Hood Body Solder Work

I spent most of the afternoon applying lead-free body solder to the damaged areas of the hood.

When I bought the car it had been fitted with hoodpins, which are not original to the roadster. Previously I removed the pins from the body and welded closed the holes in the hood. Today I got started by cleaning up those patch areas using a 3M Clean ‘N Strip wheel in my drill.

It was important to clean the area because the Metal Prep I used to inhibit rust formation leaves a thin protective covering over the bare metal, a coating I wanted to remove before applying body solder.

There were some other areas of the hood that would also need soldering. The hood had clearly suffered from a collision to the front right of the roadster and I had previously welded up a crack along the edge of the hood lip. But the lip itself remained a bit wavy. Here is that area before and after I cleaned it.

There was also a small dent on the passenger side toward the top of the hood.

And a larger dent on the other side of the hood.

After cleaning the metal with the wheel, I wiped all of the areas with acetone to remove any dirt or grease on the surface.

The body solder will not bond directly to steel, so I needed to apply a tinning compound that bonds to the steel and then bonds to the solder. I brushed on the tin generously.

Next I heated the tinning compound using my Propane torch and wiped it using a clean shop towel to remove any impurities that burned off.

Here is a shot after the tin was applied. Afterwards I washed the area using clean water to remove any acid residue that the tin can leave. Skipping this step could lead to rust later.

Then I applied the solder using my propane torch. I had to move fairly quickly, and with the hot solder in one hand and on the verge of running off the hood and the propane torch in my other hand it was difficult to take pictures. I got one about halfway through, and another after I judged I had applied enough. My philosophy with the body solder has become to apply more than enough and grind it back as close to smooth as possible, rather than try to work it with a paddle, which I find is very difficult to do.

I followed the same steps of cleaning, tinning, cleaning, and applying solder to the hood pin areas.

And to the small and large dents in the hood.

Next I finished working the repair on the hood pins. I started to shape the solder roughly level using my angle grinder with three stacked cut-off wheels, which creates a broader flat edge to cut away the metal.

Using the grinder I was able to get the profile of the repair fairly flat.

Then I finished smoothing the repair using some 120-grit sandpaper and a sanding block. The result was not perfect, but close. This area will require only a thin coat of body filler to be undetectable under paint.

Here is the profile.

The larger dent in the hood deflected with heat, probably because the sheet metal was thinned from grinding when originally repaired with body filler. So solder was not very useful in that area, and I will use body filler to address that area later. But the smaller dent took the solder well and the final repair was very smooth.

I finished the day grinding the solder as smooth as I could on the hood lip.

Rear Fender Patch Cut-outs

The first thing I did this afternoon was cut-out some steel patches for the rusted holes in the rear fender wheel-well lips. I roughly measured the size of the three patches I’d need and cut them out of 18-gauge steel using a metal cut-off wheel in my angle grinder. I shaped each as a rectangle, and rounded the corners because welding sharp corners can be a challenge. I find it easier to weld the radius of a rounded corner.

Here is a picture of the rusted hole in the right rear fender lip that I intended to patch, and one showing that my patch was large enough to do the job.

I traced out the perimeter of the patch on the fender using a black marker.

Later I will cut-out the bad sheetmetal and weld in the patches.

Right Rear Fender Dent Repairs

This afternoon I spent about three hours working on some dents and dings in the right rear fender. Behind the right rear wheel was a crease-like dent running up the fender, maybe five inches long. I went over the area with a black marker to isolate the low area–the marker essentially acted as a guide coat.

After the whole area was colored black I used a sanding block to sand it off again.

Then the low spot of the dent was clearly apparent as the dark area where the marker remained.

I used a dolly and a slapper, tools that came in a set I bought from Harborfreight. I placed the dolly inside the trunk up against the low spot in the fender.

Then I used the slapper on the outside of the dent to actually strike the dolly through the low spot in the metal. It is counter intuitive, but the slapping on the outside actually causes the dolly to raise the metal upward upon impact. I used the slapper rather than a body hammer because it has a much broader face, making it easier to strike the dolly. The important thing was to position the dolly in the right spot. Every time I connected, a bit of the black marker would show the impact, allowing me to locate my blows strictly within the low spot of the dent.

After working for about thirty minutes with the dolly the dent was beginning to rise, so I moved to my shrinking disk to try to level out the surface. When the dent occurred the metal stretched both downward at the crease of the dent but also upward at the edges of the crease. The shrinking disk would enable me to lower those raised areas on either side of the dent. I quenched the heated metal with a spray bottle containing water.

I repeated the shrinking and quenching several times.

Here is a look at the dent from above, showing that it had come back into alignment somewhat.

Next I repeated the process with the black marker and sanding, which revealed that the crease had become decidedly less pronounced and that the surface was more uniform.

Then I went back to work with the shrinking disk until I was satisfied that the metal was very close to its original shape.

On the same rear fender, up on the ridge of the body, there was a small dent that was very obvious because of its placement on the body line. I used a Clean & Strip wheel to clean the metal in preparation for applying tinning compound to repair the area with body solder.

I brushed on a thick coat of the tin.

And I heated the tin with my propane torch, wiping away the impurities and spreading the tin uniformly across the surface.

After the tin was applied I began heating and applying the body solder.

I tried a new method this time, different from the way I applied body solder to the passenger-side door. Rather than try to form the repair with the clumsy paddle, I just applied an excess amount of solder so that even the lower edges of the repair were above the original metal, reasoning that I could remove the excess and get a smooth repair.

In my 4 1/2″ angle grinder I mounted three cut-off wheels on top of one another. This gave me a thicker profile so I could use the edge of the wheels to grind away the solder. I went to work grinding the solder repair and the grinder worked very well. The bottom cut-off wheel actually wore away, leaving the three wheel edges at an angle so I could use the edges of the three wheels to smooth the edges of the repair.

After several minutes of careful grinding the area came roughly into shape.

Then I hand-sanded with some 120-grit sandpaper and the area became very smooth and into profile with the body.

And here is a look at the repair from the rear.

There was also a small, quarter-sized round ding in the same rear fender just above the larger dent, located above the side moulding. Below, left is a picture of it after I used the black marker to show its low spot, and to the right is a picture after I cleaned the area with a Clean & Strip wheel.

Using the same methods I used on the other dent, I applied the tinning compound, washed the area, and applied body solder.

And after grinding and sanding the ding was back in good shape.

And I followed the same procedure to solder the larger dent down below. I stripped the metal, then wiped it with acetone to remove grease and/or marker that remained.

Then I applied the tinning compound, followed by the solder.

Here is the solder applied over the crease, proud of the surface, and after I did some grinding and sanding of the area.