Keep 3D Filament Dry and Improve Print Quality

by Oscar

It’s important to keep your 3D filament dry. Filament with moisture trapped in it can cause quality issues with your prints. I will show you how I store my 3D filaments in low humidity condition.

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Moisture in 3D Filament Ruins 3D Printing

Moisture in filament is really, really bad for 3D printing. Quality not only goes down the drain, printing also becomes so much harder no matter how you adjust your settings.

When I first started 3D printing, whenever new 3D filament arrived, I would just take it out of the box and start printing right away. Printing quality wasn’t always good and I would blame the quality of the filament. Maybe that was it, but one important thing I overlooked was the moisture in the filament.

3D filament we buy online could have sat in a warehouse for who knows how many years, and possibly in a humid environment too.

It didn’t come across my mind until I started storing all my 3D filaments in a storage box with desiccant. I printed something with the same TPU filament I used last year, which gave me terrible result the last time. Only this time, the print came out beautifully! I swear I didn’t touch any settings, but the quality difference is HUGE!!

I was so ready to bin that spool of filament, but now I know it just needed to be dried.

Drying filament before printing clearly makes a big difference to printing quality, this applies across nearly all types filaments for me, TPU, ABS, PLA… As you can see in this example with TPU, the model on the left that was printed out of dried filament has a much cleaner, shinier and smoother finish.

You can even hear the sounds of bubble bursting as the filament is coming out of the hot end if the filament contains too much water, it’s kind of hilarious.

How to Remove Moisture in Filament?

The simplest and most common way to dry 3D filaments is putting them in the oven with low heat. I don’t really feel comfortable mixing plastic with my food stuff, so I decided to dry my filament the slow way – desiccant in a storage box.

It can take days to remove most of the moisture, but it will keep it dried all the time after that.

How to Store 3D Filament?

Here is how I do it. First, the shopping list:

Get a storage box that is big enough for all of your filament spools. Mine is 20 litres, 480 x 310 x 205mm. Don’t be afraid to get a big one as long as you have the space.

Try to get one that is airtight. If not you can always just get some “foam seal strip” to make it as airtight as possible like I did here, US Amazon:; UK Amazon:

For desiccant, I went with rechargeable silica gel, which can be “reactivated” by heating them up when it loses effectiveness. I bought a tub of 500g, and I only had to recharge every 3 to 5 months.

You can just leave it loosely at the bottom of the box.

I put the silica gel in this 3D printed box ( so they don’t get all over the floor when you take the filament spools out of the storage box. It’s good for 2mm or larger beads. It also makes it tidier as well when you have to take them out for recharge.

Use a digital hygrometer to measure humidity inside the storage box, the cheapest ones would do. With the presence of the silica gel, humidity is normally around 15% to 25%.

Hope that was useful! Happy 3D printing!

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Aaron L Richards 4th November 2019 - 4:50 pm

I baked a spool of TPU at 170degF for 6+ hours. 170 is the lowest my oven would go. Might have over-baked as I now can not print successfully with the baked spool. I have successfully printed with TPU in the past, including with the spool that I recently baked. I do not know if baking at 170degF for 6+ hours changed the geometry of the filament, or something else is wrong. Unfortunately I looks like half a spool is wasted.

Steve 15th March 2019 - 5:56 am

I also find it a good idea to put TPU in the oven for 40 mins at 70 Deg C before printing with it. It makes a massive difference to the print quality.

Relic 11th March 2019 - 7:54 am

I have Oscar’s setup – desiccant, plastic bin with homemade seal strip added – and find it exhausting to keep the dessicant fresh. The seal just isn’t good enough. I think proper vacuum bags are the only sustainable strategy at this point.

Markus 11th March 2019 - 2:59 am

I’d be curious to hear if you use supports at all for the gopro mounts. Your prints look quite clean where the lens would be and I’ve found that I dont get it nice clean like that because I’m using supports.

Are you orienting the print a certain way to not use supports?

Oscar 11th March 2019 - 4:57 pm

Yes, I did use supports on these prints.
I orient them in a way to minimize the need for support. On this gopro mounts, usually with the left or right side of the mount facing up.

Frostbyte 10th March 2019 - 2:09 pm

I use a vacuum chamber to dry saturated filament and then store it in a sealed box with dessicant. I have recovered totally ruined spools successfully.

Peter 10th March 2019 - 1:17 pm

I put the silica gel in stainless steel tee eggs. So you can throw the whole thing into the oven for reactivating without throwing the little beads everywhere.

Aaron J Peterson 10th March 2019 - 11:47 am

Desiccant is not effective at removing moisture from hydrolyzed filament – even after long periods of time. You have to cause the filament to out-gas the water it has absorbed, which requires heat.

Desiccant does a fine job of removing moisture from the air in an enclosure, keeping already dry filament dry. So transfer and store filament in the dry box to avoid having to heat it.

But if it’s too late for that, you’ll need heat. At the very low temperatures necessary, there will not be dangerous chemicals coming off the plastics so it is safe to use your oven. Just don’t bake at the same time! For convenience I use a cheap food dehydrator with the trays clipped out to fit the spools.

Oscar 11th March 2019 - 4:54 pm

Don’t know much about “hydrolyzed”… but it’s working pretty well for my filaments :)