5 ways to ruin your filament (and how to fix it)!

It’s super easy to ruin a perfectly good spool of filament. Learn what to avoid if you want to keep your 3D printer’s filament in perfect shape!

Avoid: Tangling, high temperature, pets, bad filament guidance and cooked filament!

What’s up everyone, Tom here, and have you ever ruined a perfectly good spool of filament? It’s easier than you think, and while some of the things I’m about to show you can mess up a spool for good, some can easily be fixed. So let’s check out my most common mistakes you can make when handling 3D printer filament and how you can fix them.

Number one: Tangling your filament!

It’s so easy to do – you unload it from your printer, set it down for a second and there you go: A spool that looks perfectly fine on first glance, but is going to choke on itself half an hour into a print. What happened here is that the end of the filament slipped under another coil, which doesn’t sound too bad, but because that has messed up the order of the windings, when you use it normally and have the printer unwind it, the end now gets caught and stops the print dead in its tracks.

But thankfully, that’s super easy to avoid! Remember, there are only three valid positions for the end of a filament spool: Loaded and ready to go in a printer, in your hand after you took it out or secured to the spool with the holes on the edge or securely taped to it. Under no circumstances should you let go of the end of the spool and let it dangle around. Storing it without the end clipped in is an absolute guarantee for disaster.

But let’s say you’re already past that and have a spool that you just need to babysit and keep from tangling. Well, there’s an easy fix for that: You’ll need to properly rewind the part of the spool that has the filament crossed over. But instead of unwinding it normally, which would just shove that part further onto the spool, you just have to unload a couple windings off the side of the spool. To do that, hold the end of the filament and rotate the spool to loosen up around 20 windings or so, depending on how messy your spool is. Then pick it up and carefully work the filament over the side, several windings at a time. This will also push whatever knot you might have building on the spool up over the edge and give you a nice, clean surface to start rewinding the filament. Keep it nice and tight and you should end up with a perfectly reliable and usable spool again. And please make sure it stays that way by not letting the filament end dangle around.

Number two, climate control.

There are two things that can degrade your filament’s printability: Moisture and heat. Let’s start with moisture: Different filament types are more or less sensitive to moisture. Some Nylons can go bad in less than a day if you leave them out in the open, but there are blends that are less sensitive. PETG and other copolyesters as well as ABS also have issues with moisture absorption, it’s not quite as drastic, but both with produce weaker and less crisp prints than fresh and dry materials. PLA, on the other hand, does also absorb ambient moisture, but usually doesn’t degrade as noticeably as the other materials. Common moisture indicators are popping sounds while printing, visibly bubbly surfaces, extra stringing or even nondescript issues like extruder hiccups or clogged nozzles.

I’ve previously shown how to build a drybox like this that you can use to store filament and directly print out of, but usually, even just using using any sort of plastic bag, maybe with a bag desiccant in it, the one that came with the filament is great for this, that is already good enough to store filament while not using it. rigid.ink include a separate reusable bags with every spool, and with some manufacturers you can use the original packaging if it has that zipper part in it.

Otherwise, just grab some larger ziploc-style bags and use those for filament storage.

It can sometimes still be necessary to actively dry out filament before use, and the easiest way to do that would be to pop it in the oven and letting it bake for a while. However, this is where that second part of climate comes in. Generally, it’s a good idea to keep the temperature well below 50°C, that is about 120°F. Many filaments start to do some really awesome, but weird stuff once they get heated past that temperature. I did a video on the topic of heat-treating printed parts a while ago, and I’ve often experienced the same thing with random printed parts as well, where the material properties drastically change once they were heated past a certain temperature for a while. Generally, what happens there is not great for raw filament, and if you’ve had a far-east filament spool just shattered into bits as soon as you opened it, well, that one’s probably been sitting in a top-row shipping container in the sun for a while.

So for drying, one or two hours in the oven is fine, but if you leave your filament in your car on hot summer day, chances are, you’re not going to enjoy printing with it the next time.

Number 3: Keep your filament away from toddlers. Or cats or dogs.

I can tell you, a filament spool can be quite interesting to the little critters, if you’ve ever seen a cat unroll an entire roll of toilet paper or your dog chewing up your shoes, well, a spool if filament is just as interesting. So, just keep your stash out of reach or behind closed doors and avoid turning them into entertaining, but costly chewing toys.

Number four, your spool holder on your 3D printer itself can cause some pretty nasty issues.

Of course, it’s bad when there’s too much friction and the spool can’t freely rotate, but it’s also not the best thing if your holder is too smooth and just lets the spool spin freely. It can really easily pop off the side and tighten up there or become so loose that you’ll get a knot similar to what happens when you let go of the filament end. Just this one will fix itself if you babysit it long enough.

To add a bit of friction, it can often be enough to just add a ziptie somewhere and leave the end to rub against the spool. Or you can add a small piece of cloth somewhere that does the same.

Another issue that commonly pops up with filament spools is that the filament path isn’t restrained well enough and will sometimes have your filament get pulled off sideways, which, again, will have it tie itself around the spool holder. So, easiest fix, again, a zip tie if you have to, but any sort of guidance right at the spool will keep this from happening. Some spool holders use a short piece of Teflon tube, but creative and use whatever makes you happy.

And number five, cooking and caking your filament.

While this one isn’t strictly related to filament spools per se, it’s still something that knowing about doesn’t hurt. Essentially, when you leave your filament in a heated hotend, it very slowly decomposes into nasty, unextrudable carbon flakes. This is grossly oversimplified, of course, but the hotter the hotend and the longer you leave filament in there, the more likely you’re going to run into issues on your next print.

So don’t leave your printer sitting around heated up for extended amounts of time.

The quickest way of turning off the heat is by just flipping the power switch. Well, wrong, because there is a serious issue with this, particularly with PLA. Because most modern hotends rely on a fan to keep their heatsink cool, and the PLA from sticking to the unheated part of the stainless steel heat break, suddenly taking away that cooling while the block is still hot can and will most likely get your PLA to stick to the wrong parts of the heat break. E3D v6 clones that don’t use a teflon tube extending into the heater block are extremely likely to do this, since the turned-down part of their heat break, which is what’s actually insulating the hot and cold zones, is usually thicker than the real deal, which means it’s transferring heat into the cold zone more easily.

So for me, the actual quickest way of shutting down a printer is by using the reset button – that turns off all heaters, but keeps the cooling fan on as long as necessary, and once the hotend has cooled down enough, then you can switch off the rest of the printer.

So, let’s recap what we learned:

1) The end of a filament spool should either be in a printer, in your hand or clipped to the side of the spool. 2) Keep your filament cool and dry. Duh. 3) Pets like cats, dogs and small children love to play with filament. Don’t let them. 4) Your spool holder needs the right amount of friction and some filament guidance. And, 5) Well-done is not ok. Don’t overcook your filament in your 3D printer.

And that should keep all your filament nice, happy, cozy and ready to go. If you have any tips of your own, drop a comment below or share them in the community forums!

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