Aluminum body panels...looking for REAL info

[Beezil]

I need to figure out what folks are using for thier aluminum body panels and an idea of the range of gauge.....

I'm wondering if there's one specific material type that's tried and true?

was looking at 5052......

this is going across the lower portion of the door openings on formed steel tubular ribs....the aluminum will be rolled with a slight 'cup' to give it strength for side-impact resistance.....

[Flowers]

Let's get this back on track.

Why 5052? Is it easily accessible?

I'd go for a 6000 series Al if you can get it cheap enough, although it's probably overkill.

Something in the 2000 series would be tight also, and cheaper.

Flowers

[Lincoln]

Back here they use 5052-H34 to build jet boats. I thought the 6000 stuff was too brittle, but I'm not an aluminum expert.

I do know that I've pegged rocks a few inches under the water (my boat need about 6" to run in) at 20 mph and it just left a few scratches. No cracks or big dents in the boat, but my passenger, that's a different story.

Hmm, maybe that's why he won't go fishing anymore.

Later,
Lincoln

[Mcstiff]

So your making AL rockers or boatsideing it?

[Weasel]

What's with all the drama....someone get sand in their panties???

Carroll Smith:
2xxx - require heat treatment and aging to reach optimum propeties. Mechanical properties can rival or exceed low alloy steel in heat treated condition.

5xxx - Very good welding characteristics and are reasonable formable. tensile values while moderate are the highest of the non heat treatable alloys.

6xxx - Stregth level less then 2xxx or 7xxx series these alloys are very formable and have excellent weldablilty. All require heat treating and aging to reach optimum strength.

7xxx - Formablilty is very poor and are only weldable by spot welding. Very high stregth but little ductility.

[Beezil]

sounds like 5XXX series is the best choice.....

[Flowers]

hmmmm. I've never heard of 6000 having less strength than 2000. Actually, I thought (that's what I get) they added 6 and 7 to the 2 to make it stronger.

Just use sheet metal!

[Beezil]

Like I said flowerchild, I was looking for real info....

there you go again with "i heard"

[Flowers]

If it's on the internet.........then it's gotta be true.

[DTHBOX]

2000 series and 7000 series aluminum are unweldable. 5000 's are soft. I have no experiance with aluminum body armor ,however as 6061 T6 aluminum is the stongest.

[KarmirXJ]

sorry to jump of track, but Im trying to do the same thing with mine, and i was thinking of using Steel, whats wrong with using steel instead of AL?

[Beezil]

weight.

[Beezil]

this is what I'm talking about....

all my tech books say that 6000 series is LESS strong than 2000 or 7000 series....2024 is supposedly the most widely used aircraft alloy. WE'RE TALKIN SHEETS HERE......not tube.

5000 series has a higher magnesium content, which results in its moderate to high strength rating depending on its manufactured hardness, for example, 5052-h32 (quarter hard) and 5052-h34 (half hard)

based on quick research, 5052 seems to be the best choice, gotta get some price quotes to see if h-34 is more expensive....

I think I'll go with .062 which I think will be adequate for a skin. If I cold-form it on the plate roll like I plan to, the "cup" in the length of material should resist impact much better.

[Flowers]

Your talking about 2- 3sq. ft. pieces of body panel. How much weight are you going to save using Al over sheet metal? 4-6 oz.

You need to stop reading POR.

[Beezil]

a comparison between 6101-t6 and 5052-h36

tensile strength.........................6101(32.0) 5052(40.0)
yield strength....................................(28.0) ..........(35.0)
elongation percent(.062)...................(15).............. (7)
brinell hardness.................................(73)..... .........(71)

source: Central Steel and Wire Company tech manual 1990

I have yet to make a cost comparison of these two alloys which would be interesting.....

[Beezil]

well flowers, you need to do more research before you charge me with reading too much POR....

.062 5052 weighs .88 lbs. per sq foot
.062 CRS weight 2.5lbs per sq foot

I have 19 sq feet of metal total

that's 47 pounds worth of steel
and 16 lbs worth of aluminum

it all adds up

[Flowers]

Get some quotes on a 2 and 6 series also, just 4 fun.

