Re: Mast \"A\" frame construction ....
Without the tech spec for the modulus of elasticity, yield strength, and a few other bits of info, it would be difficult to perform a finite stress analysis of the A frame and the pipework. I guess you could show to yourself how relatively weak a 2mm wall on a 22mm dia pipe is by placing the ends on two chairs and sitting in the middle. It's guaranteed to buckle.
Why not use a couple of old ally spinnaker poles ? They are designed for tension and compression, and the shape resists bending.
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