Easy Guide to 3D Printer Filament Storage & Humidity – PLA, ABS & More

You’ve got your trusty 3D printer along with your favorite brand of filament, but for some reason you’re getting some poor quality prints, or your material is even popping for some reason. Chances are, you probably didn’t think about the humidity and moisture your filament is absorbing in the air.

Many people have been affected by poor filament storage and high humidity levels, which is why I wrote this article detailing some sweet storage tips and humidity advice.

The best way to store your filament when not in use, is to put it in an airtight container with desiccants to reduce moisture in the immediate environment. You can dry out your filament by putting it in the oven on a low setting for a few hours.

This article goes into some nice depth, with some sweet information that you should find helpful, so keep reading to up your 3D printer filament storage knowledge.

Does PLA & Other Filament Really Need to Be Kept Dry?

When it comes to keeping your filament dry you may have heard conflicting information about what you should be doing. This is the case because different environments and filament do require different strategies for storage and printing.

If we are talking about PLA, it is a plastic which does have some hygroscopic properties, which means has a tendency to absorb moisture in the immediate environment. However, it can only absorb so much water over time. 

One test found that PLA stored underwater for 30 days increased its weight by around 4%, which is quite significant when it comes to 3D printing but won’t make too much of a difference in normal conditions.

Unless you live in a very humid environment, combined with high temperatures, your PLA filament and even ABS filament should be just fine. These two filament are susceptible to moisture in the environment, but not to a point where it will have massive effects.

You can start to see negative effects in print quality and you might get a popping sound when moisture-filled filament is being heated to high temperatures.

PLA does tend to become brittle when it absorbs moisture, so you might see a weakness in your prints, or even see your filament snap while printing.

If you are experiencing this, there are ways to save your filament by drying it with methods which will be discussed in this article.

What you need to remember is how hygroscopic your filament is. 

Reasons you want to keep your filament dry:

  • Your filament lasts longer
  • Avoids your nozzle from getting jammed/clogged
  • Prevents print failures & low quality prints from moisture
  • Reduces the chances of your filament breaking and becoming weak/brittle

Which Filament Needs to be Kept Dry?

  • Nylon-based filament
  • PVA-based filament
  • Flexibles
  • Polycarbonate
  • PETG

Some filament requires plenty of care when handling and storing them. If you don’t have a room or area which is air-conditioned and has a controlled humidity, there are still ways around this with a few solutions.

The best way to keep it from going to waste is to store it dry and cool.

Ideally, any filament that you are using should be kept in a low-humidity, dry environment for the best quality. You should be treating all of your filament as if they are sensitive to moisture and store them properly.

Some people have definitely had some negative experiences with moisture-filled PLA filament, until they dried it in an oven for a couple of hours then it started printing great.

When your filament is out gassing steam, it’s just not going to print very well. Steam gets pressurized with the plastic and creates air bubbles which ‘explode’ or pop when that pressure is released, easily creating imperfections in your prints.

How to Dry PLA, ABS, PETG Filament & More

Make sure your filament doesn’t reach the glass transition temperature for any of these materials, or they will start to fuse together.

Also, ovens have quite wide margins of error on their temperature, especially at the lower ranges so I wouldn’t completely rely on your oven’s settings unless you have tested your oven temperature accuracy separately.

You probably don’t want this to happen to your spools of filament!

View post on imgur.com

I’d recommend using an oven thermometer before fully putting your filament in an oven to dry it, which is a common solution that you will hear about.

How to Dry PLA Filament

To dry PLA filament, most people simply put it in an oven for a couple of hours at a temperature of 120°F (50°C) and it comes out just fine.

Some oven settings don’t actually go as low as 60°C, so in this case you’ll need to either use a friend’s oven, or use a different method.

It’s a good idea to put some tin foil over the top of the spool to protect it from direct radiant heat. If you have an electric oven you need to shield your spools from direct heat exposure.

I’ve heard of people using a food dehydrator, which should fit a standard spool of filament.

Depending on what model of dehydrator you have, if you do have one, you might be able to make adjustments to it to fit a spool of filament. Heat does need to be applied to the filament to actually take the moisture of out it.

A simple dry box with desiccants may not work, as that is more of a method to prevent moisture from affecting your filament in the first place. It’s more of a way for long term storage.

Some people use uncooked rice as a cheap desiccant solution.

How to Dry ABS Filament

ABS works in a very similar fashion to PLA, but it just needs a little bit of a higher temperature. The temperature we use to get rid of moisture comes down to the glass transition temperature.

The higher the glass transition temperature, the higher heat you’ll need to implement to adequately take the moisture out of your filament. The common consensus is to put your ABS spool in the oven at 70°C for an hour or two.

How to Dry PETG Filament

PETG is a copolymer modified version of PET, which gives it a lower melting point so make sure you differentiate the two in terms of temperatures you are using.

A good temperature to use to oven-dry your PETG filament is around 150°F (65°C) for 4-6 hours.

You can actually make use of your printer’s heated bed and dry up filament by placing foil around it to retain the heat.

Set your bed’s temperature to around 150°F  (65°C) and lay your filament down for around 6 hours and it should do the trick.

How to Dry Nylon Filament

The video below shows the difference between 3D printing with wet Nylon vs dry Nylon.

