Landracing Forum
Tech Information => Technical Discussion => Topic started by: Paul Powell on August 27, 2018, 11:25:03 AM
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Okay,
What gauge aluminum are most of you using for your body panels?
Looking to move away from fiberglass next year and move to aluminum on our Modified Sports front end.
Will have curves and corners (nothing real tight).
Also what kind of support structure on your panels?
pictures would be great!!!
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Paul;
Moving from fiberglass to aluminum bodywork is a big step. All my car's body is fiberglass but I use flat 7075-T6 aluminum panels as stressed members that are riveted to its steel tube chassis, not as the body itself. My guess at the alloy for forming a body would be 3003 but the thickness would depend on what the shape would be; the more compound curvature, the greater the stiffness of a particular thickness would be. Don't forget that the final skin thickness will depend on how much the panel is stretched.
If the shape of your new aluminum body is generating much downforce, this needs to be addressed in the stiffness of the body panels and in their support brackets.
My fiberglass front body is supported at the nose by a mild steel frame with thin 6Al4V titanium stressed panels (see photo)
Regards, Neil Tucson, AZ
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we use .062
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Paul, You need to use 3003H Aluminum Sheet in either .050 or .063 thickness. This alloy will not crack with forming and can be re-annealed easily with a oxy/acetylene torch.
Aluminum "work hardens" as you stretch it so as you work it and needs to periodically be re-annealed by fogging the sheet with pure acetylene leaving it sooty black.
Next turn on the oxygen to obtain a neutral flame and burn the carbon off and you are ready to attack again.
For what You are doing, with several pieces to fit together and welding required (along with lots of filing and sanding) I would use the thicker .063 and if you are making flat panels that may or may not have simple radius bends I would use .050.
Ron Covell sells some excellent DVD's and He and others have books on metal shaping available on line.
Good Luck and say Hello to Villa for me............
"One Run" Bob Drury
(the proud recipient of the first two years of the Courtney Hizer award for fastest Studebaker at Bonneville... and two of Courtney's cigars!)
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.062 as ORB says, but if it is a panel that has a lot of stretch, I would go .080. I had to make a new hood for my roadster and used .062. The hammered and wheeled blister to clear the carbs was probably two inches tall. The blister is really thin on the top. It didn't split or crack and looks OK but I should have used .080 to prevent the thinness.
Ron
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Good information here, note the advantage of 5052 over 3003 in some applications and the minimum bend chart down at the bottom;
http://www.aircraftspruce.com/catalog/mepages/aluminfo.php
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We used 3003 and .062 but most of our panels are flat or have a gentle curve.
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Paul,
Give me a call.
New shop number is 772.210.2713. I would be glad to help.
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5052 .060 for most of my liner. 3003 only in a few spots. None was annealed during the process. Its got some nice curves I think
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And join www.metalmeet.com Panel Pounding Preacher out.
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Thanks for the comments and links.
We are looking to modify the front end and fiberglass is heavy and I hate the blisters in the paint from sun.
Sound like .06 to .08 is a good start.
The good thing is most of our panels will be flat with radius curves from a roller.
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...... and fiberglass is heavy....
Not necessarily a bad thing if you need help with the CG/CP,
Sumner
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I would highly recommend not to use .080, you can do a lot of forming with .062 . Bend stiffness goes up with the cube of the thickness so the .080 will be over two times as hard to bend and if you happen to use 5052 as Ed suggested it will be a real PIA!
If you are going to do any three dimensional forming, i.e. bubbles etc use 3003 H14 and anneal before forming. For panels that are formed without 3D shapes the 5052 is good, strong and very corrosion resistant.
All of the new panels on our little lakester are 3003/.062. Jim Hume used .071 for many of the panels on Marlos Target 550 streamliner but I think it was so after the body was assembled he could take and vixen file the body flat. That had to be a real job!!! but it does explain why it is so flat and perfect!
Rex
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Not wanting to be a smarta$$ knowittall, but having fooled around for 40 years or so with aluminum, the correct thickness is .063.
Otherwise, a lot of good information here. As always from Rex.
For wrap around bodies, 5052 and shapes, 3003. Flat panels, strength might dictate 7075 T-6 if it's structure otherwise 5052. (.032, .040).
Nobody I know likes to gas weld 5052, the joint is ugly gray. 3003 with parent metal or 1100 rod is proper. Get flux from folks like Tin Man Tech these days.
I've been too timid to again try welding with Hydrogen, it's super clean but I wasn't ever able to set the flame right. Oxy acetylene, I can see what I'm doing. If anyone out there has mastered hydrogen send me a PM if you're in the mood to have your brain picked.
Have not bought much 3003 (H 14) lately but having to wait from May to August for a sheet of.063 from Aircraft Spruce of all places I'm wondering if the pending tariffs have affected the market???
Hume might have chosen .071 (hard to find in 3003) anticipating the dynamic pressures found at 500 plus.
IB
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A interesting side note on Marlo's race car is that when Jim Hume started installing the body panels He set all the rivets (literally thousands with all of the inner support structure for the panels) about .040 (if memory serves) higher than the body panels and then filed each and every rivet down to make the surface perfect. Keep in mind this vehicle is only 42' long!
When Jim was doing the final fit of the body panels He was unhappy with the gap at the top of a ten foot long side panel so he bought a ten foot long strip of heavy gauge copper and clamped it behind the top of the panel. He then proceeded to tig weld a bead ten feet long and file it down for a perfect fit.
For anyone who has a chance to visit the Smithsonian Museum in Washington D.C., Some of Jim's Fabrege Egg's hand carved from multiple layers of exotic wood are (or at least were) on display.
Check out the Target 550 construction photos under Build Diaries on this site.
One Run Bob, out.............................................................................