We purchased our Sprinter van from a metal-working artist who took great care of the engine/internals of the vehicle.  He fixed rust spots as they’d get problematic, but he didn’t put much into maintaining appearances. Luckily for us, rust seemed pretty minimal – just surface rust in places around the interior, doors, and undercarriage. However, when we removed the plastic paneling on the three steps (driver’s, passenger’s, and sliding door), we found that they were completely covered in rust. One of the steps had actually rusted with a hole straight through to the ground. When we removed the floormat between the driver’s seat and passenger’s seat we were dismayed to also find the area completely covered with rust because of a metal bar he had placed to fill in a gap in the floorboard. This resulted in contact rust from the two dissimilar metals.

Realizing that rust is the beginning of the end for most vehicles, and since Sprinters are notorious for being rust-buckets, we decided to remove every bit that we could and eliminate the possibility of it ever coming back.  This is our process.

Materials

(2)  Rust-Oleum Rust Reformer Spray

(1) Valspar Anti-Rust Armor Spray

(1) Rust-Oleum Acetone

(1 gallon) 1-2-3 Zinsser Bulls Eye Water Based Primer and Sealer

(13) Dupli-color Rubberized Undercoat

(2) Liquid Nails Roof Repair caulking

Tools Needed:

Paint brush

Paint roller and tray

Protective goggles

3M Respirator Mask

Power Drill with Wire Brush

Orbital Sander

220 grit Sandpaper

Dremel

Van Build Process

Rust Removal

There were two kinds of rust on our Sprinter van: the small splotches of rust on the interior siding and doors (resulting from scratches, scrapes and dents), and the all-over rust on the steps and under the floor mats (resulting from pooling moisture).

Small splotches of rust

To remove the small splotches of rust on the walls, doors, and floor, we tried using a cordless drill with a wire-brush attachment. This worked great, however the battery kept dying on us, so we moved on to using an orbital sander with 220 grit sandpaper. This was effective for removing rust in large even-surfaced areas. To get into all of the tiny nooks around the side panels, we used a small Dremel with a wire-brush attachment. We then used an automotive Acetone to clean up any remaining rust flakes that had fallen around. (Rust leads to more rust even if it is just a small flake.)

All-over rust

Under the steps, there were some spots that were rusted-through.  In an ideal world, we would have cut those areas out and welded metal back on.  Unfortunately, we don’t have the means to do that; so we just treated it as best we could with a Rust-Oleum Rust Reformer Spray A layer of this flat-black coating bonds with rusty metal and instantly transforms it into a non-rusting surface. There is no need to sand down to bare metal, we were able to simply spray it directly onto the rust. It’s not the most ideal solution because 1. The rust has already led to a loss in structural integrity (i.e., holes) for the affected areas that we won’t be regaining just by spraying, and 2. Any rust that we couldn’t directly spray/reach with the rust reformer might still be left. Those areas are non-crucial, though, so we’ve just ear-marked it as an upgrade/repair to make later if we have to.

Rust Prevention

Inhibitor

While sanding certain areas of the Sprinter van, we ended up getting down to bare metal in order to remove deep rust. In areas that had been pitted, it was hard to make sure we could reach every nook-and-cranny with sandpaper, so we did the best we could and then we sprayed Valspar Anti-Rust Armor Valspar Anti-Rust Armor Spray. This is a rust inhibitor which slow down the oxidation process in metals which have been exposed to oxygen and water. We decided to take this extra step just in case we didn’t get 100% of the rust in hard to reach places. We also sprayed this on all of the seams.

Primer

After completely removing (or reforming) the rust, we applied a layer of 1-2-3 Zinsser Bulls Eye Water Based primer sealer to all surfaces. This is an acrylic formula that is both mold and mildew resistant, and provides a rust inhibitive coating. We also selected this particular primer because it can adhere to glossy services, meaning we didn’t need to sand any more than we already had. Equipped with just a paint brush and paint roller, priming was a fast and simple process.

Undercoat

Following the primer, we applied a rubberized undercoat. This is a protective coating with resistance against moisture and corrosion. It is also paintable, although this doesn’t apply to us. We started with one can of Rustoleum Undercoating – however, we quickly found that this brand was too thin and didn’t spray very well. We switched to the Dupli-Color Rubberized Undercoat and found it to be much better quality for our purposes. It took us about 13 spray cans to completely cover the walls, floor, and ceiling. You can also purchase the professional version which includes a sound eliminator for protection against road noise and vibrations.

The spray undercoat seemed to work well except that a few days later, it was still coming off on our shoes when we walked across it.  Ideally, we would have been ready to put down the framing and sub-floor sooner so that we wouldn’t be walking around on the undercoat layer; but, because of our schedule, we didn’t have that option.  Another option, instead of using undercoating, might have been just to use a basic automotive paint.

Caulk

As a final step, we sealed all seams in the roof with Liquid Nails sealant. This caulking is ideal for waterproofing and stopping leaks, and can be used in high-temperature applications. Again, this isn’t a mandatory step in a van build, but we figured the $5 extra bucks wasn’t too much to pay for an extra layer of protection.

Van Build Lessons Learned

• We would have considered using an automotive paint as opposed to the Rubberized Undercoat spray.
• While we were applying the primer and undercoat, we left our back doors and sliding door open for ventilation. Because of this, we completely forgot to do these areas. Oops!

***Disclaimer: We are not professional woodworkers, electricians, or builders…but Scott is a physicist, so he thinks he is all of those. When converting a van into an RV, there are countless options for materials and methods. We just wanted to share what methods worked best for us.  🙂