A good oven temperature to dry your Nylon filament is around 160°F (70°C) but it does need a lot more time in the oven to fully dry. In some cases it can take even 10 hours to really remove all the moisture from Nylon filament.

Drying your filament shouldn’t emit any odor, so your house shouldn’t start smelling while you are doing this.

I would much rather start at a lower setting and work your way up if necessary so you don’t end up ruining a spool of filament.

Can You Dry Filament in the Sun?

If you are wondering whether you can dry PLA, ABS, PETG or Nylon filament in the sun, even when it’s hot ouside, you’ll be interested to know that the sun doesn’t get hot enough to evaporate any moisture that has been absorbed into your filament.

Your filament will also absorb moisture while sitting outside which is counterproductive to trying to dry your filament in the first place.

What Effect Does Moisture Have on 3D Printer Filament

As previously mentioned, moisture can lead to prints being unsuccessful or having print defects that just make your prints ugly. The moisture actually makes your filament weigh more because it retains that water within the plastic.

That same water, when put through high temperatures can lead to it popping. Although you might not notice a large change in your filament, moisture can still effect your print quality even when prints don’t fail.

If you are printing with Nylon or PVA-based filament, you are definitely going to want to take proper care and use preventative measures to stop your filament absorbing moisture.

Many composite materials like Wood-fill PLA are more likely to be hygroscopic than the regular type of filament.

If you’ve ever gone through a time when your print quality just kept on failing, then after you changed filament it got better again, this could have been down to moisture killing off your filament.

I’m sure there are many people who have thrown their spools of filament, just not knowing that there was an easy fix for their issues. Luckily, you have stumbled across this article which details this information so you can put it to use.

Moisture isn’t always going to be the reason, but we can definitely check it off a list of possible causes to narrow down our printing failures or low quality prints.

How to Store Your 3D Printer Filament Properly (Desiccators)

DIY Dry Storage Box

You can actually make a dry storage box/containers from standard parts which can be used to store filament or even as a spool holder where you can directly print from.

You’ll need:

  • A storage box (Amazon – has many sizes), make sure it fits your specific filament spool. Get the dimensions right and one that fits smoothly.
  • Sealing material – door or window gasket
  • Bag of silica gel or desiccant – to absorb moisture
  • Filament spool holder – 8mm smooth rod with 3D printed holders to keep filament suspended.
  • Tubing or pneumatic coupler with PTFE tube to guide your filament through
  • Other tools such a knife, scissors, drill & drill bits and a hot glue gun

Professional Dry Storage Box

PolyMaker PolyBox Edition II (Amazon)

This professional dry storage box can easily print with two 1KG spools of filament at the same time, making it perfect for dual extrusion 3D printers, but still working well with single extruder printers. If you choose to use 3KG spools, it can fit that without issues.

It has a built-in Thermo-Hygrometer allowing you to monitor the humidity and temperature within the PolyBox. You can keep a humidity level below 15% with ease, which is the recommended level to prevent your filament absorbing moisture.

You can use both 1.75mm filament and 3mm filament.

There are areas where you can place your reusable desiccant bags or beads for that fast drying action. The bearings and steel rod makes your filament pathing nice and smooth throughout the printing process.

Some people had issues getting the humidity down below a certain percentage when placing two filament spools in the PolyBox, so they added another product.

The Eva Dry Wireless Mini Dehumidifier (Amazon) is a nice, inexpensive addition to your filament storage strategy. It lasts a sweet 20-30 days before it needs recharging, and is a simple ‘hang & go’ style product.

It has multiple uses for your storage box, your cupboard, dresser and many other places, so I would definitely recommend getting one or a few for yourself. It doesn’t require any electricity or batteries either!

You can also get yourself some Dry & Dry Premium Silica Beads from Amazon which are rechargeable. They have 30+ years of industry experience and are happy to offer a 100% refund or new replacement guarantee if you aren’t happy with anything.

If you are after an inexpensive temperature and humidity meter, I’d recommend getting the Veanic 4-Pack Mini Digital Temperature & Humidity Meter.

It’s a useful gauge to have if you don’t already have some type of device which measures humidity. They are called hygrometers and are usually built-in to those professional filament storage boxes.

Best Vacuum Sealed Storage Bag

A vacuum bag is a great way to store your filament, which is why you’ll see the filament that gets delivered to you in a sealed vacuum bag.

You want to get something that is durable & reusable to really get something valuable.

I would recommend getting yourself the Spacesaver Premium Vacuum Storage Bags from Amazon. It also comes with a useful free hand-pump if you ever want to use it for travelling.

You’re getting 6 small sized bags which should easily fit all of your filament. It squeezes every bit of air out of the bag without letting more back in. You can also use it for your clothing to reduce the space taken up.

Filament Humidity Range for PLA, ABS, PETG & More

An ideal humidity range to store your filament in is as close to 0 as possible, but a value under 15% is a good target.

There are locations where humidity is as high as 90%, so if you are just leaving your filament out in those humid conditions, you are very likely to see some negative effects in your final print quality.

I would make sure to follow the tips above to control for that humid environment in order to get the best quality prints for yourself.

Definitely invest in a hygrometer to check levels of humidity and moisture in the environment where you leave your 3D printer and filament.

PLA does pretty well at humidities even around 50%, but some filament won’t work well at all at that level.

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