Black "poop" Pipe Cage

[THRASHER]

I am sure some of you saw this thread on pirate about the guy who flopped his runner after using black pipe to build his exo....

http://www.pirate4x4.com/forum/showthread.php?t=342992&page=1&pp=25&highlight=poop+pipe+cage

IIRC BrettM is also using this stuff on his MJ after he took the bed off...

I know it isnt as strong as dom, but I think that it would be better than nothing in a rollover....what do you guys think, anyone had any experiences with this stuff.....

to a college student, at 99 cents a foot and bendable with a $99 HF bender this looks like a good material to use for a cage....any opinions?

 

[AZTurtle03]

Surely pipe is not as strong as DOM. However, you are right that the price sure is pretty to a student! I know as this is what I did.

I used pipe in my TJ to add to the factory rear half of the cage. The way that I looked at it is that it may not be safer then tube, but it is certainly safer then what is there from the factory. I took it all the way down to the floor and plan to bring it to the frame next month.

I think if it is all you can afford, then definately go for it. It is definately stronger to use pipe then to have nothing at all. However, I would also suggest saving your pennies so one day you may get a tube cage.

Turtle

 

[goodburbon]

man those guys on pirate are #$%ks, just blasted the poor guy up and down for building a cage out of pipe.

I had never been there before.

IMHO, and I worked with pipe several years, i1 1/2 inch sch40 pipe would be fine for flops, and skidding, and protecting the body at large. if you get into an extreme rollover situation they all bend, and its better than nothing. it is heavy though.

 

[AZTurtle03]

On the weight issue... if you compare 1.25" Sch40 pipe (ID - 1.25" OD - 1.66") and HREW 1.75 .120 wall tube the pipe weighs 2.2lbs/ft where the tube weighs 2.1lbs/ft. Not enough of a difference to make a big issue I don't think.

Turtle

 

[Ludakris]

Huh, havent seen any red letter responses yet...


I'll sit back and wait.......

 

[Jes]

Huh, havent seen any red letter responses yet...


I'll sit back and wait.......

As has been shown in the past, people will do what they want despite the good advice they receive.

 

[1990XJ4x4]

Well i guess a Pipe cage would be better than nothing. If it is well designed and fabricated, it could hold up better than a poorly designed Chromo cage. I havent started building a cage for mine yet because I am still in the process of learning tube chassis design and anylisis. Even though I will be designing a small mini baja car made from Chromo tube, the process of anylisis and design will be similar. In short, design it well and you can come out with good results.

 

[BrettM]

Yes, I use some on my bed, not for a roll cage.

http://img48.echo.cx/img48/2482/img0688resize7fm.md.jpg

If you use good pipe, it has basically the same properties as HREW tube which many people have no qualms about using for cages. The 2 major complications that arise are (1) cheap chinese crap pipe. If you're finding pipe for a buck a foot, I can almost garauntee that it's crap. I was paying $3/ft for good pipe in the 1" schd 40 size (1.31" OD). And (2) bend quality. When you use a HF pipe bender it flattens or even kinks the bend. When you use a tube bender like a JD2 it keeps the cross-section of the tube circular through the bend.

I pipe cage can certainly be made that will withstand many rollovers (I've seen many of them) but it will be heavier than a DOM cage of similar strength. Either way your design is HIGHLY critical.

 

[Mr.OverKill]

i like the idea that any cage ( designed well ) weather out of DOM or Pipe is better than no cage at all. but in all seriousness, safety is first and if you cant afford a tube cage but you can a pipe one ( i know i might get some s#1t for this) dont go wheeling and save the extra gass money you would spend untill you get enough for the tube. THEN you can giter dun right

 

[BrettM]

good pipe costs just as much (or more) than HREW tube. it's the bender that is so much cheaper, and of course the worst part of a pipe cage. make friends with someone with a tube bender, find some people in your area making a large tube order, and it will be cheaper and better than pipe. that's what I'm doing.

 

[THRASHER]

good pipe costs just as much (or more) than HREW tube. it's the bender that is so much cheaper, and of course the worst part of a pipe cage. make friends with someone with a tube bender, find some people in your area making a large tube order, and it will be cheaper and better than pipe. that's what I'm doing.

I think I am going to do just that....in the process of moving up to chico and my roomate up there is tubing is runner right now so I will have access to a bender in a few weeks....

