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My Triumph Obsession, Part VII: Preserving metal with epoxy

Published in blog.hemmings.com

With my 1960 TR3A’s body structure ready to be primed, I applied two double-wet coats of epoxy primer on a warm, dry September day. All the time-consuming preparation was well worth the effort as the primer laid down level and smooth. All photos by the author.

The Coventry saga continues with getting the body on my Triumph T3A prepped and covered with primer. With warm days becoming few and far between this time of year, I had to work fast because the epoxy primer needs an ambient temperature above 65 degrees for proper adhesion. Hours of grinding and dozens of sanding discs later, the TR3A’s top side was ready to be primed.

Using my pneumatic angle die grinder and 3-inch coarse discs, it was a laborious task to remove the surface rust as well as the old epoxy primer that I had sprayed on some 10 years earlier. This was followed by smoothing the entire exterior surface and engine compartment with a 5-inch dual-action sander using 80- and then 120-grit discs. Finally, I went along all the body seams using a stiff 3-inch wire wheel attached to the die grinder, to ensure not a single speck of rust remained. A mask, gloves, and safety glasses were a must, as was a window fan to aid in removing the dust from inside my garage.

Triumph TR3 front inner fender bare metal

Prior to applying the epoxy primer, several days of laborious sanding was needed to get down to a smooth, bare metal surface. Degreasing followed by etching the surface with Metal Prep ensured the primer would adhere properly.

Because the die grinder spits out tiny droplets of oil-mixed spray, the entire surface was comprehensively washed with Dupont Prep-Sol cleaning solvent to remove the grease and dirt. This was followed by a thorough etching of the bare metal using Metal Prep and clean rags. Then once the entire surface was neutralized with warm water and dried, I used a tack rag to remove every trace of dirt and dust that had settled onto the bare metal surface.

Using my HVLP spray gun set at around 25 pounds of pressure, I applied two double wet coats of epoxy primer, waiting 20 minutes in between for the first coat to flash. Thanks to the dry, 72-degree weather that day, the epoxy primer laid down nice and even. Now the primed body will have to sit and wait for the warmer spring weather to return: Then, the painstaking steps of applying a skim coat of body filler, followed by lots of laborious sanding, an application of a high-build primer-surfacer, more sanding, primer-sealer, then the color topcoats, begins. Yes, painting cars is a long, labor-intensive process, but if you don’t rush it and do all the proper steps needed to ensure a smooth surface, the results will amaze you.

Triumph TR3 bare body

With few days of warm weather remaining, I didn’t have enough time to prep the interior of the spare tire compartment so this area will have to wait until spring to be primed.

 

Triump TR3 driveshaft tunnel sealed with epoxy

Before I turned the body over to receive its coats of epoxy primer, after the entire underside was given a coat of POR 15, I scuffed the surface using 320-grit paper then applied two coats of 3M Seam Sealer to every body panel seam, as this will seal them from water and moisture penetration.

 

triumph TR3 metal sealing epoxy

Although this area of the body will be covered by the front fender, for added protection I applied two coats of seam sealer to help ward off any future corrosion.

Triumph TR3 inner fender

Even the seams throughout the front inner fenders were given two coats of seam sealer. Each inner fender will further be protected with a coat of 3M Body Schultz undercoating, then top-coated with several coats of the exterior body color. One can never have enough protection.

 

Triumph Tr3 firewall epoxy

Prior to priming the outer bodyshell, after I applied a thick coat of Rust-Oleum Red Damp Proof Primer to the entire inner body structure, I used a small brush to apply a coat of POR 15 into every body seam. This will be followed by two coats of seam sealer before the application of a primer-sealer and the color topcoats. The chances of this Triumph ever rusting again, at least in my lifetime, are slim at best.

 

Triumph TR3 body in white

With the entire body shell now well protected, I can now relax through the winter knowing that no corrosion will have the ability take hold. As soon as the weather warms up come April, the process of prepping the primed body for its final color coats will begin. I truly can’t wait.