It’s no surprise that the quality of your 3d printing filament can make a big difference in the quality of your prints. That’s why there has been a lot of debate about the best way to care for and store your filament.
There is no debate, however, on the one main enemy to 3D filament… humidity.
There are countless stories on the internet of makers who find their new filaments ruined from moisture in the air. It’s important to note that some filaments are more susceptible to humidity than others. For example, PLA, PVA Support Material, Nylon and ABS are particularly sensitive to moisture in the air.
Why you should care about filament storage
1. Filament degradation: Certain filaments are more sensitive to moisture in the air because they are made from materials that easily absorb water. For example, PLA plastic is biodegradable and made from natural resources like corn or rice. While this is much better for the environment than other plastics, it also means that under the right conditions, it will break down into carbon dioxide, water, and methane. Humid conditions and UV light speed up the breakdown of the filament which weakens it and causes inconsistent or poor quality prints.
In their blog, RepRage talks about an experiment where scientists tested how long it takes for PLA to absorb water. They compared the weight of filament before and after it had been submerged in water for 30 days and it absorbed as much as 60 ml of water! If you live somewhere tropical – you may want to consider keeping your filament somewhere airtight to prevent it from absorbing the water in the air. Nylon is also extremely absorbent and will also become saturated with water in as little as 18 hours of being in humid conditions.
2. Printer/Nozzle Jams: One side effect of filament absorbing water is it expands in diameter and weakens the surface of your filament. When you feed this through your printer it can cause nozzle jam. Just like rice expands when you cook it in water, this filament will expand and will eventually be unusable as it can no longer fit through your printer properly. In extreme cases it could even ruin your hot end. It’s good to take a measure of your filament diameter if you think it’s absorbed any moisture.
3. Lower quality 3D prints: When water is absorbed by the filament and it is heated by the 3D printer for extrusion, the water combined with heat makes steam (you will hear a hissing sound as steam is created). This causes the filament to bubble as it comes out of the hot end and leaves you with inconsistent surface on your print.
Picture from eurekadrytech.com
4. Weak filament & breakage: The more water the filament is exposed to, the higher the chances of filament breakage. Although water weakens the filament, the real problem is when you re-heat filament that is wet through the process of putting it through the hot end of the 3d printer. Research shows that printing with wet filament reduces its strength by 33%!
Of course, the degree to which your filament is affected by humidity varies depending on the type of filament you are using. PET and ABS are not as sensitive to moisture absorption as Nylon or PLA. However, keeping all your filaments in a water-free environment won’t hurt.
5 Tips to Keep Humidity Away From Your Filament
There are conflicting opinions on the perfect humidity level for your filament but it should be safe anywhere between 10-15% humidity. You most certainly don’t need to spend a ton of money on a fancy dehumidifier and filament protection systems. Many Makers have taken it into their own hands to make their own filament storage kit like Stephen Hall and his air tight filament container . Here are a few cheap and easy tips we recommend:
1. Use desiccants to absorb the moisture: The most effective and well documented desiccant for keeping filament dry is silica gel. These are the small packets of moisture absorbing gel you find in your shoe boxes and vitamin bottles. You can buy silica beads that will change colour as an indicator that the beads have exceeded a certain amount of water. Once the beads change colour, you can put them in the oven for 3 hours at 120°C and they will turn back to their original colour for you to re-use. To store the gel, put it in any container with holes or slots for air. You can 3D print one or some DIYers use empty plastic containers and poke tiny holes in them.
Rice is also a mild desiccant and can absorb small amounts of water. If anyone has ever dropped their phone in water, you may have heard the trick to put it in a container of rice. It really does do the trick! For this purpose however, it isn’t as effective as silica gel at absorbing humidity from the air. If you live in a humid climate we recommend going with silica.
2. Use vacuum- sealed bags: These are quite different than Ziploc bags as they have an opening where you can stick your vacuum end in it to suck out all the air. No air = no moisture or other elements ruining the quality of your prints! To use your filament, you’ll have to take it out of the bag and reseal it after. Make it even more effective by adding a few packs of silica gel to the bag!
3. Air-tight buckets or containers: This is an alternative to vacuum sealed bags and could could be anything from your pet food containers to large buckets you can get from any home hardware store. There are lids with dehydrator built in called gamma lids which you can also get from a home hardware store. According to a conversation on the RepRap Forum, the 5 Gallon buckets can fit 4 spools of 1Kg filament.
4. Do not keep more than 12 months worth of filament: Naturally, filament quality will degrade over time regardless of the steps you take to keep moisture out. It’s best not to keep too much filament around when you don’t plan on using it in the next year.
5. Store in a dry cabinet: There are dry cabinets and dehumidifiers on the market that work but we recommend to dry a simpler solution first. If you have a ton of filaments that you use all the time and want to store in one place these may be a good option for you.
With all these new types of filament on the market, it’s hard to know how to care for each one differently. We recommend, when in doubt – keep it in a dry, cool place. If you’re interested in knowing more about different types of 3D printing filaments in general, check out our 3D Filament Guide by 3D Supply Guys:
Share your DIY Filament Storage Solutions!
Do you have a trick or DIY solution for filament storage? Share it with us in the comments below.
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