Best way to do custom bumpers

[verticalflight]

We have a Porsche that we are working on. '74 with custom, smoother bumpers, tucked in.

Our choices are either:

-- carbon mold the bumpers (we have never done this before)
-- metal work them in aluminum to customize them

Any major preferences between the two choices?

We are worried that getting the carbon just right is going to be real pain.

And we don't know anyone that can build the plugs and lay the cloth.

Best,
Kris

[jlcustomz]

I've worked with steel , plastic, aluminum, & fiberglass on bumpers.
This could be as much about capabilities as to which choice. To make a mold to build a mold of the exterior side of a bumper requires a perfect something to make that mold off of, then actually making them, then making mounts. True cf stuff, not just fiberglass overlays, really should be vacuum formed. Custom fiberglass is more common to do, such as the front of my hood.

Personally I might be going the metal route. Not a Porsche person, what are the original bumpers made from?

Aluminum , such as .090 3003 h-14 can be annealed (heated with a torch) to soften & make more workable, then tigged together as needed or even gas welded. You can get by without all the fancy tools if you can get up the skills . Look at my aluminum bedcover & my intake plenums in my photobucket links.

Steel is much harder to bend in bumper thicknesses, but can be slit more to bend & even mig welded if you don't mind more grinding.

Just a few thoughts. Be glad to give more if you decide on a method.

[verticalflight]

Thanks great input, I am leaning towards aluminum at this point. the original bumpers are very heavy and made of steel. We want to do some drastic reshaping in the rear.

[jlcustomz]

Kinda figured you might want to go the aluminum route.

A lot of aluminum projects I've done incorporated a lot of old fashioned hammerforming. I've made many different wood jigs & mostly beat the metal against it to shape. A yellow plastic teardrop shaped hammer is one of my most used tools on aluminum. Learning to anneal the aluminum with a torch goes a long way towards making the metal do what you need. As you work it , it hardens back up. Difficult areas where the metal needs to shrink a lot such as the upper portions of a more heavily curved area can be re-annealed a few times in the process, cutting down on having to make pie cuts & welding.

If you have any old school skill of torch welding, don't overlook it. You do have to use flux, but the penetration is better & the welded area is more workable as the gas weld is softer & less likely to crack. Could even tack with the tig & then gas weld. Also don't overlook adhesive, such as 3-m 8115, if you want to glue on a bracket to the inside or something without having to worry about warping.