Time has come to make some magnetic loop mounts.
My loop is made from 1/2 inch copper tube with a roughly five foot diameter. It will sit on a length of 1” PVC pipe. I designed some mounts in CAD, and 3D printed them with PETG filament. The top structure clamps onto the PVC, and holds the two ends of the copper loop. In addition to “friction fit”, I added a small clamp which will be tightened with an M2 screw and nut.
Short straps of copper are attached to each end of the tube. Later, these will be attached to the capacitor. This is shown on the right.
The lower structure is simply a rounded hook the fits over the the copper tube at the bottom. When this structure is clamped around the PVC, it will hold the loop in place, as shown upper center.
The completed assembly went together easily – see lower left picture.
Magnetic Loop Mounts – Is plastic rugged enough?
I can already tell that the top mount is not likely strong enough. When the copper loop ends are pushed into the holes, there is quite a bit of twisting motion from the copper tube causing pressure on the PETG part. I don’t think I put enough material around the holes to withstand the pressure. This is particularly so on the clamping side, where the number of plastic layers is quite low.
Also, the holes that take the copper tube ends (about 1”) are straight, while the copper tube is slightly arced. This adds to the strain.
I expect this to fail soon and will need a new design to make it stronger. This will include more material, more plastic infill for strength and making the holes slightly curved so the tube fits in better. I am happy with the choice of PETG filament, though. PETG is more flexible than my other materials, and this helps with the clamping arrangement.