Triumph Spitfire Battery Box Removal

After too much time, I finally got around to working on the car yesterday. I wanted something lightweight but also something that I had never done before, so I decided to pull out the battery box. Like most, if not all, unrestored Triumphs and probably other LBSCs, my battery box was corroded through on the bottom. The PO had put down a thick fiberglass matt to fix it up. I'll have none of that, of course.

The corrosion. Post removal, obviously.

View from the top. You can see the little red-ish circles where the spot welds are.

A while ago, in preparation for this and I'm sure many other spot weld removals, I purchased a Blair 11096 Spotweld Cutter Kit from Amazon. It got good reviews and came with all of the necessary pieces to remove spot welds as well as two replacement cutting heads and one replacement pilot bit. The pilot bit itself is much like a regular drill bit and is sprung such that with minimal pressure, it recesses back into the tool as the cutter comes into contact with the metal.

What's in the kit

The cutter and pilot bit.

This forms a concave/convex cut in the metal that essentially cuts around the spot weld. The object is to then go back grind down any remaining metal.

Post cut. You can see the two layers of metal here. The center and right is the box and the left is the body.

The first order of business was to identify all of the existing spot welds. I used a wire wheel mounted on my cordless drill to remove the paint and rust to identify the small dimple of the spot weld. The instructions called for using a small drill bit to give something for the pilot bit to rest in so that the tool doesn't get out of control. This is very important as a few of the holes were not deep enough and the thing walked right off the spot weld.

After pre-drilling everything, I started with the spot weld remover. I spun the pilot bit in the hole for several seconds to allow it to make a nice depression so that it would be stable and then applied moderate pressure, bringing the cutter into contact with the metal. I rocked the drill slightly in a circular fashion and slowly cut through. In some instances, it was easy to tell when I had gone through the layer of the top metal as you could feel the drill take a step downward. Other times, it was not obvious and I stopped often to make sure that I didn’t do damage to the underlying metal. Unfortunately, I punched through a few times.

The dash support brackets need to come out as well since they formed the top of the metal sandwich that was the support, battery box and body. The outer strut was relatively easy to remove, though the chuck of my drill rubbed against it at times. However, I was able to drill perpendicular to every spot weld.

The four upper spot welds of the outer support all done.

The inner support, however, was not as easy as the firewall bows out where the suction vent for the heater is and there was much less room for the drill. I was able to get at the three upper spot welds and then had to pull in on the strut a bit, bending it, to be able to reach the remaining spot welds with the ones closest the firewall being cut at an angle. It all worked, though.

Inner support. Bent it up a bit trying to pop some of the welds.

After that, it was quick and easy work to finish out the remaining spot welds. I completed drilling through the battery box for the spot welds that joined it to the body and re-drilled the common spot welds that held the supports to the box.

Most of the way through. The factory was not always neat with their spot welds. No robots, though.

The battery box came right up. I discovered an area of pretty significant corrosion that was under the inner support that will need to be cut out and replaced. Otherwise, this was a simple job, with the right tools, that only took about an hour. Getting the new one in will require much more work, I'm sure. And me learning how to weld.

Area of corrosion on body. So surprised to find rust on my Spitfire...NOT!

The new box will require some bending as it is stamped with the edges flat while installed the back edge flares up a bit to follow the firewall.

New and old. Not hard to tell which is which.

Close up of where the flare of the back edge needs to happen.

On a side note, some of the reviews you will read for the cutter, if you get that far, mentions lubricant also made by Blair. Of course, I purchased the lubricant back in August when I got the kit. And, of course, I forgot that I purchased it and therefore, didn't use it. I also didn't store the cutter and lubricant in close proximity, to help remind me to use it. Even said to myself "you know, some lubricant would probably be a good idea". Dork.