I would be curious to see the same test, but this time add in "after drying" categories via dry box or oven/dehydrator. Just to see how well it actually removes the moisture vs just keeping the filament bagged away in the first place.

I can see his teleprompter reflected on the PSU lol. Was wondering for way too long wtf that movement was

More than one of the old time welders I knew had an old refrigerator with the compressor disabled and a 100 watt incandescent light bulb on in it to store the "sticks" in. The working refrigerator had the beer.

Steam bubbles breaking the polymer chains - first time I've heard that explanation and it makes a lot of sense, thanks! Recently noted on a challenging ABS print (major buildup of internal stress) that I was getting delamination despite excellent print quality and printing very slowly at 260C. Just switching to a newly bought reel of ABS and no delamination at all!

After drying I only see a difference in layer adhesion and in stringing. I am glad that you did this, and it confirms that my process of keeping filaments in their bags with desiccant is likely enough for the casual prints.

Loved that you put this up and included all of the background data. I read it as both the weight gain and potential strength loss are within the noise margins of your tests, and that's OK. That there are clear functional and appearance differences in printing, even with PLA, was great to learn. I live in the northeastern US, where it's very humid in the spring and fall, when the temperatures are mild. So we may see an indoor relative humidity of 45% or more. I've wondered if I'm being overly cautious in keeping all of my PLA in bags with desiccant, and it turns out I haven't! Thanks for this.

Recently, I have gained the impression that manufacturer-specific additives to the filament matter much more than the actual base polymer (or to a similar degree). I have printed a bunch of PLA, ABS, HIPS and PETG. PETG appears to pick up moisture pretty quickly from every manufacturer, on the other side of the spectrum, none of the HIPS-filaments I tried appear to care much about it. But with both PLA and ABS, I have spools that have been out in my printer room for months and they still print like on the first day, but also spools that will start bubbling significantly just after a few weeks without drying.

I remember when I got my first spool of nylon. Instantly turned my hot end into a steam engine, and that was right out of the vac-pack. Such a pain, but worth the work if you need awesome parts.

I'm glad you are covering this. I had a spool of Ultimaker PLA filament out in the open for 8 years. I decided to print with it and wow, stringy! I invested in a Print Dry Pro filament dryer and after 6 hours of drying, it printed very well! At work (home of the world's largest 3D printer), we dry the pellets for several hours before use, then they are loaded into the printer. That got me thinking about the weird print issues I would see on my home printers. I now dry all my filaments before use, no matter how amazing the vacuum packing looked. The results are way better! Also, active drying is the way to go. Sitting in a tub of desiccant wont do a thing, you need to actively heat it up to get the moisture out.

Hey Thomas, thanks for covering this. It's really great to see folks like you and Stefan over at CNC Kitchen trying to approach these questions in at least a relatively scientific way (including recognizing when your results just don't show enough significance to draw a conclusion). This is an area that's of great interest to my university lab, since we do a lot of prototyping with 3D printers. One subject that we've begun to explore, and there really doesn't seem to be a lot of readily available information on, is the effect on mechanical properties of moisture absorption post-printing. We did a brief (unpublished) study of a carbon-reinforced nylon where we printed a group of samples at once and tested groups of them at varying time intervals. It showed that the elastic modulus dropped by almost half within a week of printing. We haven't repeated the study for any other common materials, but it's certainly a result that warrants some further investigation if you're looking for subjects for future videos. Again, it's not an area that we're *particularly* interested in publishing results, since we focus on the structures we make with 3D printing, rather than the process itself, but there may be some potential for collaboration or sharing results if you're ever interested.

Thank you for all the time you took showing this test. I’ve been having major problems printing petg after it being my favourite filament for months. It went from perfect prints to not usable in a few months. Even drying it for 20 hours does not give the same strong layer bonds anymore.

Love this video. The panic that seems to surround "wet filament" is pretty extreme. I get regular comments about my filament being opened. I even get comments that I shouldn't open the bags, which makes it rather hard to print with the filament.

Hi Thomas, I always appreciate the way you are looking at those things - that level of detail is really mind blowing. Thanks for your work!!!

Great effort, thanks. I do print a lot of PETG, so I think I'll start running it through my dehydrator if I'm planning on any major printing sessions.

This is the first video in MANY years which has a sponsor I did NOT skip. Thank you!

