Undercoat RemovalFred Eickelmann
Automobile manufactures used undercoat to protect the underside, and most of the time that's exactly what it did. We have found that where there is undercoat, the metal is in good condition. However, the removal of undercoat on vehicles can be a difficult task and proves to be labor intensive. The following methods are ways to remove undercoat.
Chemical Stripper - There are several types on the market. They work well, are slow and messy, but certainly something you can do at home. You can also have your body dipped, just beware it’s often difficult to get all the chemical out of the tight spaces in the body like pinch welds, and any chemical residue can ruin a new paint job.
Abrasive Media Blasting - A mineral-based media not only strips away the undercoat, but will also prepare the surface for proper adhesion of primers.
Torch and Putty Knife - When the undercoat is extremely thick, this is the best method to use. We use a Bernzomatic propane torch to heat the undercoat to a softened state, then scrape it off. Yes, it's messy and it doesn't smell good...a well ventilated work area is a must.