Is schedule 40 pipe strong enough?

[TruckNutzDude]

I'm diving into the roll cage part of my project this spring and I need to know if this pipe will be strong enough. It's avalable in 1-3/4" diameter with a .185" wall thickness (I think) and it's about half the price of DOM and slightly less than HREW tubing. I have done some research on cage design and I plan on a lot of triangulation along with tying it into the body mount bushings. I believe I have heard of some people using schedule 40 pipe but I'm not sure about it. I doubt I'll ever roll my rig, but if I do I know the stock half cab will not be enough. I'm open to any kind of suggestions on how I can make this pipe work for a safe roll cage. Thanks guys! [img]/forums/images/graemlins/bow.gif[/img]

BTW If the post doesn't catch anyones attention I won't cry myself to sleep if it gets moved to another forum. [img]/forums/images/graemlins/waytogo.gif[/img]

[Sandman]

I think most people are going to say no. I guess it all depends on your piece of mind. I have people tell me that my HREW tubing was not a good choice and I've seen Schedule 80 pipe hold up fine to multiple rollovers. I would at least go with Schedule 80. That is what my side armor is made out of and it has held up pretty well.

[TruckNutzDude]

What is the difference between schedule 40 and schedule 80 pipe? I'm pretty sure the 40 pipe has .185 wall thickness, so does that mean the 80 pipe has a thicker wall? [img]/forums/images/graemlins/thinking.gif[/img]

[ntsqd]

First off, pipe is generally frowned upon for cage structure. The problem is that "pipe" is wide range of products. Could be anything from seamless steel pipe to cast iron pipe. My grandad builds a lot of stuff from he calls "Double Walled (Sched 80) Black Iron Pipe". Which isn't iron at all, it's steel. Wall thickness per Schedule changes with size. 12" Sched 40 pipe has a lot thicker wall than 2" Sched 40 pipe.

Generally only tubing is rated to carry structural loads. Pipe is rated for max operating pressure as some sort of conduit of water, steam, compressed air, oil, etc. While possible to extract an approximate structural strength from a pressure rating, it's not commonly done.

As a guideline the SCORE rule book calls for at least 1-3/4" x .120 wall steel tube in a cage structure for a vehicle the size of a K5. At some point in vehicle weight (8k lbs I think) they start requiring 2.0" x .120 wall.

If it is steel pipe and you can bend it wrinkle-free then it MAY be OK. Why not just get the stuff (tube) intended for the job?

[BadDog]

As usual, ntsqd's post has it pretty much all summed up.

I'll only add 2 points.

To clarify on the "anything from seamless steel pipe to cast iron pipe" point. Even if it is "steel", there are SO many grades and it's not really clear on most. Much of what you buy as "pipe" also lacks real specs on metal content. In particular, rumor has it that much of the "common" pipe you find is built in Russia from random scrap and is never consistent, often brittle and with inconsistent wall thickness (off-center ID).

And you said yourself that pipe is only "slightly less than HREW tubing", so why is there even a question? There is a reason that HREW is considered the "entry point" or "lowest acceptable" material for cages by most people "in the know". The only time you see people pushing "pipe" for cages, it's generally because it's "cheaper". And they maintain that it's good enough not on engineering principles, but based on anecdotal evidence or "opinion". They also generally wind up with heavier cages by going thicker/larger to recoup the loss of material strength.

I'm not saying in any way that you can't build a pipe cage to hold up. I'm not saying that those who use pipe are "idiots" or anything of the sort. But when HREW is close in price, I would not even consider pipe as an alternative…

[TruckNutzDude]

You guys have good points. In reality I was only looking at this as an option because of cost and avalability. The only close steel shop doesn't carry or can't get DOM or HREW tubing, just schedule 40 pipe [img]/forums/images/graemlins/doah.gif[/img] I believe the pipe was somewhere around $8 for 10 feet. Way cheaper than tubing IIRC. [img]/forums/images/graemlins/dunno.gif[/img] I haven't priced out tubing from any local places yet, just going by word of mouth. [img]/forums/images/graemlins/whistling.gif[/img]

[84_Chevy_K10]

Without even hitting the points above, pipe is simply too heavy.

[Thumper]

I think the biggest issue for me is this:

Have you ever picked up a 20' long piece of sched 40 pipe? Its freakin heavy. I cant imagine building a cage out of 100+' of it. Thats a pile of weight.
I dont know how the weight compares to HREW, I dunno what HREW even stands for, but I do know the piece of sched 40 pipe I have here is very heavy.

Mike

[dallassmith]

The way I have been taught is that pipe is for "POOP" pipe is ment to carry fluids,gases, it is not a structural metal.

HREW....hot rold electric welded you will notice that this tubing has a welded seam down the middle of it. Can be use as structural metal..ie roll cages

DOM....drawn over mandrel...no welded seam so its going to be stronger than HREW. does not have a place to split when you are bending a roll cage.

you can bend both pipe and tubing but they require different types of benders
tubing...JD2 type benders
pipe.... the orange pipe benders from harbor frieght

[img]/forums/images/graemlins/grin.gif[/img] [img]/forums/images/graemlins/thumb.gif[/img]

[BadDog]

DOM is just HREW with more work done. It still has a welded seam, you just can't see it very well.

And the JD2 style benders also have pipe dies available.