, drive train, suspension system, road noise of the tyre, and flowing air. Under body sealant reduce noise transfer into the passenger compartment.
Sometimes vehicle manufactures reduce or eliminates under body coating to reduce manufacturing cost for competitive new car sales market of an average budgeted cars. Now a day’s many aftermarket under body coating solutions are available. Car care companies like 3M are providing aftermarket solution with different types of coating based on different materials like
a) Rubberized undercoating
- Rubberized undercoating is easy to apply and offers sound cushioning as well as protection from dust, moisture and dings or dents.
b) Polyurethane undercoating
- This is done by applying polyurethane based sealant. This type of under body coating is a little bit quicker and easy to apply.
c) 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.
d) Asphalt based undercoating
- For large trucks and heavy machinery, asphalt-based undercoating provides a bit of extra durability against rocks, chips, and moisture
Some of this coating also can be done at home by means of sprays available with basic knowledge of its application.