Flowers

[Flowers]

Damn! I had no idea. Maybe I should stop reading POR and just call you 4X a day with questions. Thanks for taking up your personal time and doing the research for me B.

19 sq ft.? I thought you were just covering the lower half of the door openings.

[Beezil]

i am....but some of the aluminum will be used for ground effects and a huge ass air spoiler for the back......

[Eagle]

Originally posted by Beezil
a comparison between 6101-t6 and 5052-h36

tensile strength.........................6101(32.0) 5052(40.0)
yield strength....................................(28.0) ..........(35.0)
elongation percent(.062)...................(15).............. (7)
brinell hardness.................................(73)..... .........(71)

source: Central Steel and Wire Company tech manual 1990

I have yet to make a cost comparison of these two alloys which would be interesting.....

Lemme see if I understand this: You're worrying about tensile and yield strength for a door skin that will never be exposed to tension until you slide sideways into a rock, in which case you're going to exceed the tensile strength rating of any known alloy of aluminum, steel, or other exotic metal. Does that about sum it up?

Just head over to Lowe's and buy a sheet of whatever they have in the rack.

[Weasel]

Apartently 5052 is hard to find and not cheap. 3003 is cheaper and not that much weaker. Also when you get into the 5052H36 your going to have a brittle piece of metal, not something you want for a door skin.

Based on what you want I would look into 3003 H-16 series.

And 6061 T6-T651 is not the strongest alloy aviable.

[Flowers]

Originally posted by Beezil
i am....but some of the aluminum will be used for ground effects and a huge ass air spoiler for the back......

I did the math. If you locate the spoiler just behind the rear window of the chop, it will only affect your anti-squat by 10%. Although, the spoiler cannot be "huge ass" it must be < 5 sq. ft.

Hope this helps,

Flowers

[Beezil]

eagle, I'll be exposing that panel to tension the first five minutes i get on trail....

not so much as a concern as flying shopping carts though...gotta protect the poseur rocket.

weasel, thanks for the reply...

the specs on 3003 looks kinda pathetic though....

tensil 26.0 yield 25,000lbs/sq/in elongation 5 (%-2" in .062) and a brinell hardness of only 40........

the price ballparks close to similar, availability isn't a concern, i can get pretty much any material I want from a number of vendors.....

I wish I could sample some drop-off........

what do you think, i'd love to hear it!

[Rev Den]

[i]I wish I could sample some drop-off........

what do you think, i'd love to hear it! [/B]

I think that is your BEST idea...get a couple sq ft of each, and beat the hell outta it for a while...see what works. It may be low tech, and I do not have your knowledge, but that is where I would start. Also...you may have thought of this...but ask at some of the Race car shops in the area.

Rev

BTW For ground effects I would recommend a more flexable material to handle the potholes of the city streets.

[Weasel]

3003 has a yeild of 21ksi at H14 which is 7ksi less then the 5052 H32. But it is much more formable and fatique reistant then 5052. It's probably going to come down to price and avalablity now. Carroll Smith state he only would use the 5052 in the H32 form, I'm assuming because of the brittle issue with higher treatments. My chart lists 3003 as having an Ultimate tensile strength at max heat treat of 30ksi and a minmum tensile stregth annealed of 16ksi. 5052 is 39 ksi and 28 ksi for the same cat. Another alloy I see listed that may work is 3004. Rated at 41 ksi and 26 ksi for the same cats above. The only thing is I don't have any information on how it well it forms.

6061-T6 may also be an option and it's properties are quite a bit better then either 3003 or 5052 it's just a bit harder to from.

The reason I'm not jumping allover the 5052 is because I'm pulling my information from Carroll Smith's book Engineer to Win and he doesn't seem to talk alot about it. Except he would use 3003 instead of 5052 and he use 6061-T6 because it's the strongest alloy he says that can be bent over a block with a sandbag and hammer.

You may want to check into 4130 sheets or similar. You would have to run the same thickness (maybe .035 or even .025) and still come out ahead on the strength issues with out much weight.

[Beezil]

thanks, that's great info.....

