Poor man's cage material

I'm in the design stages of my 65 Scout build. Its going to be 90% DD and 10% capable off-roader. Much of the body is wasted so I plan on keeping the front end and building a flatbed/cage for the back. The cage will have angled runs from the back up to a main hoop, then forward to a windshield hoop, and (if practical) a couple forward runs to the frame in front of the firewall.

The cage needs to be safe, but not anything race-prep or conforming to any rules. Given the type of off-roading i do and the amount that I do it, roll-over would be incredibly rare, but if it does happen I don't want to be squished. My idea of off-roading is rough dirt roads with the ability to use it like a tractor pulling logs and such. Roll-over is something that would be extremely rare.

What material should I use for the roll cage? Wall thickness? Diameter?

I was going to suggest PVC but that doesn't really meet your "safe" qualification.

3"x3" 0.25" wall square tubing.

Like this truck.

In reply to EvanB:

I thought about those foam pool noodles, but they might flop in the breeze :)

curtis73 wrote: In reply to EvanB: I thought about those foam pool noodles, but they might flop in the breeze :)

Your noodles flop in the breeze? Must suck getting old.

Dude... my noodle doesn't flop in the breeze, it drags on the ground.

Some girl asked me once to hit her hard and give her all 12". I said "bitch, I don't fold it in half for anybody."

But seriously... I'm actually hung like an infant........

and by that I mean 9 lbs 12 oz.

curtis73 wrote: Dude... my noodle doesn't flop in the breeze, it drags on the ground. Some girl asked me once to hit her hard and give her all 12". I said "bitch, I don't fold it in half for anybody." But seriously... I'm actually hung like an infant........ and by that I mean 9 lbs 12 oz.

4,000 lbs and not much in the way of factory protection - 1.75" x .125 erw or dom. Don't squash your other noodle.

If you go over onto the rock crawler forums, like Pirate, you'll see lots of information on home built exoskeletons and the like. Make from galvanized pipe, wood, and everything in between. There's a lot of good information over on that board, well hidden between the trash talk and the idiotic gibberish.

foxtrapper wrote: There's a lot of good information over on that board, well hidden between the trash talk and the idiotic gibberish.

So, what you are saying is that it is on the non-GRM part of the internet?

I'd think that if 1.75x.095 DOM can take a barrel rolling 3500lb race car at 150-200mph and keep the juice bag inside unharmed it ought to be able to withstand a scout tipping over at 5mph so... that is a pretty common stocked item at the metal store and not overly expensive. 1.5x .120 DOM is a little heavier and fits in a tighter space with the same strength.

For me the decision point is "What size do I have bender dies for" since those are a $300 problem.

Why not find an old dirt track car that has a cage? I've seen rollers go for less than scrap weight because no one wanted to deal with them. A lot of dirt track guys seem to park their old car for use as a parts car, but never actually take anything but the engine and transmission out. I've seen bare chassis go for under $100, so keep an eye out. Lots of metal in those that you can reuse.

Derick Freese wrote: Why not find an old dirt track car that has a cage? I've seen bare chassis go for under $100, so keep an eye out. Lots of metal in those that you can reuse.

+1 in fact i know of several just sitting one thay cut the fram rail out of so it just the "cab" Where you at now? I think PA but info says TX

DOM is usually about twice the price of ERW tube, and the strength increase in not real significant. Design and weld quality will have way more to do with it failing, or surviving being used. 1 3/4 12 gauge (.106 wall I think) is what I have used- it guarantees an .095 wall thickness. Funny how mill tolerance is always in favor of the mill...

two words: chrome moly
=]

Use SCCA cage requirements for material/ diameter/ wall thickness per weight of vehicle, it's prolly overkill for a low speed offroader... but it's safe. YMMV

http://sports.racer.net/docs/rules/2002/sect_18_roll_cage_and_chassis_2002_gcr.pdf

A lot of dirt track cars have really sketchy cages made of anything they can find cheap, even iron pipe. You don't want pipe, you want tubing. Iron pipe will just fracture. Also I bet the tubing in a dirt track car is too short, you're going to want a nice tall main hoop and your down bars will be longer than a car's.

I second the 1.75" x .095" or 1.5" x .120" ERW tubing recommendation. Buy or borrow a bender and learn how to make a cage!

No idea what its made of.

dculberson wrote: A lot of dirt track cars have really sketchy cages made of anything they can find cheap, even iron pipe. You don't want pipe, you want tubing. Iron pipe will just fracture. Also I bet the tubing in a dirt track car is too short, you're going to want a nice tall main hoop and your down bars will be longer than a car's. I second the 1.75" x .095" or 1.5" x .120" ERW tubing recommendation. Buy or borrow a bender and learn how to make a cage!

Pipe is bad, even our rinky-dink short tracks are wise to it and ban it. That doesn't mean that it never gets through. The only pipe that may pass off as tubing is 1-1/4" which is 1.66" OD... close enough to 1-5/8" OD tubing. Other pipe OD isn't even close to nominal tubing size.

modernbeat wrote: 3"x3" 0.25" wall square tubing. Like this truck.

I am totally gay for this truck. Yes it is clearly a male truck.

N Sperlo wrote: No idea what its made of.

You can tell what the welds are made of, though! Boogers!

corytate wrote: two words: chrome moly =]

No. Unless you are going to heat treat the whole thing after you weld it, a waste of money.

Personally for a cheap cage off road I would use either the ERW tubing or the 3"x3" square as suggested earlier.

dculberson wrote:

N Sperlo wrote: No idea what its made of.

You can tell what the welds are made of, though! Boogers!

I am amazed how many people can't be bothered to learn a little craftsmanship - especially when it's a safety item. I once had a well-respected muffler guy do a sidepipe for me. I had better skills that that guy over the course of my first semester in trade school. This guys been welding for 20 years and can't do a nice job.

I think ERW would be fine for you application.