Unfortunately that doesn’t guarantee anything. Water vapor still leaks in and gets absorbed by filament (and desiccant).
New filament in what looks like vacuumed bags can have any moisture content and be fine or too wet to print well.
The clear plastic bags are semi-permeable to water. To get better protection from water infiltration takes metallized coatings or other more expensive kinds of bags.
But you also say these cards are reversible and show the current humidity the filament is exposed to. It can’t be both.
The cards are reversible and really provide the same information as a hygrometer. The advantage with cards is no batteries. Some of the batteries in my storage hygrometers are so low now it’s hard to read the humidity values.
So really equivalent information but the real utility IMO is in storage they keep working. I prefer the finer resolution of hygrometers but no batteries is the big one for me.
Actually, if you want to know the integrated humidity a spool has been exposed to you can. Without desiccant, the humidity test will tell you indirectly what the moisture content is in the spool. Just test the spool itself.
Its also worth noting that electronic RH sensors are calibrated for a pressure range, usually atmospheric ±10kPa. At low pressure (partial vacuum/negative gauge pressure) they cannot be relied upon for accurate reading for several physical reasons. Sometimes reading high due to outgassing of polymer chemicals that may mimic moisture.
I think the printed cards may be a better tech for this specific application.
I use a couple of “Dewallt tStak1” IP54 toolboxes for storage. (They go for €30 on ocation, normal price €40 on Amazon.)
Throwing in a couple of larger desicant bags and a hygrometer. Not a perfect solution, but good enough for me. The toolbox fits 10 BambuLab refill cardboard boxes each.
A good tip, (witch i have not done my self so far.) is to not store the cardboard as its prone to hold a lot of moisture.
Still working things out my self.
For almost a decade I have been using clear plastic “ziploc”-style bags. When the filament(s) arrive I insert the silica thing inside and as more and more filaments of the same color come I place those inside as well. I have never, ever, had an issue with poor filament because of moisture. I don’t need the vacuum part of the bag, but it comes with it anyway. From Amazon: ELEGOO 3D Printing Filament Vacuum Storage kit, 10 Enhanced Thickened Bags Vacuum Sealed, Dust Proof Humidity Resistant for Keeping Dry with Sealing Clip Without Pump
You’re lucky. Not everyone has the same experience.
Thing is, we know that people with setups like yours exist and that they don’t need to store carefully or sometimes even dry. Telling us about your good fortune really doesn’t help much - especially since you don’t also report things like ambient temperature and humidity or show photos of your models so that we can judge for ourselves how free your prints are from filament moisture issues.
But thanks for letting us know.
Sounds like you aint tryin hard enough!
Those packages of dessicant are not permanent, if they’re silica, they’ll be quickly used up, they need to be regenerated. They may even be adding moisture to your containers if you keep reusing them without regenerating.
I only print PLA, PETG, and TPU.
I store all my filament in Ziploc bags, with no desiccant, and put that into cardboard boxes that filament comes in.
In over 11 years of 3D printing, I have only had to dry Nylon filament (which I don’t print any more) and perhaps 3 or 4 spools of filament that came moist out of the box. When I got my P1S in March 2024, I thought I would try some translucent red PETG that had been sitting in the box/bag for at least two years. It printed flawlessly.
The humidity in my printer/filament room varies between 45 and 55%.
What printer are you getting those great results with and can you post a photo of your models?
Reason I ask what printer is with an 11 year record of no issues, the majority of that won’t be a Bambu printer.
My old printer worked without drying filament too but the prints still showed water issues. I just didn’t realize it. It was slow.
The Bambus print fast and that seems to be a factor in water issues. Have you done any printing on a Bambu? Are you using Bambu filament?
With a 45-55% ambient humidity and undried PETG, I have a hard time understanding how you are using PETG without drying and getting good results on a Bambu printer. That’s certainly not my experience.
Can you provide more details and photos of what you print like that?
Here is a test with some weird results.
Items used :-
2 x vacuum bags 1x food rated (Blue zipper), 1x filament rated (Grey zipper)
2 x dried 20gram desiccant bags
2 x digital humidity meter
2 x paper type humidity meter
2 pieces of folded paper kitchen towel
1st Step. I dripped 10 drops of water onto a kitchen towel. Inserted the damp towel, a digital humidity meter, and a paper humidity indicator into both bags. Lightly squashed and sealed the bags using their zippers.