I'm wondering if carroll smith encountered availabilty problems with 5052 as a reason he omits any info on the alloy in his book

I will be giving 3003 a good look....

I know this might seem like a needless thread for most, but for me personally its something I don't know about, and learning something new is fun, so eat me you people

[Weasel]

thats what I was thinking...to hard to get and probably to expensive (5052)

[rixXJphx]

Just a couple of thoughts:

1. The weight savings of aluminum vs. steel were based on equal thicknesses.
For equal strength, rather than 0.060 steel (~16 ga), a thinner steel (~ 20 or 22 ga) would work. Therefore, the weight savings-to-strength ratio would result in a savings of about a 44 lbs instead of 88.
Sorry, I haven't run the numbers; and, it would depend on which steel was used (33 ksi and 50 ksi being the most available).

2. Though the panels are short, there's a possibility of temperature deflection, winter-to-summer, when aluminum sheet is secured to a steel frame.

[Beezil]

20 or 22 ga) would work

hey guy, thanks for the reply, i appreciate it....

I want you to know that so what i am about to say doesn't come across like I'm a fat jerk or anything....

I am a metal manufacturer by trade, but the limit of my experience ends with steel.....

at the moment, I probably have on hand thirty or fourty TONS worth of steel, some of it is 20 and a little of it is 22 gauge. I have first hand experience working with it, which I believe qualifies me to ask this question:

are you freakin nuts?

20 gauge?

22 gauge?!!!!!!!!!!!

I know you are probaby not clairvoyant, so you probably don't have a good idea what it is I'm doing, but both those gauges are barely enough protection against twigs! I could take a screw driver and punch a hole right through 22 ga crs! how could you come up with a suggestion like that for my application? YIKES!

:eek:

[4ward]

Yeah, this thread is pointless in a jeep needs way. It's good tech as far as material strengths.

I don't understand why you're worried about the strength of it. Unless you're going to run .25" thick it's going to be punched, bent, and mutilated no matter what. I'd find the cheapest and easiest to bend and go with it. That way it doesn't crack and break when you go to beat it back into shape. Have you looked to see what the JP aluminum bodies are made of. They are easily worked back into shape and seem to hold up decently.

[Eagle]

Originally posted by Beezil
... at the moment, I probably have on hand thirty or fourty TONS worth of steel, some of it is 20 and a little of it is 22 gauge. I have first hand experience working with it, which I believe qualifies me to ask this question:

are you freakin nuts?

20 gauge?

22 gauge?!!!!!!!!!!!

I know you are probaby not clairvoyant, so you probably don't have a good idea what it is I'm doing, but both those gauges are barely enough protection against twigs! I could take a screw driver and punch a hole right through 22 ga crs! how could you come up with a suggestion like that for my application? YIKES!

:eek:

I don't claim to have any idea what you plan to do with this. What you SAID you were going to do with it is skin a door. Boor skins are generally 20 gauge or 22 gauge steel. Now, if you're really talking about making this into a stressed skin panel, you should say so. If you're concerned about penetration protection (just what are the brothers carrying in your 'hood these days, anyway?), call up a local armored car company or limousine company and ask what they use to ward off RPGs.

Sorry ... I'm honestly not trying to be a wise-a$$ here, but for a stinkin' door skin I just don't understand all the concern about tensile strength and such. Door skins are skins, that's all they are. They are generally not structural. Why is yours otherwise?

[Eagle]

BTW --

One thing to remember about most tempers of aluminum is that they work harden almost immediately. One bend is usually all you get. Try to bend it back and it breaks.

[4ward]

Can't find anything about the jp bodies other than they are made of marine grade. So, I believe that was covered on the first page of this oh so informative thread.

The comp and hardcore guys are having good success in getting their rigs looking good again with some hammer and dolly work. I'd investigate this farther.

[Beezil]

this is going across the lower portion of the door openings on formed steel tubular ribs

here, I'm quoting myself.....

I know its not a very complete picture, i should have been more clear......"door openings on a tubular frame"

openings...........means no doors......I didn't remove them myself....a tree did it....

so I'm building a tubular-reinforced side panel to protect my ass in a lay-over is essentially what I'm up to.