Before I started I already said to myself, I don't care what he is going to say I have absolutely no issues with how I do it now. Just open in the air nothing special. Glad you had the same conclusion.

with a 0.6 nozzle or bigger having dry filament is essential if you don't want the most obscene amount of stringing known to man. I had some PETG and I couldn't even make any functional parts with it with my 0.6 nozzle because it would ooze too much. And then when I dried it out it worked absolutely perfectly. I was even able to lower my retraction quite a bit.

A couple years ago I had a hotend collision with my bed and damaged my build surface. Long story short, it took me two years to get around to fixing it. So I have a two year old roll of pla that is still on the printer. I started printing parts again yesterday and the prints are flawless.

Good info as always. I'm also curious why the 300mm or so of PLA left inside a Bowden tube seems more brittle than the material coming off the spool.

Interesting results! Inconclusive is better than I expected. I have an old roll of PETG I'm trying to use up, I'm really struggling with layer adhesion and warping compared to the same material from a fresh roll, even after drying it for almost a day

Great video, thanks as always for the informative and interesting content. I did want to say, though, to not fall in the trap that many scientists do that a lack of difference is a lack of results. Failing to reject a null hypothesis doesn't mean an experiment failed, it just means you didn't see what you expected. That is still extremely valuable information and it should be published! Thanks for publishing your unexpected results, they provided some really informative data.

Great video Tom! Love your dedication to the research and testing! Octolapse can be picky with print settings. We find when we do time lapses we have to cut temps by around 10C or more to keep that oozing down. Interesting about the smell of the ASA, I wonder if my old ASA and ABS will smell worse than new! Great video as always Tom! Love the detail here!

I also have an eibos dryer and I love the heck out of it. 2 years ago I bought a prusament PETG and was never able to print it properly. After drying it it magically started working completely fine. Ever since I have it I print directly out of it and dry my filaments during printing.

Great content. Thank you for putting in that high effort to give us this helpful conclusion.

@Thomas Sanladerer: Thanks for doing this research. Hope to see more in the future. Glad you're acknowledging your biases and experimental flaws, that's important in science!

In my case, the biggest issue I seem to have with filament that's been left sitting out isn't necessarily print quality (although I have some stuff that's got a lot of stringing) but brittleness. Hard to get a good print when the filament keeps breaking before it reaches the extruder.

One thing that this video taught me is that the community as a whole is saying "You filament is wet" far too often. Apparently your filament can be very wet and still print fairly normally.

One more thing to consider is that the mechanical properties of the printed thingy can actually improve after absorbing the moisture. For example nylon to have the expected "nylon" properties, it needs to be allowed to absorb at least some moisture. So the moisture might not be good for the print, but is part of the operating properties.

Storing filament outdoors also exposes it to UV light, which could have its own bad effects. I usually store my filament in a closed zip lock bag with a packet of moisture absorber that usually comes with the filament. I haven't done a very good examination, but stored this way filament that has been opened seems as good as brand new. But then again the stuff I print isn't critical.

as you mentioned drying, I‘d be interested in seeing how effective putting the filament on the hot buildplate and covering it is with that

that opening shot.. just another level.. awesome.

Thank you. I was blaming my failed prints on “moist” filament. That is until I made a filament dry box. Inside the dryBox down to 17% humidity and my prints weren’t any much better. I found my problem was due to heat creep up the heat break and messing up the end of the Bowden tube. So I ordered new style Capricorn YS (I think) Bowden tube to try. And steel nozzles

As someone that prints in a garage in Florida, I appreciate this video...

Pretty interesting stuff, I'm new to printing and have only had my printer for about 2 weeks or so. I've gone through almost 1kg of PLA so far that has just been sitting on the machines spool holder. I don't think the humidity is very high and the only issues I've had with print quality seem to be from my inexperience. I've been having a lot of fun printing random things and little tools, I've also been enjoying the process of learning new things!

Download the datasheet for each plastic. It will give you optimal temperature for molding as well as what temperature and for how long you need to dry them. I've been doing injection molding for 20 years and we dry all plastic before use it there are a ton of problems/defects that can result.

