A bit late for Tech week, but here it goes. I put a 49 Caddy front bumper on the rear end of my 46 Chevy coupe. The Caddy bumper has outward 'bumps' on each end, which figured out well into my design ideas on restyling the Chevy. I had some extra door 'bubbles' that I used to put extensions onto the quarter panels, to visually lengthen the car a bit. Also to add more teardrop shapes to the car's profile. So, once the quarter extensions were done, I needed to make a filler panel to go between the body's new contours, and the new bumper. Too much work to try to modify the original pan, so I made one using a hammer form. First off, I made an exact pattern out of regular poster board. It is stiff enough to hold a shape, yet flexoble enough to bend into the downward curves at the ends of the bumper. (Sorry to do this in multiple posts, but I don't know how to post multi-pics yet!)
Here's the start of the cardboard pattern. It must be very precise in both how it fits ot the body, and it's outer edge, also.
Once the cardboard pattern is finished, transfer the pattern to MDF. I used 3/4" for extra strength. 1/2" would probably be OK, too. I then cut out a piece of 18 ga. steel, making it about 3/8" larger all around, to make the mounting flange, on the body side, and the outer lip, to keep it's shape. You also need anouther piece of wood, either more MDF< or plywood, the same shape as the pattern, to clamp the steel in between. Here's the 3 pieces, from top to bottom...MDF pattern, steel sheet, and part of the top pattern.
Clamp the steel in between the 2 patterns. Use as many clamps as you can, or have available. C clamps, vise gripe, bench vise, can all be used to keep the pieces together. You can move them around somewhat as you work, just don't disturb the relationship between the pieces.
Next, using a body hammer, hammer the flanges around the entire piece. GO SLOWLY! Use many light hits instead of a few hard ones. Some of the steel is going to be stretched, and some of it is going to be shrunk. It is better to do this slowly, and let the steel slowly take it's shape, instead of forcing it. It may wrinkle, or split, if you force it! Here it is hammered into one of the curved sections. As you can see, the flanges are very smooth, despite the change in shape it has gone through. It is amazing what you can do with steel with the right tools, and some knowledge! The edges will be marked off, and trimmed evenly when it is all done. It may be necessary to use a dolly, piece of pipe, or a chunk of wood, ground into shape, to hammer some parts of the steel into the form, like into tight curves. Use whatever is handy, if you need to.
When all the hammering is done (about 2-3 hours here, with breaks to rest!), remove the clamps. Carefully pry out the steel form, it may be difficult, if you did it right, as it hugs the form closely! Here is the completed splash pan. Almost no additional bodywork is needed. The ends do need to be curved to follow the bumper's shape. I had planned to use a shrinker stretcher to do this, but it proved to be too difficult. I cut out the straight sections, and welded in a curved one for the right shape.
Here it is mounted to the car. As you can see, I did miscalculate the shape a bit. I had to cut it in the center, and re-weld it back together, as only one side would fit tightly, while the other stayed about 1/2" away from the body. Only one cut, and very little adjustment was needed. I'm not that good yet with these techniques to get them perfect! Practice, Practice!
That's it! Finish shot of the bumper remounted to the car for final fitting...the curved edges. Don't have those pics developed, but you get the jist of it! I'm not running regular tail lights in the coupe. I want an early Barris (late 40's-early 50's) look, and I decided to put the tail lights into the bumper guards. The stock 49 Caddy guards have a great shape, like a 50's space gun/water pistol, and I am using one 'bump' of a 52 Buick tail light installed in each bumper guard. I have some pics of doing that, though not in great detail, if anyone's interested! Got a TON of work done on the Chevy between the holidays, with my time off! Narrowed a 50 Caddy bumper up front, and trial fit my 50 Chrysler grill, with custom made end pieces, which just came back from the chrome platers, also.
looks great. what are door "bubbles"? why round the edges? is it a strength issue? can you post a pic of the whole car?
Here's the only shots I could find in a pinch. The door bubbles are the extensions of the fender into the door...you can barely see them in this pic. Here are the bubbles off the car, and being cut up to splice onto the quarter.
Very nice. Great post and looks like it will be a great car. I have formed pieces over wooden bucks, but did not clamp on a top piece. I am sure that is why I had such a hard time keeping the pieces flat. I need to try this. Neal
50mercfan...I'm assuming you mean "why hammer over edges?" Well, for the pan to keep it's shape, and not flop around, it need to have the edges folded over to 90*. The bends keep the panel stiff. The 90* fold on the body side also serves to attach the pan to the body, with sheet metal screws. I made the flange a bit larger on that side, for this purpose. Is this what you're asking?
chopolds if you want to get rid of your grille on the car let me know I got a guy out here looking for one...Thanks Danny
yes thats exactly what i meant, sorry for the confusion. and i see what door bubbles are too. could you weld that panel on? or is that a bad idea? i really like that bumper on the rear looks great.
How did you keep the folded down part on the curves from wadding up on itself? I've seen pieces cut out before, then welded. Did yours come out as a smooth piece? Very interesting post!
Thanks, merc. Yes the panel could be welded on. In fact, it is with a lot of thought on the subject, that I decided to leave it a bolt on. Many 'later' customs DID have molded in pans, and I wasn't very sure it was an 'era' thing for MY car. My research showed both ways (in late 40's-early 50's), left stock, and bolted on, AND molded in. It was a tough decision, but mostly decided on due to the fact that you may NOT be able to install the bumper, with the pan on. It is wider than the insides of the bumper, as you can't see the edges of it, they extend about 1/4 to 1/2" under the edge of the bumper, even at the sides. That, and I didn't want to have a lot of warpage where the pan meets the body...I also had to shorten up the trunk lid, to clear the bumper guards! I did a lot of work to form the panel below the trunk, with hand built channels, and all, and didn't want to warp it by welding on the new filler panels. That's the kind of warpage that is not easily corrected, if correctable at all!
i understand what you mean about the era thing. i'm the same way. i don't like early 60's trends mixed with, say, late 40's trends. that takes away from the appearance to me. but most people don't notice. anyway, great post. i can see hammerforming in my near future. everyweek should be tech week.
Desertratrodder, the steel actually shrinks, as you hammer it into shape. This is due to the fact that you are using a hard hammer, and pushing the steel onto a shape (wood) that can absorb some of the shock of hammering. If you hammered steel against steel, it would stretch, instead of shrink. By using a softer backing it allows the steel to take a shape without distorting. Of course, it is very important that you proceed slowly, with light hits. It DOES begin to 'tuck' into wrinkles, but as you hammer gently, it smooths out. Amazing!
I guess that means more patience... something I Really need to work on.. I'll add that to my resolutions post. I could see myself trying to make something like that and end up chucking it across the garage. More than once. We'll see.. There will be a day..
Nice job!!! I'd like to see the bumper guard lights, if they're handy...I plan to do the same thing on the '38, and I like your skills! Thanks, Steve
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