[Beezil]

"marine grade" comes up in the description of both the 5000 and 3000 series, actually, the 5052 which is what I wanted to go with, but it also comes up as a description of that weez was suggesting with the 3003 (thanks again weez)

Yeah, Weasel, it'll probably will come down to price point.....I'll hafta ask "what would you pick" questions with a couple of my vendors.....

[Lincoln]

You guys get this figured out. I still want to replace my cross member and skid with aluminum. :)

You might also check out the anti corosive (can't spell) properties. I think that is where the "marine grade" label comes in. There are several boat mfg's around here that use some different grade. I don't know what it is, but salt from the roads with discolor and pit the heck out of it.

You don't want to have to polish it after every trip to the mall.

Later,
Lincoln

[rixXJphx]

Originally posted by Beezil
are you freakin nuts?

20 gauge? 22 gauge?!!!!!!!!!!!

.... so you probably don't have a good idea what it is I'm doing, but both those gauges are barely enough protection against twigs!
No offense taken.
Nuts is nice sometimes, that's when the best ideas flow! :D

Seriously, I agree that your-originally indicated 0.060 inch (~16 ga) steel IS more appropriate to your armor needs. I wasn't aware of how much penetration resistance you desired.
I've used 16 gage steel roof deck for rifle ranges (in addition to internal armored baffles). Tests proved 1) a .223 would penetrate the 16 gage steel 2) the bullet lost so much energy that its descent was *nearly* harmless.

However, the main point of my original post remains:
That for comparable strength performance (whether as a skin or as penetration resistance), aluminum MUST be thicker than steel.
Therefore, the comparison should be 0.060 steel (47 lbs) vs. ~ 0.090 aluminum (24 lbs).
The weight savings isn't the original (47-16=) 31 lbs that you calculated, but rather about 21 lbs.
Agreed, that's 21 lbs saved (or placed elsewhere on the rig).

Best wishes on the rig.
-Rick

[Weasel]

Any of the 3003, 5052, 6061 series are all excellent in corrosion reistance so that should not be a problem.

Somone already mentioned it but I am going to start looking into ways to get some alum or composite skids.

[rixXJphx]

Pound for pound, laminates are the strongest sheet materials.

If ya took a LOT of aluminum license plates and kind of overlapped them in layers with some epoxy and pop-rivets..... :D

[Beezil]

one ton,

not only did I draw it, but today I'll need to program a few lines of code for the cnc tubing roller!

[CRASH]

Have you looked into titanium sheet? Seriously (for once).

You could through-bolt or rivet it to your fancy tubing and have submarine like toughness at aluminum weight. It's not as expensive as it used to be, either. I'm keeping my eye open for a sheet to protect my buggies tender underbelly.

CRASH

[Rev Den]

Just as a thought....if Beezil turns it into a buggy....is it still an XJ???

At what point does it cease to be an XJ? Just a point for debate.


Rev

[FatXJ]

I have to correct something here 7000 series is weldable. There are special steps needed to make it strong but it is weldable.

[Weasel]

I'm sure you can weld anything but comapred to the other alloys 7000 is a very poor weldable alloy.

[DTHBOX]

Tell it to the FAA that 7000 is weld able. Makeing it stick together and welding are two different things.

[Beezil]

DTH, thanks for watchin out for me, but sean and I bust each others chops, both publically, over e-mail, as well as face-to-face......even though his come-backs are lacking, its just for fun, another form of metal bitch competetion!

He told me in the form of a constructive critique that the "s" form of the door opening does not match the lines of the cherokee, and looks out of place.....I think he said "it sucks" or something as well, which is "polite" compared to the rippings I got in art grad school, so i can deal with the process and subjectivity of critique.

I have to agree with him, straight angles would probably be more appealing, but from a fabricating standpoint, too easy....

somewhere in the middle would be the ideal thing.

But then I was reminded that Moab is around the corner, and since my XJ is still on jackstands without any suspension connecting the unfinished axles, and no crossmember to support the drivetrain, and no exhaust or fuel lines for the motor, and no brakelines to stop the thing, I probably was not prioritizing effectively......

he *might* be right about that, but he's still an asshat.

