Pipe Stand Engineering Question

**scroungetech** · 10-22-2013, 19:03

Greetings All,
As the weather gets colder here in the Northeast, I'm on the verge of putting together a steel pipe hammock stand for indoor use, made from 1 inch diameter galvanized steel pipe. I have a question for those of you who use this type of hammock stand.

Have you had any successes or problems with splitting the long pieces of pipe into smaller sections and using more union fittings to join them together? Specifically, the pipe stand showcased at

http://theultimatehang.com/2012/07/p...ck-pipe-stand/

calls for 4 sections of pipe, each 6 feet long. I'm thinking of splitting these all into 3 foot sections for better portability, so each upright part would be comprised of two sections of 3 feet each, and the horizontal pipe would be made of four sections of 3 feet each. Or maybe three sections of 4 feet each. Just so it can all fit in the trunk of my sedan. I could make it on spec per the drawing at the link above, it will just be a hassle to transport, if I do ever want to transport it.

Has anyone tried this? Do you think it will affect the sway/sag factor? I weigh about 250 pounds and am using a DIY double layer from a template at DIYGearSupply with a structural ridge line of about 11 feet in length.

Any feedback or related experiences are appreciated. Thanks!
~scroungetech

**Bannerstone** · 10-22-2013, 19:57

Gotta have a good reason to go with steel considering the weight penalty. You can get better rigidity for less weight with aluminum.

David

**oldgringo** · 10-22-2013, 20:15

It will work, as long as you use pipe wrenches and get your joints tight. This will drive up cost and weight...more cuts, more threading, more fittings. As long as you don't mind that, and the additional time requirement, go for it.

**Rest Step** · 10-22-2013, 20:23

Unions aren't designed to be structural splice fittings for pipe, they are designed for holding specific pressures within the pipe. I'm not aware that there is any engineering data for the structural strength of unions. In the stand diagram, the union at the top pipe member would be in pure compression and this is safe. If you start to use them where there are bending moments and shear stresses, you are taking a risk. I wouldn't do it.

**lmoseley7** · 10-22-2013, 21:55

Pipe is thinner at the threads. I've seen pipe break off at the joint before. Maybe consider two sizes of pipe, one that nests inside the other with some overlap. Or reinforce the joints with a dowel to prevent bending at the joints.

**Dave-O** · 10-23-2013, 12:09

I made a steel pipe stand that uses 3 sections of pipe for the horizontal bar. The pipes are 1.5 meters each (I lived in Germany when I bought the pipe) and use two union joints. The pipe is 1" in diameter. It works ok, but the horizontal section isn't what I would call straight. It works well to test gear, but I've never used it overnight.

Hope that helps.

Sincerely,
Dave-O

**nothermark** · 10-23-2013, 15:33

Also note that the Jacks used 2" pipe. If I was going this route I go larger than 1". I would also use regular screw in connectors on the legs and wrench tighten them. You will also want to cap the ends of the feet or they will rock on the center T. They may anyway.

**Darby** · 10-23-2013, 16:08

Originally Posted by nothermark

Also note that the Jacks used 2" pipe. If I was going this route I go larger than 1". I would also use regular screw in connectors on the legs and wrench tighten them. You will also want to cap the ends of the feet or they will rock on the center T. They may anyway.

They will rock without caps. I actually have Ed Speers stands (2") and some I made myself (2") which we use at events where the public is going to get in & out of the hammocks all day long. As Rest Step stated, unions are designed for interior pressure, not structural stability. They work fine on the top bar, I even added a 30" section in the middle (2 unions) for prototype work with no problems until I hung something too heavy from the top bar and split a union nut. I would not try this on the uprights. Also keep in mind that you will have to carry two pipe wrenches. I never use them to assemble (except the union) because you can tighten it plenty by hand during assembly, but tearing down you will need them.

**Darby** · 10-23-2013, 16:20

After re re reading my last post, I realized I didn't make this clear

.
My base is pre-assembled with the Tee, the uprights are bare threaded on both ends and the top bars have the 90's on one end and half of a union on the other. I assemble from the base up on both sides, then join at the union last.

**oldgringo** · 10-23-2013, 16:45

A union is a 3 piece fitting that is heavy, pricey, bulky, and not very rigid. Only one is needed for the top bar. All other connections can be made with couplings, which are 1 piece, rigid, and relatively inexpensive. I would trust 2 piece uprights assembled with couplings but would not use 1" pipe. I built one three years ago, and use it inside a canvas tent during deer season. The design is functional, and has the advantage of a small footprint. It is, however, heavy, bulky, and expensive. Not my first choice.