Filament spools start to pile up and you need somewhere to store them efficiently. This is one solution to the problem because it puts the spools on a shelf where they are easily accessible while also being up and out of the way.

This shelf uses the brackets and PVC pipe to keep the spools from hitting the wall but not out too far. When choosing a shelf size keep in mind that spools are not light. You will need three or more brackets for lengths greater than 32in.

When mounting the brackets I strongly recommend putting the screws in studs, this also makes it so that the brackets are some multiple of 16in apart. 32in worked well for me but if you want a different length simply get a different length of PVC pipe. My pipe was technically 36in this provides a little extra so you don't have to worry about it sliding out. Factor in this extra when figuring out how much pipe you need.

The PVC pipe I used was not standard. I used ¾in schedule 40 pipe. I used 1/8in screws with 1/4in washers to hold the brackets in place. The screws are 1/8in diameter and must be at least 1.5in long. Washers are 1/4in inner by 1/2in outer diameter. Link to materials below.