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Step 2: Hub Preparation

Picture of Hub Preparation
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For the hubs I used schedule 80 PVC pipe, 3" diameter, cut to 1/4" less than the width of the struts. Perforated hanger strap, 22 gauge, would be held with two screws on each narrow side of the strut. The screws are stainless steel. The one farthest out is to hold the strap onto the strut and the one closer to the edge is to control pivoting. For the most part, these joints will take compression, rather than tension, so the straps maintain integrity but don't carry much load. Distortion forces should be transmitted through the structure as well, with all parts reinforcing each other. Nonetheless, each strut should be good for up to 320lbs hanging load individually, based on the ratings of the strapping and the pipe. This is important since I want to be able to hang things off of the inside of the frame.

3" sch 80 PVC is very cool stuff--solid, but expensive. Good thing I don't need much (~16'). I no longer have my load calculations, but it exceeded the ratings for the straps, so they won't be a failure point.

Each strap was precut and bent because it's too stiff to bend acutely without a tool and this made it easy to pop into place while constructing the dome.