Super informative. Thanks for performing the testing!

from my experience with pla, I have left the same spool of filament in my garage unprotected from the elements in the florida humid weather for 5 months. Used it without any changes to the spool and it printed the same as a new roll

Excellent to see some testing. Never assume factory "fresh" PETG isn't wet. I've had filament that came sealed with dessicant from a number of vendors that needed many hours of drying to stop seeing bubbles in the nozzle stream. Transparent and semitransparent seems to be worse than solid colours for some reason.

This was a perfect collab opportunity with CNC Kitchen!

Hmm glad you did this test. I'm half way through an ASA spool in the winter and it has started to pop and bubble coming out of the nozzle and I assumed it was saturated with moisture. I can't even get the first layer to adhere at this point since the plastic barely bubbles out the nozzle. Probably time to order another spool unless I can use a dehumidifier or something to recover it.

More testing to be done. I've done quite some moisture related tests at my workplace while using professional hardware. The variations in moist levels can be quite significant and can be checked with a good scale. I've recently had an old spool of tpu dried (~500g) and checked pre and after: more than 15g of water! Some materials don't "moist" very fast, we usually saturate test samples in heated water in climate chambers. Cold water does take too long 😄 Outside test: you can freeze-dry clothes, so maybe its even better stored outside?

Thanks for great video! I was always wondering how humidity of filament affects the print quality and now I got the point.

As usual, AWESOME Video! Your testing controls were well thought out, based upon your available tools and measurement limitations. There is one aspect that I don't think I hear you mention, did you have your dehumidifier running during testing? If so, would there not be a tendency that at all the samples would try to 'normalize' to the environment; i.e. get drier? That is, the longer that remained in the room environment, the samples would all eventually establish the same humidy level - time being the variable factor? Your thoughts?

What a great test setup! Well done! That shirt looks SO comfy, btw.

Very informative. Thanks for making this video!

Thanks Thomas! Very informative.

THANK YOU FOR THIS VIDEO!

Really interesting. Thanks!

Thank you very much for the interesting video! My printer room is fairly dry, but to be on the safe side I will dry the spools lying around tomorrow and store them away properly.

Thanks for including ASA! It's my favorite filament and what I use the most, and it's rare to see it included

thank you for a fascinating study!

I've had bubble issues in clear TPU that made it translucent. I didn't know that it was that sensitive. Printing dry looked great.

Great video! I thought that it wasn't that important after some filament I have had out for 4 years works pretty well. To be fair, the humidity here is often 40-55% rel.

man I freaking love your sweat shirts.

My practice has been: - open bag - remove tiny desiccant - dry filament - put back in a sealed bag with larger (colored indicator) desiccant - move on with life I usually go for visual quality, so I know from printing out color swatches (that have a lot of retractions), dry filament is leagues better then straight out of bag (let alone wet) filament. But once that's done, I'm content. An interesting one for me was I was told by one filament manufacturer that there is a limit to how much you can dry filament before it starts to degrade and they recommended no more then 3-4 drying sessions (couple hours each time) for the entire spools lifespan. They use Natureworks PLA (don't remember the exact number).

Great vid! and nice presentation. I like your humble approach and you "not totally scientific" tests. I do similar tests with drones and antenna reception ;) I'm new to 3D printing and love how much this has improved over the years - so it's very easy to start now!

can someone tell me why on my ender 3 pro, the first layer has trouble sticking to the mat. It looks as if the PLA grabs onto the hot nozzle then it peels itself off, more common with smaller parts, but still relevant in bigger projects.

Great video but i have an issue i've got some old school Esun filaments in ABS/PLA and they all brittle AF i live in the Caribbean it's hot here i even put the filaments in a 5 gallon bucket with 2 7watts heat pads and still after a month it's still brittle what can i do please anyone help thank you or the humidity here is high like really high

Thanks Tom, great video well done

Excellent content. Did you notice the hydration altered how well the materials stuck to the build plate? I haven't done any specific testing, but historically I've had serious issues with PLA, Nylon, PETG, and PC sticking when they absorbed water.

Thanks for putting this together. Great video. Ive always been a little curious if letting a filament get wet, then drying, is any worse than just using it dry out of the box.

Thank you for including ABS. But what stands out most to me is the dimensional accuracy, Specially if you make stuff that need to fit or slide together. Any chance you could take a caliper to the chimneys ?

