I was looking for a filament rack and the ones I found used tubing which wasn't that easy to get hold of in the UK. I wanted it to be extendable so you could expand it as you got more filament.
I modelled one from scratch in Fusion360 (to give myself some experience) to fit standard UK 22mm copper pipe.
You could use 22mm PVC pipe, but you'd need to use the Schedule 40 spec to prevent it bending.
I printed in several generic PLA at 0.3mm layer height with 10% infill. Gives a really strong piece.
Two pieces took around 8hours on Artillery X1 sidewinder.
I added supports touching build plate only which creates a very easy to remove plug for the lower 2 holes. The horizontal holes print fine without infill.
Copper pipes were cut at 25mm for the vertical and 60mm (my bench size) for the horizontal. A generic pipe cutter is fine and the ones which spin round the pipe are so simple to use and very little effort.
I've added the .dxf so you can further modify it yourself. If you want any mods, or files in a different format just ask.