The filament I wanted was out of stock, unless I bought a "refill" rather than a spool.
So I bought the refill, and made my own reusable spool.

The two halves screw together (with the refill sandwiched between them).

PLA probably isn't the best choice, due to brittleness, but as I get "free" PLA filament of
random colour from 3DQF, I used that ;-)

(https://www.3dqf.co.uk/product-page/re-worked-pla1-75mm-uk-made-3d-printer-filament)
