Fabricating an Elva passenger seat–by replicating the driver seat

Update by Tim Suddard to the Elva Mk VI project car
Oct 17, 2024 | Elva, Restoration, Fiberglass, Project car, Elva Mk VI

Photography by Tim Suddard

Why did we build a passenger seat for our Elva sports racer?

Because that’s what the racing rules of the day required.

A related quote, in fact, from the SCCA’s 1962 General Competition Rules for Modified-class cars like our 1962 Elva Mk VI: “Specifically, two seats shall be offered, but need not necessarily be located on either side of the longitudinal axis of the car.”

While our Elva originally ran at Sebring–not an SCCA event–the SCCA rules show how passenger seats were common and required in sports racers of the day.

Fortunately, our Elva came with a second seat. Period photos of our car, however, showed that the passenger seat resembled the driver seat–which our second seat did not.

While we didn’t have a second seat that looked like the original driver seat, we had plenty of steel, fiberglass resin, hardener and mat. Our plan: We would just build an exact reproduction of the driver seat.

But if we use our driver seat for a mold, won’t the new one be too small? Absolutely–and that would be okay. After all, we had already widened our driver’s seat while moving it a bit towards the car’s centerline to better line up with the pedals and steering wheel. We would just have to remember the slight size difference when we cut upholstery materials.

Fiberglass is pretty easy to use, and materials are readily available at body shop supply stores and boat repair centers. We use a place called Higgs Auto Body & Paint Supplies in nearby Holly Hill, Florida, and everything for this project should only cost about $100 to $200.

A gallon of resin is more than enough for this project. In fact, we have used less than 10 gallons of resin on this whole, horrific restoration.

You’ll also need mold wax, hardener and mat in both light (.75 ounce) and heavy (1.5 ounce) thicknesses. You will also need acetone (the best solvent) to clean the fiberglass resin from your tools and work surfaces.

We use cheap 2-inch glue brushes (available at any hardware or paint supply store) and throw them away after each application. They are hard to clean and not worth the trouble.

You will also need disposable rubber gloves. Large sheets of cardboard make a great work surface as they can also be thrown away afterward.

Wear your personal safety gear, meaning a mask and eye protection. Cover up your arms and legs, too, as fiberglass can be rather itchy. (We’re not wearing masks here as we were shooting a video at the same time.) Work in a well-vented area so you too don’t start seeing Elvas in your sleep.

To properly manage fiberglass resin, you have to work in small batches. Generally, we mix up 4 to 6 ounces. Then add a drop of hardener and thoroughly mix with a stirring stick–or even one of your brushes.

Fiberglass hardens–kicks, as it’s called–at very different time intervals. The weather can play a big factor. On a 50-degree day, for example, it could take all day. Here in Florida, we usually have 20 or 30 minutes of working time while everything will be rock hard an hour later.

Building something in fiberglass from scratch requires a mold. In this case, we’d use our driver’s seat.

When working with fiberglass, usually you can just wax your mold and pull out the new fiberglass piece once it hardens.

But no matter how many times we waxed our seat’s surface, we couldn’t easily pull off our test strips. Worrying about ruining both seats, we decided to place metallic tape over the entire seat and then wax the tape. While unconventional, this provided the perfect solution.

We first needed to build the front seat mount. This is simply a hollow steel rod of decent thickness with a couple of nuts welded on each end. We would also need an upper mounting bracket that we would fiberglass into the inside of the seat for added strength.

These two steps would come later, however. Our initial goal was to just lay up one layer of 1.5-ounce mat over the whole seat and then pry it off the mold. After this step, we could then add layers of fiberglass mat for added strength.

We could then add our top and bottom seat mounting brackets and trim our edges. To add strength, we’ll form fiberglass tubes–stronger than a C-channel shape–along the sides.

We will then sew up new seat covers that match the original driver’s seat: light blue fabric with dark blue piping.

And yet another step is completed with this rather complicated project car.

How do you wire a car when no harness exists?

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