Glad to see this. Im actually a medical and aerospace engineer doing a full punlished study on the food safety qnd sanitation of 3d printing. I get to use a SEM scope often and some of the most dangerous bacteria. Ill be posting some youtube videos soon, discussing my findings since its for an internship.

Super interesting video Tom, thank you so much! 🧡💜

Thanks for this one. I'm looking forward to you testing the new Prusa XL ;)

Well done!

For whatever it's worth, I notice an extremely significant difference in surface quality and stringing when printing with eSun PLA Pro that has absorbed water--especially when I'm printing minis with a 0.25mm nozzle. So much so that I dehydrate all my filament first and feed it from a drybox to get the absolute best minis I can. And the difference is really noticeable.

I've had PLA that was left out in the open for a few weeks pop holes in the outer wall of the print. You could hear it popping while printing. Stick it in a dryer overnight and the problem was resolved. The moisture in the filament was being turned into steam in the hotend and popping holes. I live in a dry part of Australia.

I don't know if it was Sydney Australia's humidity, or kept on a roll, but both pla+ and cheap PLA still in the bag clogged up the PTFE tube. When I replace the PTFE (better than the Anycubic basic material) as it could be something else, but will try with fresh PLA+

Could we have some close up images of the difference between the fresh and indoor prints?

Waiting for your Eibos Cyclopes test. ‘My Tech Fun’ did an excellent dryer test that convinced me to buy one myself. Very happy with it too.

I have that scale. I hade to calibrate mine. But now it works fine.

Great video, awesome to see your efforts. I just had a thought. You may see more accuracy with the filament weight measurements if you increase your sample size. For example, use a whole spool as a single sample. This is more expensive to conduct, as these tests are lossy. But, it would give a rough idea. What do you think about moisture causing filament to become more brittle over time?

so me that i leave out my place on the printer for the last 30 days is bad? and if so how can i dry it in a oven dont have a filament dryer

I managed to accidentally do the same experiment. I had most of my filament and printers in storage in an unheated garage in Oregon for a year. During the time this filament was in storage, the humidity meter fluctuated between 75-95% humidity, with temps anywhere from 35F-75F. I had Hatchbox and Taclink PLA stored in the open, along with some eSun PETG and some generic TPU. Every roll of Hatchbox PLA ended up being just fine, and I was able to print high quality parts with all of it. Taclink's PLA would print fine, but the filament became super brittle. It would often break in the bowden tube during a print. Dehydrating it didn't fix the issue, so I ended up having to throw out the entire lot. Both the PETG and TPU printed terribly without dehydration, with a ton of bubbling and popping. Putting them in the dehydrator for a couple hours brought them back to normal, however. The Taclink issue is puzzling, because I remember getting super-reliable prints from it before it was stored. I'm assuming that there is a subtle formulation difference between it and Hatchbox. To be honest, Hatchbox black PLA is my usual workhorse filament, so I'm not surprised that it did better.

I just pulled out some filament that had been stored out in the open in a storage unit for 1 year, in an unused backroom of my first house for 3 years, and then in my basement of my second house for another 3 years. It printed fine.

I'd like to see these same tests with longer term exposure to the elements. I've got rolls here that have been open for months because they're a colour/material combo I don't print with often, can't get anymore so don't want to waste. And I definitely notice the difference in rolls that have been out for a few months. I've even seen it come straight from the manufacturer that way, too - either because they have a crappy packaging process and left the spools out in the warehouse for weeks before they bagged and shipped them out or the bag got burst on the way over. It's just my normal practice now to assume all spools are moist and throw them in the food dehydrator overnight the day before I want to print with it.

Can the AMS be used to keep filliments dry? I am purchasing the x1c next week . Also,if i used a dry box instead to dry my filliments,and i i dont use all that filliment in one run,do i need to dry it again before i use it next time depending on how its stored? I just planned on keeping my materials in a tight sealed box with desiccant bags.

The first thing I had to do when I switched to home extruded PETG is that I needed to keep it very dry, with other PETG's I am not sure but I would assume the same or they added stuff to help with absorption.

The main thing I noticed was that certain PLAs would just jam in my Prusa Mini when they used to print fine. An overnight stay in the dehydrator will make unprintable silk PLA print just fine. As some others have noted, it really seems to vary depending on the source and color. And I live in a semi-arid climate where indoor humidity is typically 20-40%.