I then let both bags sit for 24 hrs to establish a max humidity, blue bag 86% grey bag 82%
2nd step. I then inserted a 20 gram desiccant inside each bag. After 24 hrs the blue bag indicates 58% and the grey bag 43%. I also measured the weight of the desiccants. The blue bag is now 22 grams, the Grey bag 21 grams.
A 20gram desiccant can absorb 20% of its own weight, so 20 + 20% = 4grams (4mL of water)
1 drop of water is ~ 0.05grams (or 0.05 mL), so 10x drops = 0.5grams
The grey bags desiccant weight has increased by 1g so 1/0.05 = equivalent to 20 drops of water!
The blue bags desiccant weight has increased by 2g so 2/0.05 = equivalent to 40 drops of water!
I’m confused! These results are not what I was expecting. I was expecting the desiccants to absorb the 10x drops and the humidity to be fairly low.
Since writing this, I have put two 20gram desiccants open, in the room, to see what happens. I am thinking to repeat a test, but using a sealed glass jar. Any better ideas?
Was the desiccant that you put in the bags dry? How do you know? Fresh dry desiccant and a hygrometer pulls bags here down below what the hygrometer can measure - 10%. Did you test the desiccant before?
Thing is, desiccants are very powerful in just air. They can hold lots more water than air can. You can calculate the water weight of vapor in an air sample from the relative humidity and there’s not much in things like gallon and quart containers even at high humidity. Desiccant way outguns air for holding water.
Most plastic bags are semi permeable to water and water can be leaking in while you do your testing. For a first run and to test procedures, I’d suggest using thick wall cereal containers to essentially/mostly eliminate water errors from virtual leaks.
I know you are wanting to test plastic bags but you need to get your testing methodology to work in easier conditions first now that you’ve gotten inconsistent results.
Hi, you are completely right. The initial idea was simply to compare the old bag that I have been using to a new bag. Supposedly of better material and better sealing. I decided to not vacuum the bags.
I’m pretty sure the desiccant was dry (correctly weighed 20gram) But will repeat using a suitably sealed kitchen container and over dried desiccant. I need to establish a good reference point. Start over again!
You learn a lot doing stuff over, though. It’s about the only consolation but how often does anything work first time? But for learning what’s really going wrong, the experiments that fail can be more valuable than the ones that work.
Please post what you find! 
What printer are you getting those great results with and can you post a photo of your models?
Two different printers; a P1S and an Elegoo Centauri Carbon. I no longer have the P1S, as the power switch failed, and when I figured out how much effort and time it would take to fix, I sold it and picked up the Elegoo, primarily because of the price.
My old printer worked without drying filament too but the prints still showed water issues. I just didn’t realize it. It was slow.
I started in 2014 with a bed slinger designed by a fellow in Regina. Bought it as a kit and built it.
My second printer was a Delta. I gave up on that after a few months. Never did get anything good out of it.
My third printer was a Hypercube Evolution (CoreXY), which was much better than the bed slinger. Bought it as a BOM through AliExpress. All three printers took 3mm filament.
On all three printers, I used plate glass as a bed, and always used a Pledge floor cleaner that also left a coating, and later, used Kamar Varnish.
Reason I ask what printer is with an 11 year record of no issues, the majority of that won’t be a Bambu printer.
Well, there were definitely issues, but not with humidity. I spent a lot more time messing with the printers than actual printing. The P1S, which I bought in March 2024, was a marvel. I did not have to do much with it to get prints that far exceeded the quality of anything from my other printers.
I only used a couple of roils of Bambu Lab filament that I ordered with the printer. Contrary to what most folks got with the printer, they sent me a 1kg roll of PVA support filament, which I never used and had no need for. Ended up selling it to a fellow in Virginia for $5.00 plus postage. I did that because I just hated to toss it in the garbage.
With a 45-55% ambient humidity and undried PETG, I have a hard time understanding how you are using PETG without drying and getting good results on a Bambu printer. That’s certainly not my experience.
When I first started printing, I did use desiccant in the Ziploc bags, but slowly decreased the amount until I was using none. Sometime in 2015, I made a dryer out of a Salton food dehydrator and a modified 5 gallon bucket, and used that for nylon, which REALLY needed drying, and for the few rolls that came too moist out of the box.
Can you provide more details and photos of what you print like that?
I can try. It’s hard to see the layer lines, and I print mostly with PLA. Here are two prints; The black one was printer very shortly after I got the Bambu Lab, and the green one I printed just a few days ago with the Elegoo. I don’t remember the brand of PETG I used for the black one. The Green one is Creallity PETG.
