I love in Colorado, which is a pretty dry state, so while I had heard of “wet filament”, I never considered it to be a problem that I would have to worry about. I had seen people creating dry storage bins for their filament, but figured that must just be for people in humid climates.
When I first bought my 3D printer a few years ago, I did what most people probably do - I bought a 10 pack of different filament colors. Everything printed great for a while, but eventually, my prints just started to kind of suck. I made a few upgrades to my printer, but still couldn’t pinpoint what was going on. What was frustrating, is that some times my prints would be great - but other times I couldn’t even print the most simple prints without problems.
I eventually noticed that my great prints were from newer filament that I had recently purchased, but my bad prints were coming from spools I’ve had sitting out for a while. So I purchased a $40 filament dryer on Amazon and it instantly fixed all the problems I’d been having.
I feel dumb, because I had gone through three different extruders, new hot ends, new nozzles, tubing, and spent tons of time cleaning and tightening stuff on my printer. I had left my printer untouched for months because it was just so frustrating. Something as simple as old filament left out never occurred to me until much later.
TLDR; If your prints have started to suck after a while, you might want to try drying your filament.
Dry and then store in a controlled environment. I’m using those bog standard cereal containers from Amazon (3,7-4l container should do for 1kg spools). Add some desiccant, spool rollers and a hygrometer and you have yourself a semi-permanent home for your spools. Mine show somewhere between 10% and 15% humidity, so that’s pretty good considering that previously just leaving a spool in open air for a single longer print caused it to soak enough moisture to ooze and string by the end of the print, and that’s in “only” over 40% humidity. So yeah, highly recommended.
Quick addendum: Cheap digital hygrometers from Amazon can be off by as much as 10% or more and are kinda pointless, poorly designed and a waste of batteries.
Simply using some color changing desiccant will save you a few bucks. (It’s something I use here in Colorado for my jars of… “entertainment products”… that is legal here, in addition to my filaments.)
There is desiccant available that is formulated to hold specific humidity levels but filament is better served by pure silica gel.
One thing to be aware of is if your filament gets too humid and you dry it out it won’t perform the same as when it was fresh. It will perform better, but not like new. In addition to drying mine out I make sure to store it in a sealed container filled with desiccants. I just take them from various packages and throw them in there. I bought a huge tub from Menards a white back that has a rubber or foam gasket to help keep the humidity out. Just a regular lid only helps so much. The tub wasn’t expensive and I have like 10-15 1kg rolls in there.
I live in high humidity, so that’s a big part of my setup. I print from a custom dryer with 4 spools in it, which feed to the printer through PTFE bowden tubes. I have a wifi switch for the dryer that just turns on once in a while to keep the ones sitting there from getting wet by keeping the inside of the dryer, well, dry. I store all my filament in containers with a 3d printed silica containers that go into the spool. I use the “rechargeable” silica beads that change color when saturated. Once in a while, when I see that the beads are turning blue in the containers from opening and closing, I will do a drying session where I dry all the silica containers and the spools for a good while and put them all back into the containers. Can be a bit overkill, but it fully eliminates that factor for me!
I’m thinking about getting some of those activated alumina beads. I’ve heard they are both more efficient at absorbing moisture and can be recycled indefinitely without degrading. Sounds like a perfect fit for your setup.
Just had to look it up, never heard of it! Thanks for the suggestion.
I couldn’t agree more. I recently had the same thing happen to me. I ended up getting a dehydrator from a thrift store and converting it to my needs. It really does make a big difference, but I don’t think there’s any reason to feel silly. Now we can pay back and help the next guy or gal that comes along with the same problem. :)
I had the same realization. I spent 3-4 hours fiddling with different settings, with no impact, and then 1 hour drying did the trick!!
Lol I’d say you’re lucky that it was only 3-4 hours!
So I’ve toyed with buying a dryer, but I never really understood a good workflow. Do you dry a spool right before you start printing with it?
What about storing spools? Is it sensible to leave them in “regular” storage before going into the dryer? Or should I be looking at having multiple dryers to keep more spools from getting wet. And at that point should I just be looking to make a more practical storage solution for many spools?
I store in home Depot containers with desiccant in the bottom. And have another modified to print from. (Printed spool holder with bearings, reverse Bowden through container side)
It really didn’t change my workflow, just where to get the spools to load, and where to load them.
Print quality improved greatly.
Most dryers now allow you to print directly from the dryer. I keep my spools like most in cereal boxes with a 100g dessicant sack. For pla I just throw it in dryer, set a timer on it, while I’m prepping my bed and print. Works well. For PETG or tpu I like to try to let it dry in the box for a couple hours before getting started. If you are not carefully keeping filament dry and switch to a sealed dessicant system, I would recommend putting the filament in a drying box for 8h prior to then putting it in your storage container. I tried vacuum bags for awhile and the cereal box thing is way less of a pain.
I still don’t understand how those cheap filament dryers work: they fully enclose the spool and heat up the air for a few hours. But where does the moist air go? It’s still trapped in there with the filament. It makes no sense!
I always leave the filament dryer a bit open so the warm air can escape, taking the moisture to a better place (far away from the filament)
Humidity is relative, not absolute. Air’s carrying capacity for water increases as temperature goes up, even if the total amount of water in the air is the same.
Air with 50%RH at 70F (eg, it has 50% of its max water content) only has about 10%RH at 120F. So if you get the filament hot, it gets dry. This can be improved with outside air circulation i guess, but it’s not necessary and usually causes extra energy use due to heating the makeup air.
That I am aware of. But without any circulation the hot air will simply cool down and condensate once I turn off the dryer, wouldn’t it? Leaving either highly saturated air or even some water droplets, ready to be absorbed by the filament again
This is true. If you left it in the same environment it would eventually return to equilibrium and the net result would be the same. the key is that the plastic has a limited take up rate of atmospheric moisture. so if you dry it for a few hours, the water migrates out slowly, but then takes quite some time to migrate back in.
generally people either print from a dryer box or dry filaments immediately before printing.
You’re supposed to put some type of desiccant like silica gel beads that will pull that moisture out of the air.
Leaving the box open will just let humid air in. You can’t let air out without also letting air in unless you have some sort of vacuum pump.
Now that you mention it, I have no clue! There’s no exhaust fan on mine. It definitely works though, so I assume the people that made it are smarter than me.
I had the same problem but it can get so humid here that I’m drying my filament every day.
