Loose coils can easily become tangled, but don't be discouraged. The key to a positive coil sample experience is control of the ends. Just like letting go of the loose end on a spool, letting go of the ends on a coil can quickly turn the loose coil into a messy knot.
Step 1 is to identify the head and the tail of the sample. For our subscription coils, we use a rubber band to retain and isolate both the head and tail ends. The head is on the outside of the coil while the tail comes from the inside of the coil and points in the opposite direction of the head (1).
Make sure to identify the head and tail ends correctly to pull the filament off the coil easily from the outside head, rather than pulling the filament from under itself. Feeding the tail end into the extruder first will not give a good experience!
Our subscription coils are designed to fit the core of the masterspool. There are many masterspool compliant designs available on Thingiverse from the original by Richard Horne to a 55g one for those preferring a lightweight option.
We've designed our own sample spool if you wish to check that out it's available at https://www.proto-pasta.com/blogs/how-to/a-new-sample-spool-for-your-filament-sample-coils
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Now let's demonstrate how to put the coil onto the masterspool without letting go of the ends. First, place the coil on the spool such that the tail can be secured (2).
We choose to tape the tail feeding it to the outside because the sharp 90 degree bends that normally holds the tail can easily break the filament leaving it unsecured. Once the tail is secure (3), we can move on to the head.
Take the rubberband off the head (4), but do not let go of the head.
Let the rubber-band fly off if need be, just don't let go of the head (5).
Now tuck the head into the retaining point built into the masterspool (6).
Twist the other side of the masterspool on and when the filament relaxes it's all nicely contained on the spool (7).
Happy printing! -Keith and the Proto-pasta Team
P.S. We're always open to improving the state of 3D Printing for a more positive experience. If you have prefer other coil sample spool designs that allow easy placement of the coils onto them without having to recoil and have spots to secure both the head and the tail, please share them with us by emailing firstname.lastname@example.org or tagging us @Proto_pasta on Twitter or Instagram.