This is for the Hovercraft I'm building (in the "Personal Projects" forum)

The plans called for 1/8" aluminium tubing to reinforce the prop mount platform. I wanted something a little more substantial to make sure the prop did pass (or pass through) me.

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I used 1 1/2" by 3/16" angle and 1/2" conduit. It was still pretty lightweight and seems strong than small aluminum tubing. It still needs bolted into place.

No close-ups of the welds on this one. It was tough to weld the conduit without getting burn through. It did burn through in two places, but I was able to build up the bead to close it off.