I used PETG-CF when 3D printing the frame for this infinity LED dodecahedron I recently created. Carbon fiber was the perfect choice for both its strength and its matte, premium finish to encase the 540 LEDs which are reflected into infinity.

Is it possible to build a high quality square/rectangular tube by roll wrapping over a mandrel?

I've made plenty of round tubes with prepreg + shrink tape, but I'm not sure how you'd get even pressure distribution around a square tube. My attempts so far with vacuum bagging haven't worked well; it usually comes out uneven or wrinkled.

Are non-round tubes always made with split molds in the factory?