Preslee Jeffers owns Action Metal Stripping in Hubbard, Ore., and he took some time to chat with us about stripping cars for restoration:
PR: Can you give us a rundown on the stripping process?
PJ: First of all, you have to tear the car down -take the doors off, take the hood off, because you’ll get a better clean that way. Take out all the upholstery, glass, chrome and wiring. Take all the aluminum off, because the caustic used for dipping will dissolve aluminum. You have to tear a car all the way down to the shell,
PR: So absolutely everything has to come off?
PJ: Yes. Be sure to take the VIN tag off, because those are usually aluminum and you don’t want to lose that. You may want to engrave the VIN on the body, if you’re concerned about it.
PR: What happens once someone brings you the shell?
PJ: Then it depends on what you want. Some people like chemical stripping and some people don’t. The downside of chemical stripping is that the chemical can get trapped in the pinch welds and leak out 6 months to a year later. The chemical dries up, but when moisture gets to it, it reactivates. A lot of people will bend the pinch welds back so they can clean them out, or they’ll remove the skins from the structures entirely and reinstall them afterwards.
PR: What’s involved in chemical stripping?
PJ: The dip solution is a caustic soda. It’s an alkaline called sodium hydroxide. We heat it and it removes paint, grease, oil, and undercoatings, but it won’t remove rust. So you have to put the car in a bath of muriatic acid to remove the rust, then you pull it out of the acid, steam clean it, and put it back in the caustic to neutralize the acid.
PR: But chemical dipping doesn’t work on aluminum, right?
PJ: If you put aluminum in caustic dip, it’s guaranteed not to be there when you’re done. Aluminum is a very soft material. We have a chemical strictly for aluminum, called methylene chloride. It’s not a caustic and it’s not an acid. It’s a solvent-based product that removes paint, powder coat, grease, whatever. Some cars are particular problems. For example, on Austin-Healeys the skins are aluminum, but the frames are steel, so it’s a challenge because the methylene chloride will make steel rust.
PR: Tell me about media blasting.
PJ: With media blasting, we use plastic, glass, walnut shell, or sand. Plastic works great for removing the paint, but won’t remove rust at all. Glass will remove the paint and surface rust. Sand will remove everything, but it’s very aggressive and will have a chance of warping panels. Sand’s the worst.
PR: But there are parts of cars that shouldn’t be blasted, right?
PJ: The metal skins on doors and hoods are thin, and there’s not much bracing behind them. They’ll warp if you blast them. We don’t use sand on surface body panels, roofs, hoods, or trunk lids. We dip the doors, hood, fenders, then go over it with a really light blast afterwards. For a chassis, we’ll sandblast it. We’ll also use sand for brakes, suspension pieces, and other parts that are made of cast steel.
PR: Which process is better?
PJ: People like chemical stripping because it leaves a nice a finish, and there’s very little metal loss. But they don’t like chemical being trapped in pinch welds and inside of box sections like rocker panels. But with any type of abrasive blasting, there’s a dust issue. There’s always a little bit of material left in gaps, spaces, and box sections. It’s up to the customer which one they prefer.
PR: What should someone do with a car once you’ve stripped it?
PJ: You need to seal the metal immediately after stripping. It’s not so bad in the summertime when it’s dry, but if it’s wet, you need to get it to the body and paint shop ideally the same day. We get on the phone with the customer as we’re finishing up, so they can get the car right in to be primed, sealed, or painted in some manner.
PR: How much is this likely to cost?
PJ: That depends on the size of the job, really. People should always compare prices between vendors. When we’re blasting, we charge by the hour and we know how long it takes to blast a particular size of car. Chemical stripping is always the most expensive. To get a body chemical-dipped, you’ll pay 2 to 3 times as much as to blast it.
PR: How should someone evaluate a blasting or stripping shop?
PJ: In our business, it goes by reputation. Car guys can join a club if they don’t know people who have done restorations. If someone is talking from experience, they’ll be able to tell you where to go. If you don’t have that, ask a business for references.
PR: Anything else to add?
PJ: Always get your estimate in writing, because sometimes you go to pick up the car and it won’t be the same price as when you dropped it off. You don’t want to be surprised at the end.
