Restoration of My 1948 Prefect
Rear Apron, Boot and Lid
The apron below the boot had been pushed in and pretty beat up before I got the car. I originally filled it with bondo but now it is time for a proper repair. The apron also has some structural integrity as it is the mounting point for the lid hinges. The same incident also cracked the body on both sides in the bottom corners of the boot opening. The boot lid has some minor oil canning in the middle. This repair requires welding and removal of the fuel pump, filter and tank. I knew there was some pretty deep filler in the apron but I did not expect the repair to be a major undertaking. Therefore, I originally intended it to just be part of a chapter. I was wrong. Here it is as a full chapter in itself.
After removing several layers of bondo and some other filler material, I was able to better diagnose the cause of the damage. There was a fairly clean but deep wrinkle just below the center of the panel and 80 percent of its length. It was not the result of a collision. It was, instead, the result of some DPO (dreaded prior owner) thinking the boot floor might be a good jacking point. This not only bent the floor and cracked a couple of spot welds but it also buckled the apron which was attached to the floor along its bottom edge. The dent would not pull out and there was not enough work room behind it to work it out with hammer and dolly. I eventually had to remove the entire panel, cut the bottom half off and make a replacement piece.
Removal and making the replacement piece was fairly straight forward but welding it back together was more problematic due to distortion from the heat. Replacing the entire panel would eliminate that problem but the top half has pockets and reinforcement for the boot lid hinges. That would be a major, or nearly impossible, job to reproduce without the original factory dies and presses. These photos give an idea of what I had to deal with. The first one shows the apron after a little of the bondo fell off or was removed. The other two show the damage after all filler and paint was removed. That crease was about 3/4 inch deep. The last photo is the back side of the apron after removal. It shows the reinforcement for the boot lid hinges as well as the serious degradation of the bottom welding flange. This was the point at which I decided to replace the lower portion.
My plan was to tack weld the replacement lower piece to the original upper then finish by brazing the final seam. The problem appeared almost immediately; the compound was racked by the heat to about 20 degrees from end-to-end. I took it apart and tried again, this time with even more clamping and bracing in attempt to control the twisting. This second attempt again failed with the same result. My revised plan was to weld the upper section back in for stability, then weld the bottom to it on the car. I may even resort to brazing if heat still causes excessive problems.
I did repair the rust and distortions in the boot floor with the apron out. Here you can see the shelf with the apron removed. It is for a jack and tire tools, etc. It also shows the structural members at either side that brace the apron and hinge supports to the floor, shelf and body sides. More of these later. I started by removing as much surface rust as I could. I then began welding cracks and small rust-through holes. Patching holes in good metal is slow but not too bad. In rust-through holes, however, it is an entirely different matter; they really want to get larger instead of smaller. Finally, from about center to a little behind the right support, there was just no way to do it other than cut out a large section and replace it with new metal. The problem, of course, was finding good enough old metal to weld the new stuff to. Eventually, the solution was to braze the new metal to the old. I then applied some all-metal filler over the worst of the shelf to finish it off. Hind sight is, of course, 20/20. I believe now it would have been easier to just replace the whole shelf.
That is also the point at which I stopped working on the car for over a year to do the big home remodel job.
For a couple of months after getting free from the remodel project, I experimented with ways to stick weld the upper part of the apron back onto the car. I have an Eastwood Stitch Welder device that is supposed to reduce the output from a stick welder by about 1/2, making it easier to weld thin sheet metal. I burned up a lot of scraps playing with it, thinking I was getting my welder down to about 20-25 amps. After a time, It was welding all right most of the time although it was much messier than normal. About then, I noticed that my welder will go down to 20 amps in DC mode. With that I could eliminate the Stitch Welder. I played with that several more times with a little better success and it also produced much cleaner welds. I did get to feeling fairly good about the welds but I never got to the point that I felt confident enough to actually put it to the test on the car. About that time, my shop landlord ran out of projects and wanted to start restoring my Sprite. Answering his questions and occasionally helping, took a lot of time from the Prefect. Also, about that time, my friend, Harold, seeing that I was probably over my head in trying to weld the apron back on, volunteered to bring his MIG welder down and weld it for me. Since he had just finished an MGB from what was basically scrap, I knew he could do it so I finally swallowed my pride and accepted his generous offer.
