Check out this great build that was recently shared as a review on the T Connector

"I used the Makerpipe fittings to build a Rack for my pickup truck that would fit over my Softopper. It was a handy option because I could build it without buying a welder, or the clamps needed to weld such a configuration. The fittings are convenient to work with. I would forget about using a pipe cutter: Too slow. Just throw a good medium metal blade in your scroll saw. Another advantage over welding is that I can reconfigure the design if I find it needs to be modified in any way. I also built it "in place" over the Softopper, which I allowed for proof of concept/ better fitment. With welding, I would not have been able to do that because I would burn the canvas topper, obviously. If I really get serious about permanence or structural strength, I really could have my bass player weld the fittings, but they are very strong as is. I can haul my 135lb 1436 Jon Boat on the top of my Ranger with great confidence. The convenience is worth the price in my opinion."