Specialized Painting Processes - Undercoating
1. Undercoating
Front floor, rear floor and inside the front and rear wheel houses of mass produced vehicles are undercoated (mineral- based vinyl chloride) in order to protect those parts from chipping damage caused by flying stones etc. Though the thickness of the paint layer differs depending upon the parts, it is usually 0.5?1.5 mm (0.020?0.060 in).
When those parts are repaired or replaced with a new one, use a commercially available undercoating (Nox-rust 409- 20s, Solton 1000s Hard wax etc.).
NOTE: Check the paint manufacturers’ instructions for their product specifications when using undercoat agent.
Refer to the model specific body repair manual for details about undercoating locations.


Coating Processes
1.
Mask interface surfaces of the assembly parts including dampers, sub frame, etc. Also all power train and exhaust related parts to avoid overspray when necessary.
2.
Clean up the area to apply undercoating and wipe off oily residue with degreaser.
3.
Apply undercoating paint to the under floor and inside the wheel houses.
Make sure the paint layer to be 1 mm (0.039 in) or thicker on the welded joints and each floor joint areas as well as the wheel houses.
4.
Dry the undercoat.
NOTE: Always refer to the paint manufactures' instructions for the appropriate drying time.
5.
Give a top coat.




Actions for Environmental Concerns

By eliminating the use of PVC (polyvinyl chloride) for interior plastic parts and body undercoating, the chloride concentration ratio in the shredder dust at recycling is reduced to 1% or less. Recently, the traditional undercoat (mineral-based vinyl chloride) for mass produced vehicles has been replaced with a foam type undercoat. For some models, insulation undercoating is applied to the side sills and rear wheel houses to enhance the noise insulation performance and reduce the number of parts.

NOTE: As the foam type is very soft, be careful not to damage the paint layer while removing and installing the surrounding parts. The paint layer of foam type is thick, thus apply thicker undercoat when repairing with a commercially available undercoating.

Foam Type Undercoat and Insulation Undercoat (Example)