Black "poop" Pipe Cage

[XJoachim]

Sorry, a cage should attach to the frame or some sort of frame. Then it may extend to bumper, fender and sliders. The main thing is to secure the passenger area, if you tie it in your bumper like an exo that is to protect a bit of sheet metal. This is usually just an extension of the cage and not that critical.

 

[5-90]

Don't worry - I wouldn't use pipe for bumpers and such, either - not on a vehicle.

Any safety device deserves the best material you can get! In pretty much every case, that means material that was designed to take sudden loading when used structurally.

The ideal design for a cage would be one where the body could literally disintegrate around the cage, but the cage and its occupants would still be intact. The seats, ideally, would mount to the cage - as well as driver restraints - and the rest of the vehicle would be designed around it.

In our case, a number of compromises must necessarily be made - including using the lower part of the unibody to tie the lower part of the cage together (a good cage would have a "halo" bar, which could be screwed/welded to the upper unibody surround.)

Where you are forced to compromise in structure, you make up for it with material. End of story.

Call me cranky, but I've become attached to all my parts, and I'd like to keep them where they are (even the replacement parts...) Weight is not seriously an issue for us, so we should use the best we can get our hands on.

Besides, in strength/weight ratios, you'll do better with Cr-Mo steel than you will with pretty much any metal pipe. Save your money, and do it right later. Take it easy in the meantime.

5-90

 

[BrettM]

Just my .02

I work with black pipe all day long and by no means would I ever use it to protect myself or my investment. Most of the sch40 in my area is now shipped in from other countrys and isn't worth the money we pay for it.
When you can take 1" sch 40 and bend it over your knee it should tell ya something.....

now that is some ghetto-ass chinese pipe :shocked:

I used 1" sched. 40 for my "tube bed" and it's dragged on a number of rocks with no denting or bending, just some scuffing. of course I'm using good pipe...

 

[AZTurtle03]

MY XJ ADDICTION... I would be willing to bet that you couldn't bend 1.25" SCH40 pipe over your knee. Unless you are like Lee Priest or someone of that sort!

On the subject of pipe... Surely it is not as strong as tube... and it may fail... However... If your decision is PIPE or NOTHING, then I say run with the pipe!

Turtle

 

[xuv-this]

my .02- decent size pipe could potentally work well for a cage. if the cage is designed and assembled correctly (good fat welds with the right rods by someone who knows what they're doing) it would be fine. you could build a cage from angle iron if you designed the triangles into it right. the key is to make the cage so it will pull on itself. the problem is that you need to know what you're doing to do this. and if you do know what you're doing, you're probably going to realize that the extra pipe used would offset the weight/cost, and would want to do this the more expensive way.

 

[boynamedsue]

dont use pipe. i mean come on this your safety were discussing here do you realy want to risk injury just to save some $$$. if you want a good cage check out www.dandcextreme.com he uses 1.5''.120 wall hrew, and it fits awesome, strong as hell too. it sells for about $450 plus shipping . i've never seen someone break his products.

 

[Roxtar]

I wouldn't use it on anything.
Why would you go through all the labor of making a cage, bumper, or whatever, and use poor quality materials. I'm not saying you need to use DOM but at least go with HREW.
As much work as fabbing a cage is, don't you want to never have to do it again?
Don't you want to KNOW it'll work?
Even more so with smaller jobs like bumpers or sliders where the material cost difference is far more insignificant.

 

[TrailHunter]

The process of "drawing" is pulling a (formerly) solid form over a mandrel of some sort to get a hollow shape - and it is done on materials that are too hard/stiff to work with extrusion (aluminum can be extruded, since it is relatively soft. Steel is drawn - which actually results in less stress on the die and mandrel.)

If the "drawing" process is done with a proper die and mandrel, you will end up with a seamless shape - the "fingers" retaining the mandrel are placed several inches back to allow the material to close within the die after passing. There is still a seam, of sorts, but it's not a welded seam - which means there is no change in hardness/strength, and there is no stress riser due to the HAZ. Therefore, DOM can be considered "seamless" for all but the most critical applications.

If it's rolled/welded, it's rolled/welded. If the tube is drawn over a mandrel then welded, it's still welded tubing. It is possible to force a mandrel through a welded tube to gain a clean ID, but you will still have the HAZ and the attendant stress risers - unless the entire section is then re-heat-treated.

