Rustproofing

Rustproofing is the prevention or delay of rusting of iron and steel objects, or the permanent protection against corrosion. Typically the protection is achieved by a process of surface finishing or treatment. Depending on mechanical wear or environmental conditions, the degradation may not be stopped completely, unless the process is periodically repeated. The term is particularly used in the automobile industry.

Vehicle Rustproofing Application

Factory

In the factory, car bodies are protected with specially chemical formulations, typically phosphate conversion coatings. Some firms galvanize part or all of their car bodies before the primer coat of paint is applied. If a car is body-on-frame, then the frame (chassis) and its attachments must also be rustproofed. Paint is the final part of the rustproofing barrier between the body shell (apart from on the underside) and the atmosphere. On the underside, an underseal rubberized or PVC-based coating is sprayed on. These products will be breached eventually and can lead to unseen corrosion that spreads underneath the underseal. Old 1960s and 1970s rubberized underseal can become brittle on older cars and is particularly liable to this.