We've all been there - you get a loose coil of filament included with a new printer, or maybe from a trade show.

You try printing with it, but it quickly becomes a tangled, unusable mess.

Not anymore! 

I modeled this two-part spool holder to closely match the dimensions of some sample coils I had laying around. You should be able to cut any zip ties keeping the filament together, then carefully slide the coil around the inner diameter. Set the other half of the spool in place, and rotate to tighten.