I could not get a good picture of the layer lines on the green one (hard to focus), but the black one shows the lines and the change in surface sheen due to layer time changes at the height of the knob.
The Bambus are pretty fast printers which is probably why water affects them the way it seems to. Maybe the design of the extruder factors, too. But it’s apples and oranges to try to bring other printers into discussions of printing with Bambu printers.
It doesn’t sound like you don’t know the moisture content in the black PETG spool you used on the Bambu printer. If it was new and happened to be dry, there is no reason you wouldn’t get a good print. I’d like to see prints done using filament you’ve left out for about a week or more.
Was it a new spool and did you do anything to get a handle on its moisture content?
It’s also helpful to drop the humidity in the space.
I use a “Midea 4,500 Sq. Ft. Dehumidifier With Pump Included”. It pulls water from the air and pumps it out into the flower beds. It goes down to 35% in fact, though mine is currently reading 40.
It doesn’t eliminate moisture problems in my AMS’s or in my filament storage, but it does dealing with them easier and less time consuming.
I don’t think it’s apples and oranges when speaking of humidity and storage of filament.
I only had my P1S for about 3 years, 4 months, but by the time I bought it, I had already gone to storing filament in the way I mentioned. Cardboard filament box with Ziploc bag inside, no desiccant, and have had what I consider to be excellent results.
It doesn’t sound like you don’t know the moisture content in the black PETG spool you used on the Bambu printer. If it was new and happened to be dry, there is no reason you wouldn’t get a good print. I’d like to see prints done using filament you’ve left out for about a week or more.
I do not know the moisture content of the black PETG. It was likely printed from a Bambu Lab spool that I got with the printer, and yes, it was probably dry. But I did print something shortly after the arrival of the P1S using a translucent PETG that had been sitting for at least a year with my usual storage method, and may have been even longer. The reason I don’t remember is that I broke my hir and had a hip replacement in Jan 2023, and was unable to do any printing in my printer room, which was in the basement. When I recovered enough, bought the P1S, I resumed printing.
Was it a new spool and did you do anything to get a handle on its moisture content?
I really don’t remember, but I will try to get a print using that same translucent filament stored before Jan 2023 at the least.
Would you like to send me a link to a fairly small model to test with the translucent PETG?
Be careful with those dehumidifiers, it’s real easy to rack up power bills. Waters latent heat is incredible. Mine is a biggish “50pint” one, and it runs at 700watts when cycling. If you tell it to haul ■■■, that is $125 of electricity on your bill (at my utility rate of $.25/kwh)
But it is. One of the features of Bambu printers is print speed. With higher print speed comes faster feeding of filaments which can provoke water issues. Slow printers seem to be more forgiving of filament moisture. It is apples and oranges unless you have printers doing so well with the same filament feed rates as Bambu printers.
As I related, I saw this myself. My old Makerbot printed fairly slow and I did open storage with my filaments. There were water issues evident at times but at the time I didn’t recognize them because I was unfamiliar with water issues. When I got my Bambu those filaments that had been stored in the open would not print well and I bought new filament.
The printer does matter. My Makerbot printed through the water effects. My Bambu won’t. I can’t get consistently good prints without drying on my Bambu. I never dried with the Makerbot and generally got great prints — but it was very slow.
I’m not going to try to solve this with you, though. If you are getting great PETG prints without drying and with open storage in high humidity, you and your setup are indeed unique because few make those same claims. Many posts here about PETG are because people are having water issues. I’ve seen water issues and I have tested my filaments for water content and developed my own routine to get rid of water and get good prints.
Your experience that you relate just does not fit with mine. I don’t know why but with all the intermixing of non-Bambu printers and filaments, and reluctance to just answer direct questions, I’m not going to spend any more time with this. I know what I’ve tested and how, and I know what my results have been. If you ever determine why your results are different, you ought to tell others.
I have the P1S and have had excellent results using the same method, (using the cardboard box the filament arrives in with IKEA ziplock bags and the desiccant the roll arrives with). As far as I know I’ve never had an issue with moisture.
I only use PLA and the only issue I’ve ever had was with the filament getting brittle over a long time. I’m talking years in this case with a colour I rarely use. My solution was to unwind a few metres off the roll and use it from there.
I use mainly Bambu or SULU filaments.
So after reading this post I guess I’m lucky.