[4ward]

He can't put his axles under it, one of them is a 6 hour drive away from the other one.

I do consider his 1st rendition of the door openings to be pretty much butt ugly, wasn't going to make it public knowledge unless he did though.

You wanna get complicated with straight angles? Make the skins match the roll of the body and make it all look correct and like it came that way from the factory. I wanna see what you do with your b pillar to keep it from looking like ass. That is, if you feel the need to keep a b pillar.

[Beezil]

sean, just so you know, I don't need the other axle.....

I can run the 37/5.38 combo up front with the 35/5.13 combo in the rear, same relationship.

I might even find this is the secret to surmounting the waterfall on upper helldorado.......

How much would you pay me to show up to moab like that?

that would be funnier than hell.

[Lincoln]

I'd definately give you a Lucky Logger.

Cheapest beer I could think of. :)

[GSequoia]

Screw that, I'll give you a Guiness for that!

[Fore Wheeler]

then you could blame you mom for changing your tires fer ya

[FatXJ]

Originally posted by DTHBOX
Tell it to the FAA that 7000 is weld able. Makeing it stick together and welding are two different things.

Like I said SPECIAL processes are needed to weld it to make it strong. Dry welding the 7000 series will make it weaker at the weld. Dipping the aluminum in a special acid base will displace all the air in the material and will allow the weld to to penetrate and harden without weakening the material around it. It is the air in the aluminum that causes it to be weak and hard to weld.

Bicycle manufacturers have been using 7000 series since the mid nineties and they quickly learned that those frames had a higher rate of failure so they changed their process of welding 7000series to compensate since 7000 series is a far better frame material than 6000 series. The FAA is the organization that pretty much got 6061-T6 designated as Aircraft grade aluminum. Who cares if aircraft use it? Use of a material is application based not aircraft based.

[mbryson]

Originally posted by Fore Wheeler
then you could blame you mom for changing your tires fer ya



BAAAAAAAHHHHHAAAAAAAHHHAAAAAA

[ChEwBaCcA]

Beezil, Why not do it in Lexan? Ill bring over the infra-red and we can bend up some bullet proof panels?

Chewy

[Ed A. Stevens]

Beezil, you did the research, build it.

5052-H32 (quarter hard) is easy to bend with standard sheetmetal brakes and presses. The stiffness is similar to annealed steel. It is much stiffer than annealed 6061-T6, and cannot be reheat-treated like 6061. Availablilty should be simple as it is a standard sheet metal stock item.

I built considerable lengths of 5052 ductwork (and custom items) for the Jet Propulsion and Rocket Propulsion Labs at Edwards AFB in my youth as a Union sheetmetal worker. It works for boats and cars, and is weldable. I even got to sit in a Gurney AAR Eagle that once placed at Indy, with a monocoque made from 5052.

2024 is great for hardness, but it also deteriorates with age. I found this out helping with some rebuilding work on the main spars of a P51. the 2024 crystalized. If you plan for the XJ to last 40 to 50 years ;) it may not be the best choice.

Get out there and build ...

[Safari Ary]

What are street signs made of?? They seem to take abuse pretty darn well on my friend's recreational buggy....

[old_man]

I like 6061-T6 and have worked with it for years. It should be readily available at any metal supplier. You have to be a bit more careful bending it, but it is pretty strong for the weight. It also has pretty good corrosion resistance. Its about as strong as you are going to get out of aluminum without going exotic.

Most body panels could easily be .060" with .090" being the next kind of standard size up from there.

Oh, and remember if you are going to paint it, use a zinc chromate primer, otherwise most paints other than Hammerite just won't stick for long.

[Matt S.]

Hey tom... you know this is 2 years old?

Good info, but haha. Old.

[old_man]

I think the reason it got moved over here is that it is a classic thread about material selection. The info is as relevent today as it was two years ago. You will be seeing lots of good older threads being moved here for reference.

[Matt S.]

:) :) :) :) :) :)

Good. Just seemed odd.

[woody]

I was thinking the other day about composites... strength vs benefits vs weight vs cost vs longevity... in a 'hillbilly armor' role.