I hate to belabor a point, but BrettM is right about DOM. Mild DOM usually DOES have a seam. It is a welded tube that is then run through a mandrel which creates wall thickness uniformity and it's formed cold which adds strength. What you're describing is a process called extrution. That's how true seamless tubing is made.

In case you think I'm wrong, here's what Google's definition of DOM tubing is, http://www.google.com/search?hl=en&hs=p6k&lr=&c2coff=1&oi=defmore&q=define:DOM+tubing

Back on topic. I have never built anything using pipe, nor do I know anyone that has so I can't speak on the subject.

 

[RWKHausSupply]

FYI 4130 chromo can be had in so cali for only 4.55 per foot in a 1.75 x .120 wall! AND DOM 1020 for only 3.10 per foot both price includes Delivery! hell in 1.5 x .120 is under 3$ per foot!

Pony up the extra posket change and find a friend with a bender if you must! Daym what is like 40$ extra for tubing!?

 

[racer32]

Just out of curiosity, How many people here have built something out of pipe and had it fail?

 

[Roxtar]

FYI 4130 chromo can be had in so cali for only 4.55 per foot in a 1.75 x .120 wall! AND DOM 1020 for only 3.10 per foot both price includes Delivery! hell in 1.5 x .120 is under 3$ per foot!

Pony up the extra posket change and find a friend with a bender if you must! Daym what is like 40$ extra for tubing!?

My point exactly.
Yes, you can make something out of cheap material and you may even get away with it but why would you want to?
As much work as these projects are, why would you use a sub par material that may or may not fail when it doesn't cost that much more to do it right?
I would hope that the pride of doing the job right would be worth it alone.
A serious case of penny smart and dollar foolish.

 

[RWKHausSupply]

Just out of curiosity, How many people here have built something out of pipe and had it fail?

ok thats a trick q.. a few reasons..

Those of us that are going to actually use the cage and do, know better then to skimp the very little additional $ for a true DOM or 4130 cage.

And those that do build a cage out of the laughable sch 40 pipe I doubt would show the related damage that occures after such a roll if it happens.

Given here at the mechanical design install and engineering firm I am employed at, we do use sch 40 not only for large pipe needs for water, chilled water, cond. water, and hot water, but yes even for pipe stands to support the product conveying pipe. So as it may be used for "stuctual" use its not for high stress applications.

Ever read any or all the rule books you can/could regarding cages or approved materials for cage work???

 

[TrailHunter]

I think everyone knows that you don't need to jump off a skyscrapper to know it's bad, but what he's trying to ask how many people have seen a pipe cage fail. I think it's a pretty good question, but it's not very usefull consider that most cages are built with tube and they have failed.

Are there any engineers that can tell us the physical differences between pipe and tube assuming similar wall thicknesses? Are they different allows, are there different grades within the same allows. Is the MFG process different? Or is like BrettM suggested and that quality pipe is the same price as ERW?

 

[RWKHausSupply]

Well I can say that Company price for sch 40 black PIPE is currently $1.68 per ft and weights in at 2.72lbs per/ft for 1-1/2 that has a 1.9" OD and 1.6ID @.145 wall thickness that is in a type E with 36(ksi) min yield stress rating and a 60(ksi) min tensile.

Same in a 1020 DOM is at 3$ per ft in 1.5x.120 wall and is 45-85 (most being at 65-70) yield strength, and 60-95 tensile with most being at 90. Wieght is at 1.76lbs per/ft.

so its lighter and a average cage would be in the range of 80-100ft and be a whopping 117$ more and wieght 86lbs less. Thats the obvious points. Now for the elastistic properties and the hardness differences, I am not currently able to quote those with out some guessing so I wont.

 

[xuv-this]

sch 40 black PIPE is 2.72lbs per/ft for 1-1/2 that has a 1.9x.145

Same in a 1020 DOM is at 3$ per ft in 1.5x.120... Wieght is at 1.76lbs per/ft.

so its lighter and a average cage would be in the range of 80-100ft and be a whopping 117$ more and wieght 86lbs less. QUOTE]
just to clarify on the weight, you are comparing 1.5 to 2" dia. tube
i don't know of anybody that runs a cage out of 1.5" tubing. mabye you can do the math on the weight per volume of metal used(i'm too lazy right now) i'm pretty sure that DOM is denser. the main physical difference between the two kinds is that poop pipe isn't as dense because it isn't nearly as pure, in addition to being a different alloy and different manufacturing processes. that's where the price and strength difference comes in.

