aloy hood

[Gasolinedeniz]

i plan to make a alloy hood for my 65 barracuda (drag style ) now i wonder what is the smartest way to do something ? I plan to make a fiberglas copy of the orig. hood and make a positiv and a negativ out of it . Then i plan to take a 2 milimeter aloy sheet ,put it between my form and screw it together or i lay it under a car and press the aloy sheet into the shape with the wight of my car ? What do you think about ? do this work ?

[Dirty Dug]

You're kidding, right? Check out the plastic garbage bag in your kitchen. That's 2 mm. Why don't you use that.

[Gasolinedeniz]

no dude its serious , its 2 mm not enough ? i mean the ssheetmetal on a car today is about 0.8

[Kevin Lee]

dirty - You're kidding right? Take two dimes out of your pocket and stack them together. THAT is about 2 mm.

running over a fiberglass form with sheet aluminum sandwiched between sounds like a fine way to make a hood. http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif When you think of something like that just say it out loud and see if it still sounds like a good idea. http://www.jalopyjournal.com/ubbthreads/images/graemlins/smile.gif

[C9]

I don't think it will work.
Most aluminum sheet alloys have spring back and the aluminum needs to be pressed further than where it will end up at.
Unless, you're using a large press that generates tons of pressure for the steel dies.

Fwiw - my dad and I built a tube framed soap box car - for a local citrus town race called the Citrus-Crate Derby and dad's were allowed to help (unlike genuine Soapbox Derby cars of the time where the kid did it all) and the rules were pretty open.

Dad got some thin corrugated aluminum and we tried to flatten it out to use as body panels.
Dad finally drove a big oil field truck back and forth over it on a cement floor using the dual rear wheels to flatten it out a bit.
It did go pretty flat, but you could still see the corrugations.

The hood in question is reasonably flat.
Why not make it in two halves and do the compund curves with either an English Wheel if you have access to one or some careful work over a large sand filled bag with one of the rounded plastic forming hammers?

Barring that, make a hood with a simple - single - curve to fit then build a scoop to disguise the lack of compound curves and weld it in place.

If nothing else, make up a small scale fiberglass form, do the car smashing bit and see what you come up with.

[Rocknrod]

If ya dont care about your current hood... and you dont want to add to the cowl... why not slice yours up? Cut out the reinforcements, an tack some thin stuff across for some rigidity?! http://www.jalopyjournal.com/ubbthreads/images/graemlins/confused.gif

[modernbeat]

For comparitive evaluation...

The dimples for the rivets in an airplane skin are about .25 inches in dia, about .125 inches deep and go through two layers of .040 sheet aluminum.

They require 5000 lbs of pressure to adaquately form the dimple.

That's not the pressure it takes to set the rivet, just the pressure it takes to form the dimple that the rivet head sits in.

I'd recommend making a hood from a few pieces of aluminum welded along the contour lines. Use a Henrob or a TIG welder to stick the pieces together, grind and polish as needed.

[SamIyam]

I wouldn't waste my time doing either an alloy hood or a fiberglass one.
Senseless work for the sake of "doing it"... is, well, sensless.

Spend your time and energy one something worth while on the project.
Build an intake manifold or a header.
Build a guage panel.
Build some subframe connectors or a roll cage...

A lighter hood does absolutely nothing measureable for a car like that... it would have to be a sub 8 second car before you'd see any benefits.
Sam.