Making my own armor? What wall thickness for DOM bumpers and cages? I figure diameter is a little more personal preference? I suppose I'd mach it to my sliders if I ever receive them.
DOM for bumpers is a waste, save your money and go with HREW, it is just as good. If you are concerned with the seem being a weak point, just point the seam away from impact points, and reinforce those high impact points/areas with gussets or bracing. Internal or external cages are another issue, DOM is stronger and no seam to worry about, which is why organized motorsports associations require its use, however a poor design or weld makes DOM good design and welding is as important to structural integrity as is the material used.
Good right up on a comparison between the two herehttp://4xi.biz/4xi/DOM.V.HREW/HREW_vs_DOM_tube_test.pdf
Video link of how they tested each,https://www.youtube.com/watch?v=sdQPhzA44ms
Outside of a winch plate and mounting brackets, 1/8"(0.125) is plenty strong for most uses in the off-road environment. Sure it doesn't sound/feel as strong when you hit it with something, and it takes a little more engineering than 1/4"(.250), but with 1/4" weighing 1-2lbs more per foot 1/8", 1/8" will not only save you money on fab costs, but fuel mileage as well.