 

[badron]

There only one problem when using 40. You can't really come back and bitch because it not to be used for this kind of thing. Pound for pound is just fine. Been using it for over 30 years. As soon as someone rolls a poorly welded, badly fitted, improperly design cage and it comes apart they say "next time I will use a better pipe" BULLSXXT Most third party people don't use 40 so when someone try to sew them. They have there butts covered by using the "right pipe"
Use it, it's strong cheep, and right down the street at the hardware store.

 

[XJ_ranger]

id love to use pipe, then i wouldnt have to buy a bender and i could just screw the fittings together instead! i wouldnt even have to weld anything!

i had never thought of this -
thanks guys!

 

[Maximus]

I am in no way a fabricator but I have a little experience with both. Sch.40 pipe is great because it is cheap and you can even buy weld in 90's and so forth. Now I have only used some of this for racks and bumpers and sliders and stuff.

Companies such as Poison Spyder uses HREW in most of their buggy chassis so it can be strong enough if the design and execution is correct. Nowadays there are enough companies offering cages for you that would be designed probably better and are reasonably cost effective. Check T&J out of So. Cal if I remember have a full cage for about $1,000.

Good luck with whatever you decide.

 

[Ramsey]

and d and c extreme have one for 425. i'm gonna get it one day. of course this is advanced tech so a prefab cage doesnt quite belong

 

[5-90]

Could you build a cage out of plumbing pipe? Certainly. Would it be worth a damn? Iffy. Should you do it? No.

Pipe is not designed to serve as structural elements, it is designed to contain fluids or gasses at pressure. Pipe can be bent relatively easily (the only easier to bend metal tubing I can think of is EMT - which isn't even designed to hold pressure,) and any column strength it has is accidental.

Structural tubing can come in two flavours - REW (split into HREW and CREW) and DOM/Seamless.

"REW" means "Rolled and Electrically Welded" (H - Hot Rolled, C - Cold Rolled,) and this tubing will show a definite and pronounced "seam" where the edges were butted together and welded. While this can be used for light structural duty, it should be uses where static stresses will be encountered, and the tubing seams carefully placed to avoid rupture under load. If REW tubing fails, it's at the seam - nine times out of ten.

DOM - "Drawn Over Mandrel" is made from a solid, usually round, shape, that is heated and pulled over a shaped and pointed mandrel. The mandrel is sized to provide the ID of the tubing, and it is located within a drawing die. The amount of material used and the size difference between the mandrel and the drawing die determine the wall thickness and strength.

DOM tubing carries the advantage of being seamless, which simplifies fabrication by allowing you to orient the tubing in any direction (since you don't have to watch out for the seam.) DOM can therefore be loaded in nearly any direction that you would normally load tubing, and you don't have to worry about popping the seal - like you would with HREW/CREW.

DOM is also typically made from 4130 Chromium-Molybdenum alloy steel (or something similar - 4140 and other 41xx and 43xx alloys,) which is an alloy blended for weldability and minimal loss of strength in the Heat Affected Zone (HAZ.) Most ferrous alloys experience a severe loss of strength and embrittlement in the HAZ - which is how the various Cr-Mo alloys came to be.

It is still suggested that electrically welded Cr-Mo alloys are heat-treated after welding to reduce hydrogen embrittlement and loss of hardness/strength in the HAZ, but this can also be overcome by gas welding, rather than electrically welding. Gas welding should be done with a "carburising," or slightly acetylene-rich, flame, which works to prevent oxidising of the base metal, and works in much the same manner as welding flux.

I know I've gone into a lot of detail here, but it's important to remember 1*, and when it's yours on the line, you should do everything you can to tilt the odds in your favour. If you can't do it right, save your nickels until you can - it's cheaper in the long run, since you won't place confidence in something that doesn't deserve it.

I'm not trying to be an a$$ like the guys at PoR (I enjoy BillAVista's tech goodies, but I don't get into discussions much there...) but if I'm going to go into detail on something like this, I want you to understand why I'm saying what I'm saying. Blame it on middle and high school - the most common question on examinations was "Explain your answer" - which you were expected to do whether you were right or wrong. Frankly, I don't want to see anything happen to you that can be easily avoided...

5-90

(1* - One A$$ To Risk - especially when it's yours.)

 

[BrettM]

Could you build a cage out of plumbing pipe? Certainly. Would it be worth a damn? Iffy. Should you do it? No.

Pipe is not designed to serve as structural elements, it is designed to contain fluids or gasses at pressure. Pipe can be bent relatively easily (the only easier to bend metal tubing I can think of is EMT - which isn't even designed to hold pressure,) and any column strength it has is accidental.

