Learning Curve

Tips from a first-timer’s experience prepping and painting

By Jim Youngs

Photos by Jim Youngs, Carolyn Youngs and Monica Benger

Ask just about any specialty car builder how much of the work he did himself and you’re likely to hear, “Well, I did everything but the paint.” Even fearless, burly guys who can make precision components out of chunks of steel on milling machines will cower at the thought of handling a spray gun.

After dealing with hassles from a faulty fuel system, the old tank had to be replaced with a new one, fitted with an EFI in-tank pump.

The first photo here is a very inexpensive Central Pneumatic professional, HVLP spray gun purchased from Harbor Freight on sale for less than $30. Subsequently, I upgraded equipment to include a pair of DeVilbiss StartingLine
HVLP guns: One for primers with a 1.8 mm tip, and one for base coats and clears with a 1.4 mm tip.

But truth be told, today’s paints and painting materials are rather easy to work with and are very forgiving, even for newbies. So consider this piece as an encouragement to pick up some wet-or-dry sandpaper, body filler and a high volume, low pressure (HVLP) gun. We’ll walk you through a fairly typical painting project done by a rank amateur, that’s me, who’d never picked up a pro spray gun in all the years he’s been building cars.

I started our gas tank paint project by masking off or plugging all the openings to keep debris and dust out of the tank. Plastic pipe plugs work well for protecting threaded inlets.

I used the Acryli-Clean to remove all the grease and grime from the raw tank, applied with disposable Kimberly-Clark WypAll cloths. Acryli-Clean has to be wiped on in one direction and wiped off with a clean cloth when dry for best results.

Once the tank was clean, I used a dual-action sander with 80-grit paper to rough up the surface and give the self-etching primer something to cling to. In the areas where the sander was unable to reach, I used Eagle abrasive pads.

For small pieces, PPG recommends applying just one coat of the self-etching primer, so I added a measured amount of catalyst at a 1-1 ratio. Pot life for this mix is 24 hours at 70 degrees F, so no real rush. It can be top-coated in about 20 minutes, and this material won’t require any sanding.

The ideal paint method is to keep the gun set at 5-10 psi, moving parallel with the piece. The primer went on impressively easy, creating a smooth finish. One thing I wish I had done was suspend the tank in the air, in order to spray all the surfaces without having to move it.

What prompted me to learn how to paint actually stemmed from a fueling issue on my ’32 highboy roadster. I decided to buy a new EFI fuel system setup from Tanks Inc. and also a new unpainted fuel tank. Paint is particularly important on a ’32 Ford fuel tank, as a big portion of it hangs out behind the car in full view.

Once the new tank was ordered, the painting project began in earnest with a visit to Harbor Freight to buy a cheap Central Pneumatic HVLP professional spray gun. These are usually under $30 on sale, and I reasoned there was no sense investing heavily since it wouldn’t get much use after this project anyway. I ended up buying a pair of guns, one for primers and one for base coats and clears.

I mixed small batches of the body filler and catalyst and used a small spreader to apply the filler to the low areas.

With 80-grit paper and the sanding block, you have to smooth out the filler to a point where the surfaces are as flat as they can be, which might require repeating this filler/sanding procedure several times. Then wipe the whole thing down with soapy water, and then clean the surface with Acryli-Clean in preparation for the urethane primer surfacer.

When the part has been smoothed
to your liking, it’s time to spray on the urethane primer surfacers, designed to provide a sandable, thick coating that will fill small flaws. After I mixed the K36 primer and K201 catalyst at a 5-1 ratio, PPG recommends adding some DT87 reducer to minimize film buildup and sanding times.

This next step is a critical one and will ultimately determine the final outcome. A primer base should be smooth enough for a clear coat, so I wet-sanded the part starting with 400 grit or finer.

My next stop was Painter’s Supply, a local shop for professional paint and body guys. I needed paint to match the roadster’s silver color, which they were able to accomplish by scanning a sample from the car. I also needed a ream of ancillary items for prep and cleanup. Keep in mind that painting steel and fiberglass requires a few different products, but the basic procedure and materials are the same.

One caution you hear over and over again is to stick with a single brand of primers and paints because they’ve been formulated with compatible chemistries. I went with PPG products including Acryli-Clean for removing contaminants, DPX171 self-etching wash primer and catalyst, DT87 reducer, K36 acrylic urethane primer surfacer and catalyst, and Evercoat metal glaze polyester finishing and blending putty. I even bought PPG measuring cups and a bunch of wet-or-dry sandpaper from 80 to 2000 grit, as well as a foam sanding block. And that was just the first trip to Painter’s Supply, with subsequent trips made for a respirator, primers, tack rags, paint filters, stir sticks and body filler.

After you’ve assured yourself that the component is as smooth as humanly possible and you’ve cleaned it once again, it’s time to apply the color base coat. Painter’s Supply used its spectrometer to scan a painted piece of the car to determine a proper color mix, which in my case was Deltron 2000 DBC with reducer at a 1-1 ratio.

The silver base coat goes on with a matte finish. As done when spraying the primer, PPG recommends two to three coats with five to 10 minutes between coats.

Once the base coats are applied, you only have about 15 minutes to apply the first coat of clear. Don’t let the base coat dry too long. The Deltron Concept DCU2021 clear is mixed with reducer, and I chose DCX61 hardener, which afforded me a 50-minute drying time. PPG recommends two coats, which dry with an orange peel texture that will need to be color-sanded and polished.

For the color-sanding process, I taped off the edges of the gas tank to serve mostly as a reminder to not sand the thinner edges of the component. Starting with 1000-grit sandpaper, I moved on up to 1500-grit and finally 2000-grit, all done wet.

Truth be told, I probably spent more on painting supplies than I would have if I hired a professional painter to do the whole job in the first place. Even so, the skills and equipment I acquired during this first painting project have served me well since. Subsequently, I’ve purchased better gear and taken on bigger paint projects, including a complete dead-rat-flat-black spray job on my current ’54 F-100 pickup project.

I used another Meguiar’s foam pad, this one a finishing pad, to apply the 3M Perfect-It glaze for the high-gloss finish on the tank. Both 3M products worked well and were easy to use.

Painter’s Supply recommended using Meguiar’s Soft Buff foam pad and 3M Perfect-It II rubbing compound as one of the two final steps in the paint process. The rubbing compound smooths out any swirl and sanding marks.

Overall, the paint experience was much less intimidating than expected. About the biggest mistake I made can be attributed to poor lighting in the shop, as I failed to notice a couple of places where the base coat had been sanded through. Both spots, however, were in unobtrusive areas, so no big deal. Since this project, I’ve done numerous other painting projects leading up to painting a whole vehicle.

With the shiny, new gas tank in place hanging off the back of the ’32 chassis, about the only things left to do are remove the masking tape, add the plumbing and bolt it down. Then it’s time for some fun on the road and acknowledgement of a job well done.

As you’ll see by the almost step-by-step account, it’s a lot of hard work just to get the part ready to be painted. Once that’s accomplished, the actual painting process is fairly easy. I’ll admit to a few rookie mistakes along the way, but I’m very pleased with the outcome. And once done, I could proudly say, “I did it myself!” Now all I have to do is learn how to sew upholstery.