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How to fix a bullet hole

We encounter still more unusual damage as we work on our long-term Jeep restoration project

Working through the rebuild phase of Project CJ3A, our on-going Jeep restoration series, we keep finding unexpected problems. After uncovering all kinds of unusual damage, we’ve found ourselves repeatedly asking, “How the heck could that have happened”. Much of it seemed to be the result of abuse and previous sub-standard mechanical repairs. This time as we began prepping the windshield frame for new paint, we had to ask that question yet again when we found what looks like an old bullet hole. We didn’t expect to have to fix a battle scar on a civilian-model Jeep.

By the way, the “CJ” in the Jeep’s CJ3A model number stands for “Civilian Jeep,” which makes it slightly different than the military models Willy’s Overland produced during this era.

Fortunately, taking care of this kind of damage is a pretty straight-forward process. Here’s how we did it.

The first step is to get all the deformed metal around the hole back into position. It looked like the bullet was shot from the front of the Jeep, pushing the metal backward around the edges of the hole. Hopefully, nobody was sitting in the seats when the bullet whizzed through.

Using a body hammer and dolly we lightly tapped the deformed metal edges back into position. Holding the dolly under the low side of the deformation and tapping with the hammer on the high side, we gradually worked everything flat again. (We used a proper automotive body dolly, but any heavy piece of solid metal with a smooth surface would work almost as well).

The concept here is the dolly supports the surrounding metal on the opposite side of the hammer blows, preventing the force from just pushing the deformity out in the opposite direction. Just use very light hammer taps when doing this, gently working the metal back to where it should be.

After that step, we were still left with a jagged-edged hole in the metal. It was impractical to try and fit a patch into that small, irregular shape. So, using a step bit we drilled out the damaged area to create a smooth, almost round hole surrounded by good, straight metal. In this case the damaged area was very close to another overlapping layer of steel. It wasn’t possible to drill out a perfectly round hole without cutting into that top layer and creating even more work for ourselves. Instead, we elongated the hole to remove all the material we needed to.

Once the damaged metal was drilled out, we placed a piece of thin cardboard underneath the hole and traced the shape onto it. That gave us a pattern to overlay on some new metal and cut out a patch. We then put the patch into the hole and held it in place for welding with a piece of masking tape on the underside. You could also use a welding magnet to do the same thing.

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Get out the welder

Using a MIG welder with .023 gauge welding wire, we butt welded the patch into place. That butt-welding method is key to creating a repair that is undetectable from either side of the windshield frame. Remember, welding thin-gauge sheet metal requires a go-slow approach. Burning a series of tacks with short arc bursts around the entire patch is the easiest way to get the job done. Continue making short tack welds until the edges of the patch are entirely welded to the surrounding metal.

An angle grinder with a 40-grit flap disc was used to grind the weld bead smooth with the surrounding surface, leaving the patched area as one solid piece of steel again. But this process often leaves a few small irregularities on the metal surface that would mar a good paint job, so a skim coat of body filler was applied over the repair to fix that. When applying it, we layered it on slightly thicker than we needed for the finished job, because it will shrink slightly as it cures.

Hitting the cured filler with 120-grit sand paper, we sanded it smooth with the surrounding metal, leaving only a wafer-thin layer to even out the low spots. A high-build primer was sprayed over the repair, which further improves the surface finish by filling in any pinholes in the filler. The repair is now completely invisible and the windshield frame is ready for full primer and paint.

But, there is still a lot of work left to do on the rest of the body. †

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