 

[racer32]

...1-1/2 that has a 1.9" OD and 1.6ID @.145 wall...

...you are comparing 1.5 to 2" dia. tube...

Nope...

Pipe = I.D
Tube = O.D.
-----------------------------------------------------------------------
these are all stolen from Pirate...

rolled pretty hard from about 6 feet high onto granite last weekend. only piece of DOM on the cage is the only piece of metal(besides sheetmetal) that was damaged, all the POOP pipe is intact no cracked HAZ on welds....

Pipe exo-cage on probably a 4,500-4,800 lb truck. 25mph down a hill. Rearend started stepping out, then the truck went kind of end over end sideways for two full rotations. Very hard impact. No broken welds, just minor bending. He and his wife walked away. He had also rolled his previous truck with a pipe cage a couple of times without a problem.

 

[BrettM]

I am going to be making my cage soon, and it will be a combination of 1.25 Schd 40 PIPE (1.66 OD) and 1.5 .120 wall tube. I am going to use the pipe on the areas that will be dragging on rocks because of the thicker wall and more resistance to denting. The only reason I'm even going to use tube is for the weight savings on areas that won't be contacting rock frequently.

I spent about an hour BSing about pipe, HREW and DOM with the guy running my local steel shop (Valley Steel if anyone cares). He made several calls to his suppliers and even the actual steel manufacturers, and he found that the HREW and DOM are rated within 2% in strength, and the HREW and pipe are made using the exact same steel and processes, just different dimensions and not officially rated.

The only pipe cages you will see fail are the ones very poorly designed or with very poor bends from using a crappy bender. Same steel, same process, quit bitchen already.

 

[BrettM]

I hate to belabor a point, but BrettM is right about DOM. Mild DOM usually DOES have a seam. It is a welded tube that is then run through a mandrel which creates wall thickness uniformity and it's formed cold which adds strength. What you're describing is a process called extrution. That's how true seamless tubing is made.

In case you think I'm wrong, here's what Google's definition of DOM tubing is, http://www.google.com/search?hl=en&hs=p6k&lr=&c2coff=1&oi=defmore&q=define:DOM+tubing

Back on topic. I have never built anything using pipe, nor do I know anyone that has so I can't speak on the subject.

correct, 5-90 is describing Cold Drawn Seamless, not Drawn Over Mandrel, from Chicago Tube

DRAWN OVER MANDREL has very little wall variation and no spiraling eccentricity. The tube is formed and electric resistance welded from flat steel which has very little gauge variation. Any wall variation that may exist in the flat steel runs in the same plane throughout the length of the tube, leaving the bore straight and true.



COLD DRAWN SEAMLESS has an inherent characteristic of eccentricity. In the piercing process a solid billet is heated and forced in a rotary motion over a piercing point to form the seamless tube hollow for subsequent cold drawing. It is impossible to keep the piercing point always in the exact center of the tube round during the piercing operation. As a result, wall variation is induced into the tube. Moreover, since the shell is turning as it is being formed, spiraling eccentricity is created. Additional hot and cold finishing operations greatly refine the dimensional accuracy of the seamless tube, but the eccentricity is never fully eliminated.

 

[racer32]

I spent about an hour BSing about pipe, HREW and DOM with the guy running my local steel shop (Valley Steel if anyone cares). He made several calls to his suppliers and even the actual steel manufacturers, and he found that the HREW and DOM are rated within 2% in strength, and the HREW and pipe are made using the exact same steel and processes, just different dimensions and not officially rated.

The only pipe cages you will see fail are the ones very poorly designed or with very poor bends from using a crappy bender. Same steel, same process, quit bitchen already.

Well put Brett. I have run pipe cages in 3 different hobby class racecars and have taken some serious hits and never had a failure...

 

[racer32]

and just for the record, I dont care what you build your cage out of; But if you build it like this you need to sell your tools and buy a Geo Metro...