I'm living in a badly ventilated apartment. Currently we don't have any tumble-dryer (or any other enclosed area for drying) and during the winter we have to dry clothes after washing in-doors. To that, add heat and humidity from cooking etc. It is not uncommon for us to have a relative humidity sometimes in the upper 50%. As I was a beginner with 3D-printing I didn't think/know about the problem with water absorption, but I can tell you that keeping my Prusament PETG lying on a shelf without any bag or humidity protection made it unprintable. Details less than 5mm broke off very easy (sometimes couldn't even remove supports without breaking it), the surface was extremely rough, a lot of stringing. It was also clear that any kind of retraction gave a lot of artifacts and weak areas. Printing continuous parts ended up semi-ok. I bought a drybox, dried the PETG over night and every print come out beautifully now when storing it properly. Barely any stringing, smooth surface and parts are generally much stronger. I think if you really want to see wet filament, store it in upper 20s with 50% RH for a month. This is not that uncommon climate in badly ventilated apartments during the winter when there is limited possibilities for opening windows etc.

Moved from the desert to right next to the ocean. My large collection of filaments have been in the garage going from below freezing to pretty warm with 90+% humidity. Guess I'll find out what survived.

Hello there can y guys help me I bought riprepguru I3 printer I assembly it and upload code but it won't start it's doing nothing what should be a problem

I keep my open filament in a box with silica desicant and it does a good job, I only actually dry intentionally if I notice signs of moisture on the results. Like egregious stringing or bubbling and popping. Can only really speak to PLA and PETG but I think my system works well. Just gotta do a small test print every time you put an open roll that could have absorbed some moisture on to know quickly.

Very informative.

I have some filament that literally bubbles and pops. Makes a nice pop pop pop noise. I did a vase print with it and it turned out pretty cool with tons of holes in it. You can't even tell it's an fdm print since the lines are all destroyed.

I never worried too much about moisture , I keep my filament (Usually PLA) in a vac bag and inside a cupboard to keep it clean and away from UV light . The same goes for the printer itself - it lives on a bench and has a Creality enclosure that has had the bottom cut out over it to keep the dust away from it and it also allows me to use a small fan fitted to the enclosure to suck out the fumes and pump them outside via a flexible pipe while printing .

4 years ago I buy a printer with abs filament, I didn´t use the printer so I keep my filament (ABS) open in a moist room for 4 years, now I bought a new printer and I can finally use it, and remember that I got that storage filament, so I use it, at first is good, but as it prints the second and third an so on, starts to take off from the bed, so i wonder if thats the problem , the long term storage?

Is there a recommendation of 13:16 humidity range to aim for in storage?

Good video! I have build a printing corner in our shed that tent to get cold in the winter. I'm isolating it with a central heating system now, but it gets moist here. How about a test in a moist envoirnment and how long it will take if you print 1kg a week from a spool to see what the quality will do in that week?

I might make a video on this soon as well. I have some creality PLA that went bad in less than 6 months. Tried to print a squid game doll for my daughter and it kept failing because of heaving stringing on supports. I have a dryer coming and will see if that helps.

How quickly will it dry in a sunlu drier? Is like one hour enough, or just it be days?

To me, the only significant data points are the quality, and the potential outlier of PETG being outdoors; which indicates cold may be a factor more than humidity. But the last one is...one point of data. Very good high-level analysis of the effects of humidity; thank you.

A couple of things I've noticed: If you use a very large nozzle (e.g. 1.2mm) to just extrude some non-opaque PETG into air, it's incredibly easy to see steam bubbles in the extruded filament, unless the filament is nearly perfectly dry. And also, some/most PETG I've tried (although I haven't tried prusament) isn't dry enough to not show any bubbles even when taken out of a new, sealed bag and immediately used. I have to dry even new filament first, to get a no-bubble extrusion.

@Thomas I wonder if I could just put my filament in the fridge and freeze dry it? Of course you would need to warm it up before use in a ziploc bag to stop it being brittle.

Might have already been suggested but you could try using one of the humidity monitors that woodworkers use for the before and after?

Like the thumbnail picture. A play on Dali's Atomica photograph. Excellent!

hi, great video! Any change in future you will do a review of eibos dryer (and maybe some others?).

If I dry silk pla to much does it make it brittle?

I would have liked to see what drying method is best to restore the filament. Good Video about the influence. Thx