Various forms of metal tubing are widely used in fences, plumbing, and in electrical distribution systems. I have built a number of dome frames from 3/4” electrical conduit cut to specific lengths and ed 1/4” bolts to connect them through holes in the flattened ends.

   For larger structures I have used thicker conduit or top rail secured with 5/16” or 3/8” bolts. These versatile structures can provide strength and portability at a cost that is hard to match in any other format.

   Sheet metal screws installed in selected pieces can secure tarps or plastic in an overlapping manner that can shed rain as shown here.

   One useful format is that of the geodesic dome invented by Buckminster fuller. You will find a simple but very versatile form of this in 16' Bolt-together Dome.

   Another frame material that I intend to try in the near future (but have not yet), is welded pieces of reinforcing steel. The intent here is to create small permanent low-profile dome shapes.

In the section on parabolic domes there are structures of higher complexity, in addition to instructions on how to calculate them. From these you can select section that would give you the depth of profile optimum for your application.

   They would work for roof frames for small backyard structures, be or delivered to homeless camps where they could support materials for shade or weather protection. Their low-profile would make them easy to conceal, and suitable for covering small hollows. If a person had country property they could take larger structures out in welded sections, and join them in place for a seasonal camp site.