There are several ways to prep a car for a new paint job. Sanding the existing paint down is an option, as is media-blasting the body. But the most complete and thorough way to ensure a perfect coat of new paint is to have the car stripped down to bare metal and acid-dipped.
The process of acid dipping is exactly what it sounds like. After a car is disassembled right down to the bare chassis, it's suspended by a set of ropes and lowered in a vat of acid, where it's chemically stripped of everything that's not metal, whether that's paint, rubber, glue, or filler.
3S Chemicals LLC of Nanty-Glo, Pennsylvania uses a three-step process to ensure there's absolutely nothing left before a car goes to paint. First, the car is dipped in an alkaline degreaser and paint remover to remove any residue and paint. Then, it goes into a food-safe rust remover to eliminate any rust on the body, leaving only good, usable metal. After that, it's dipped into a rust inhibitor fluid to ensure the body won't rust further in the time between this process and when the body is painted.
The Minute_of_Dangle YouTube channel shows the entire process on a 1972 Porsche 911, giving us an inside look at all of the stuff one might run into when acid-dipping a car. This car was pretty rough around the edges, with several layers of old paint, a gruesome boomerang-shaped hole in the roof, and some nasty rust hiding beneath the fiberglass that shapes the rear seats.
It's incredibly satisfying to see the layers of paint simply fall away with a pressure washer, sometimes coming off in gigantic chunks. Things like seam-sealer and that fiberglass required several dips into the acid to fully remove. According to the video's description, the entire process takes about six weeks, as 3S Chemicals uses environmentally safe products to perform these dips.
