Made the trunk floor today using the same method as the floor. I left a couple of inches on all sides to get a little less war page in the panel. The trimmed floor is trial fit. The flange on the first panel helps. I formed a flange at the end of the panel to keep it flat. The wood piece clamped tithe rear crossmember Keeps the panel at the correct final height.
Now on to the two filler pieces. I chose a size that allows me to finish the tapered section. I made a cardboard template first and transferred it to metal. Getting all the angles right and gaps aligned with multiple bends takes a little effort. Second side tacked in. Everything welded solid and finished. I hope to finish the corner pieces tomorrow.
Got a late start today and I underestimated the time it took to make a template of the two rear extension on the trunk panel on either side of the recess for the tool box. I fit the template in the body shell and made minor adjustments until the fit was satisfactory and matched the rusted out original as far as I could tell. Here is a detail of the body mount. The cupped washer is spot welded to the trunk panel. I measured that I needed 1 1/4" of depth in the panel to get it to the right height.
The plan is to use the wooden buck and an aluminum puck and shape the cup shape using the hydraulic shop press. I sprayed the bottom of the panel and the buck with spray adhesive to increase the friction, the clamp the top wood pieces down to keep the panel flat during the process. First try with the aluminum puck cut the panel around the puck. I only had a small chamfer on it and didn't expect it to cut the panel. I cleaned up one of the original cupped washers and used it to more evenly spread the force. I used grease between the washer and panel.
This seemed to work better, but the panel really stiffened up before I got to the desired depth. Maybe it needs just some extra pressure... there, now it starts moving again... Oops...Mercedes hubcap anyone? The bitter taste of failure... Let's try again and stop when the panel starts to stiffen, then mark the depth on the press and repeat with the second panel. Success! About 1/4" short of the stock height, but will fabricate a washer to take up the space. Now I have two pieces to shape the missing corner pieces. Not the most productive afternoon...
Hey, even Thomas Edison had several successful failures when inventing the light bulb. Thanks for showing the mess-ups / lessons learned as you determined the correct process. Great work!
I disagree. You learned something, achieved something ...and shared it with us. I think that's very productive!
More great work. Thanks a lot for including the mess it took to get there. You mentioned using spray adhesive to increase the friction of the sheet and bottom form. Did you try one without the adhesive? I'm wondering if the slightly lower resistance may allow the puck to full from farther out and get you that last 1/4". Just curious, as I have only limited experience with forming. Looking forward to seeing the finished floor.
I tried that and it resulted in the failed sample with the fold in the material (middle sample in the picture). The problem is that the the force causes less material stretching around the outer periphery than in the middle at the edge of the puck, because the same force is spread over a longer distance. The material wants to fold rather than stretch at the outer edge.
swissmike, If you turn a 90 degree flange all the way around the part to be pressed it will have less distortion.
Agreed, but I feel that I reached the maximum possible deformation with this set up, regardless of the edge treatment. The two finished panel each only had a small wave which could be hammered out with a couple of blows. I used the 90 degree flange idea on the back edge of the trunk floor, but only after hammering the beads.
I transferred the shape of the panel to piece of wood that I can use to shape the metal. After marking the outline I used an adjustable wrench to gradually bend the edge, followed by planishing with the dolly against the wood. Cutting another template to help transfer the outline of the new panel. Tacking in the new panel and test fitting the whole trunk floor.
Fitting the second side in place ensures a correct fit. No rush here, this needs to be accurate else the panel will never fit correctly. Looking good so far... Welding and finishing after removal from the body.
The original cupped washers were cleaned up and primered before spot welded to the panel. I will make a 1/4" spacer to account for the less than stock depth of the recess. Finished, shaped panel. Still needs the openings for fuel sender, filler neck and spring shackles. Here is a question for anybody familiar with these cars: the original rockers have 3 captured nuts along the lower edge. One is visible near the joint on the new rocker. Anybody know what is screwed to the lower edge of the rockers?
Back to work on the floor. The old floor is cut off leaving just a half inch flange. Mating the two pieces made earlier. Measuring, marking and cutting for a lap joint. Here is a little trick i used to transfer hole location to the panel. The space did not allow for drilling from the underside. Even with a 90 degree attachment. The center punch is held in a piece of 2x4". Now just hit on top with a hammer and a piece of wood. The small dimple clearly marks the exact location.
Here is one seat mount location. A 16 ga rectangle is spot welded to the underside. I decided to cut and reeled the perimeter to get the flat parallel to the ground like on the original. However, I woudnt do this again as the seat mounts are only about 2" wide sideways and don't really care about the tiny amount of wedge. Perimeter cut. A larger steel plate is placed under the entire area and the edges hammered down flat, then welded up. Dug out the seat for a trial fit. The welding on the panel of the seat mounts introduced a lot of warpage into the panel, which I couldn't completed get rid of by shrinking along the edge (see far side of floor does not fit edge of rocker. I will have to pie cut and weld a straight reinforcement piece to the underside.
After welding all the small holes used for locating the lower die, I mounted the floor and located and drilled the remaining holes. Some holes are recessed and I made a forming die from aluminum scrap which worked surprisingly well. Test fit of the rockers... Still need to trim the outside edge slightly. I want about 1/8" to 1/4" clearance on the inside of the rockers. The rockers will be welded into the body shell first, then the floor is installed and spot welded to the rockers after the trunk floor and seat riser are welded in place as well. But that's still a long time off. Nobody makes a body mount kit for Mercs, but most of the shims can be cut from flat rubber mat. One of the rear spring shackles is missing, putting the entire chassis into a slight twist. Got to fix that before fabricating the shims. I hope 40 Ford uses the same round rubber bumpers for the floor mounting bolts to eliminate any direct metal to metal contact.
You could try pre-stretching the metal to be formed if you have to attempt this again. That should also help the surrounding metal remain flat. Just my $.02. Love the work you're doing and appreciate the effort you go to sharing/documenting your build.