Harold came and we temporarily installed the top half of the apron and held it in place with the boot lid hinges. He checked it out and informed me that I still had more preparation work before he could reinstall the apron. Some of the structure did not fit right. The sides of the boot, where I had spent some hours removing dents and dimples, did not align with the lid yet. Finally the gap between the lid and apron was too tight. Over the next few days, I corrected these faults. The boot/lid alignment involved a steel bar, a large C-clamp and more that a few words. The tight gap was a result of trying to weld the upper and lower half on the bench so I corrected that with more heat and some pulling, properly directed.
So Harold brought his MIG welder and his expertise and began welding the original top half back in while carefully maintaining proper alignment. The gaps where I had cut it out were wide enough that he had to first weld backing strips behind. The corners had torn long before I removed it and that also forms a channel for weatherstrip all around the boot opening. Those tears also extended a few inches on either side into the body. Repairing the tears was quite fiddly due to the shapes involved. After it was in and we were satisfied, he then welded in the lower half. By welding, I mean a series of tiny dots carefully spaced so as to control the heat in the surround metal. All together there were several dozen such dots over several passes. The dots form each pass were ground down before the next pass. This actually took a couple of days to complete. these photos show the fit before welding and the actually welded left side. That gives an idea of the number of weld dots and the gap that had to be filled.
Finally, the bottom of that jack shelf is pretty rotten. I should have replaced most of the shelf but even with the apron removed, access was difficult. I opted to fill rust holes where possible and patch what was not. The bottom of the apron was originally spot welded to the turned under edge of the shelf. My solution was to fill the joint with seam sealer then pop rivet the flanges together. Harold wanted to at least try welding first. Somehow he managed to get that done with no major burn holes or other flaws. Here is a selfie with us examining or maybe admiring his work. If you refer back to the shelf photo you will see that the weld seam is actually about 1/2 inch below the shelf floor.
At this point, I had to temporarily step away from the Prefect to help Dan working on restoring parts for the Sprite. I still need to finish grinding away the welds, reinstall the lid and finish working the metal around the edges. Soon, I hope. We got a lot done on the Sprite but then that also got interrupted for another project. Dan's brother, Dick, has a 1929 Model A Ford that was fully restored several years ago but was in a garage fire in 2008. We all decided to begin restoring it which took a fair amount of time from my projects. The process is described here.
Well, as the rush to get the Model A in primer and protected from rust eased a little, I was able to devote a little time to the Prefect. I finished grinding the welds on the apron and flattened it as much as practical. Remember, there is very limited access from the back side and that long weld seam is a lap joint. A fair amount of filler would still be required, probably more than 1/8 inch but less than 1/4. That's almost nothing compared to what was there before. That considered, I decided to use an all metal filler for the bulk of the build up. This is a polyester filler but uses ground up aluminum instead of the softer stuff in typical "bondo". It is not very pleasant to use. No matter how much I stirred, it was still rather lumpy. Although lumpy, it did fully set up. It is also stiffer than the usual stuff and hard to stir. I was never able to get it to lay smooth and sanding is much harder than the non-metal variety as might be expected. The photo with the silver look is the metal filler. You can see the "lumpyness" of it before any sanding. The other photo is the first coat of bondo over it in order to get acceptable smoothness. This was an old can of filler that seemed to be all right but it was dark blue in color, almost the exact color of my cream hardener. That made it troublesome to mix. I bought a new can and will switch over to it instead. Meanwhile, tomorrow we get back on the Model A.
Some "down time" on the Model A due to weather less than desirable for painting, I have been able to spend a little more time on the Prefect. I got the apron finished as much as I want until the boot lid is finished to ensure they match acceptably. So I started on the lid. There were some visible cracks, suggesting excessive bondo so I stripped it down and found even more than I expected. It had to be straightened a lot. This was made more difficult by the double panel construction. The skin was thoroughly crimped to the structural panel and I was afraid to risk removing it since replacements are not available. My solution was to remove the inner panel, one quarter at a time, preserving the structural integrity, to work the dents out of the skin. The first photo here shows it with the filler removed and some work started in the lower left section.
Notice the upper right quarter is relatively smooth and straight. The lower half was bent inward about half an inch and was quite rough as can be seen by the paint bits that the D/A sander was unable to reach. The next photo shows the lower left quarter of the inner panel removed for access to the back. I will work that section of the skin until acceptable then weld the structure back in and proceed to the next section until the whole thing is ready for finishing. The right photo shows interim progress in the lower left after some straightening and shrinking three stretched patches. The areas near the lower left corner where the smaller dark wrinkles are where the shrinking was done. It seems the tar painted on the back side interferes with hammer and dolly work and will have to be removed next. Notice though the difference in the worked panel between these two photos.