Structural tubing can come in two flavours - REW (split into HREW and CREW) and DOM/Seamless.

"REW" means "Rolled and Electrically Welded" (H - Hot Rolled, C - Cold Rolled,) and this tubing will show a definite and pronounced "seam" where the edges were butted together and welded. While this can be used for light structural duty, it should be uses where static stresses will be encountered, and the tubing seams carefully placed to avoid rupture under load. If REW tubing fails, it's at the seam - nine times out of ten.

DOM - "Drawn Over Mandrel" is made from a solid, usually round, shape, that is heated and pulled over a shaped and pointed mandrel. The mandrel is sized to provide the ID of the tubing, and it is located within a drawing die. The amount of material used and the size difference between the mandrel and the drawing die determine the wall thickness and strength.

DOM tubing carries the advantage of being seamless, which simplifies fabrication by allowing you to orient the tubing in any direction (since you don't have to watch out for the seam.) DOM can therefore be loaded in nearly any direction that you would normally load tubing, and you don't have to worry about popping the seal - like you would with HREW/CREW.

DOM is also typically made from 4130 Chromium-Molybdenum alloy steel (or something similar - 4140 and other 41xx and 43xx alloys,) which is an alloy blended for weldability and minimal loss of strength in the Heat Affected Zone (HAZ.) Most ferrous alloys experience a severe loss of strength and embrittlement in the HAZ - which is how the various Cr-Mo alloys came to be.

It is still suggested that electrically welded Cr-Mo alloys are heat-treated after welding to reduce hydrogen embrittlement and loss of hardness/strength in the HAZ, but this can also be overcome by gas welding, rather than electrically welding. Gas welding should be done with a "carburising," or slightly acetylene-rich, flame, which works to prevent oxidising of the base metal, and works in much the same manner as welding flux.

I know I've gone into a lot of detail here, but it's important to remember 1*, and when it's yours on the line, you should do everything you can to tilt the odds in your favour. If you can't do it right, save your nickels until you can - it's cheaper in the long run, since you won't place confidence in something that doesn't deserve it.

I'm not trying to be an a$$ like the guys at PoR (I enjoy BillAVista's tech goodies, but I don't get into discussions much there...) but if I'm going to go into detail on something like this, I want you to understand why I'm saying what I'm saying. Blame it on middle and high school - the most common question on examinations was "Explain your answer" - which you were expected to do whether you were right or wrong. Frankly, I don't want to see anything happen to you that can be easily avoided...

5-90

(1* - One A$$ To Risk - especially when it's yours.)

That's some good info there 5-90, a few issues I have with it though;

first, pipe is used in some scenarios for structural members, not just containing gas and liquid. there were several engineers on POR that showed large structures they've had a part in building which used "pipe" for structural purposes. I think your analysis is a good rule of thumb, because you must get the right grade of pipe for structural purposes.

second, DOM is rarely seamless. it is formed just like REW tube then drawn over a mandrel to provide for consistent ID and normalize the grain structure.

 

[5-90]

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'd not heard of pipe used as a structural member, but I don't work with a lot of pipe (I REALLY hate plumbing!) I don't doubt that it's possible, but it's not something I'd advocate generally - and it would take more engineering know-how than I have at the moment to design a reliable structure out of Sch.40 or Sch.80 - so I'm not going to recommend it, since I can't offer useful advice (and I'm not there to inspect anyhow.)

Another factor that works against pipe is that pipe threads - internal and external - are nearly always cut into the metal, rather than rolled. This created enourmous interruptions in the flow of stress all around the threads, and makes for serious weakness at the joins - conventional fastener threads are rolled after heat treat, which essentially makes it a "forging" process - yielding a stronger thread. The fact that material is not removed during rolling is a plus - the roots of the threads become harder than the crests due to the compaction of the material, and that helps to compensate for the reduced strength at the thread root (a combination of deformation, reduced diameter, and the semi-sharp "line" at the thread root all contribute to this weakness.)

If you can find someone with a proven record of designing high-stress structures from plumbing pipe, go ahead. Otherwise, I think you're better off taking it easy and waiting to do it right...

5-90

 

[Highlander]

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.....

 

[Roll-over]

... So the concensus is that "pipe" is fine for bumpers, sliders, and fender hoops. But NEVER use it for the exo cage that in many designs attaches to the bumper, sliders, and fender hoops? So here's an ironic question... When did HF start selling logic and what kind of return policy did you get?