Underbody Coating

Automobile Undercoatings Mike Prusmack

Most automobiles are made from steel which can corrode easily. A car's paint is where most of a car's corrosion protection comes from.The underside of a car is not painted and needs to be covered with a durable coating which resists damage from road debris and seals it from oxidation. Corrosion is caused by iron's tendency to form chemical bonds with oxygen. This happens when there is a free flow of electrons between the two elements. Coatings create a barrier between these two substances.

There are several main types of undercoatings. They are rubberized. polyurethane, wax, and asphalt based undercoatings.Each will be listed below with its characteristics and pros & cons.

Rubberized Undercoating

• It is considered the best option for protection from rust and moisture
• It can be used on the undercarriage, wheel wells and quarter panels
• other benefits is sound barrier and protection against damage from road debris
• If bodywork is required, this undercoating can be removed easily with an undercoating removal spray.

Rubberized Undercoating

Wax Based Undercoatings

• It is the cheapest option for undercoating, but it will wear out much faster than other options.
• Wax based undercoatings flow easily into cracks and seams.
• Good for humid climates.
• Will need to be stripped once per year and reapplied.

Wax Based Undercoatings

Polyurethane Undercoating

• Requires more surface preparation before application. It needs sanding and etching primer.
• Can be sanded if bodywork and paint need to be applied
• Flows into cracks and seams, displacing moisture and salt.

Asphalt-Based Undercoating

• Contains rubberized material that cures firmly and offers more protection from road debris than the other types of undercoating.
• This type of undercoating is used for larger vehicles which require extra protection.

Applying undercoating with a spray gun.

There is very little reason to not have your new car treated with an undercoating. The type of undercoating used may be determined by climate or use of the vehicle. Warm sunny climates that are not near salty ocean air may only require a wax based undercoating. A more extreme climate with cold winters where salt brine is used to de-ice the roads and gravel dispersed to create traction in slippery conditions, may require rubberized undercoating which provides more protection than a waved base undercoating. Caution must be used when applying undercoating to an older car that has never had an undercoating. If proper surface preparation isn;t observed, there may be rust that could become trapped under the coating and continue to oxidize.

Reference: Autobody Tool Mart https://www.autobodytoolmart.com/vehicle-undercoatings