Rear Bumper Question

mrsbojigger

I have a problem, I think! Is there a difference between curves and lengths of the 2 outer pieces of a bumper for a '51 and a '53 Stepdown. The reason I am asking is that the outer 2 pieces don't seem to match the curvature of the center piece of my bumper. They are close but when attached they just don't look correct. It seems they should transition into each other better. There was a lot of gleaning of parts off my parts car in Oregon and bringing them to Texas. It might be a mixture here. Could the outer pieces be from a '53? Any ideas?
Peace,
Chaz

This is what I have.
Attachment not found.

[Deleted User]

I don't know much about those years Chaz, but the rear bumper on my '50 transitions perfectly from the center piece to the outer ones. Maybe they are from different years.

Jay

SuperDave

They overlap each other The bumper guard covers the lap joint. The outer ends are on top of the center piece. All the bumper outer ends are the same 48 thru 53.

mrsbojigger

Hi Super Dave,
Yes, I know they over lap so the bolt holes will match but maybe it's just me. I want a smooth transition from one to the other. It seems to have an angle at the connecting point and then curves onward into the fender. In other words two distinct curves coming together at a tangent point. They are not damaged in any way so that was ruled out. Maybe I'm just too critical being an Artist but I SEE stuff like that. When our Church was newly built, I would sit back about 50' from the front where there were 4 wall mounted lights mounted between the stained glass windows. 3 were straight and 1 was slightly tilted to the right about 7/16". Every week I had to look at that off kilter light and think why don't they see that.. I finally had to mention it to one of the staff. He said "you know you are right, it is off kilter. I never noticed". Such is the life of an Artist who has been trained to SEE.
Peace,
Chaz

bent metal

I think they are all like that. You don't notice it with the bumper guards on. If you want it smooth with no bumper guards you have to trim the end piece so it's a butt-joint and then shrink down the radii a little bit. Then too your going to have to deal with the end mounting brackets. After the bumper is one piece it won't slide on with the factory mounts and the bumper bolts welded in smooth. Not a huge deal, but you'll have to do something there. But you probably noticed that already.

mrsbojigger

bent metal wrote:

I think they are all like that. You don't notice it with the bumper guards on. If you want it smooth with no bumper guards you have to trim the end piece so it's a butt-joint and then shrink down the radii a little bit. Then too your going to have to deal with the end mounting brackets. After the bumper is one piece it won't slide on with the factory mounts and the bumper bolts welded in smooth. Not a huge deal, but you'll have to do something there. But you probably noticed that already.

Yeah, that's what I was thinking. I can shorten the tips and weld them to the center part of the bumper. I am trying to figure out how to change the radius to create a sharper bend with a better flow. As for the outer bumper brackets, they are already off so new ones will be designed and made.
Any ideas of how to shrink the radius? I know how to shrink thinner sheet metal but this is quite a bit thicker. I would try having it done by our local bumper straightener guy but the chrome shop is very "tight lipped" about letting anyone know who does their work. Here is the illustration I posted in another thread about Lola.
Peace,
Chaz

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rambos_ride

Chaz,

I know you'd rather do this the "right" way shrinking and streching.

But, given the thickness of the metal...On the end caps why not pie cut and re-weld the bumper ends to radius you're looking for?

Addendum: Or you can wireframe the extensions and use your current tools to skin the wireframe with sheet metal - of course your work would need to be flawless (as always) to get the chrome looking correct.


Dan

TOM-WA-

You got me curious so I took a look at the rear bumper on my 54 Wasp..



There is a seam where the pieces join and I guess it would be more noticable if it wasnt for the fact that the verticle bumper guards pretty much

cover and hide the seam



Hope that helps

mrsbojigger

Yes, there is a seam but it is an over lapping seam. The bolts go thru and into the bumper bracket. With no bumper guard it's an ugly site.
I will be keeping the inner bumper guard/license plate light mount though for some protection. I had thought of what Dan suggested and it may be the best way to go since this is a standard practice. I would have to figure out how many pie cuts I would need and do some flawless welding. Another way would be to pie cut the outer edge horizontally down the high point and roll the edge over to the desired curve and weld, then add small pie shaped pieces to the back edge.
Could do it my wife's favorite way of solving a problem. Duct Tape! Naah!
Peace,
Chaz

Dan,
Speaking of wire frame, that's how I will be forming the streamlined area of the trunk and rear fenders to get that flowing look before forming the sheet metal.

bent metal

I would shrink it. I would use the center section as my "control" or guide, whatever you want to call it. Then set it all together on the car and take a look. I think you'll find the outer end pieces don't fit the top edge where it meets the body as good as you'd like. They usually don't there. I'd fix that first. Once that's done I'd trim back the outer pieces only. Leaving the center piece alone. Once you have a good butt joint, don't bevel it yet, check your radius/contours to see where your at. I think it's going to look like they meet at a peak. But it will be less than before the butt joint was made. From there I would start shrinking everywhere that you imagine you would "pie-cut". Starting with the biggest offender and extending in about an inch deeper than you think it needs to change. That area is going to be the leading edge, the first surface that would touch if you were to back into something while driving. Then go from there.



Ideally, I would want the chrome guy to remove the chrome before I even started.:)