What do you find best suits your filament storage needs?

Bambu Lab P1 Series General Discussions
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That’s very cool! But needs a carousel to move beads into and out of the hot spots for more even heating.

As an aside, those no carousel hot spots can be used to determine the wavelength of the microwave energy. The distance between hot spots is half the wavelength. With that and the frequency the microwave operates you can calculate the speed of light. It’s a science demonstration that uses a chocolate bar normally and you measure the distance between melty spots, but this would be cool with a bigger tray of beads to see the pattern across the whole microwave.

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That actually doesn’t make a difference. All you get is a circular pattern of unevenness. :joy:

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But it’s a little better.

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The bigger white bags had been in my dehydrator with the filament for 36 hours at ~125°. Perhaps that’s not hot enough for them?

The little brown packets were straight out of sealed refill rolls.

Since I removed ~4 grams from each roll, I’m wondering if the filament isn’t dried at the factory? I just put all of them in my dehydrator again.

My bulk desiccant showed up today so that’ll get me by.

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Looking at the photo, I’ve seen the brown packets with an “Eco” label before. Usually, those are clay. The ones that look like white powdered sugar packets could be something like calcium chloride, calcium sulfate, or activated alumina.

I do collect and conserve the Silica gel packets that are shipped to me. I know that powdered desiccants tend to “clump” after absorbing moisture, turning them into a cake-like mass that’s harder to dry out. So, I’ve crushed the envelopes in my hands to return them to a powdered state before drying them. Truth be told, I found them not worthwhile because they’re cheap for a reason, they really are single-use. Silica gel is the gold standard in terms of ease of use and easy drying. As for the clay, I just toss them—it’s not worth it in my view, as their per-weight absorption isn’t as good.

I asked ChatGPT to come up with a chart, and here’s what it produced. It’s interesting that it showed calcium chloride to be so absorbent. I guess that’s one big reason my wintertime ice melt turns into a brick if I forget to seal it in a container.

Substance Appearance Moisture Absorption by Weight
Silica Gel Small, clear to white, round or irregular beads Up to 40% of its own weight
Activated Alumina White to off-white spherical beads or granules Up to 20% of its own weight
Molecular Sieve White or grey spherical beads or cylindrical pellets Up to 22% of its own weight
Calcium Chloride White crystalline powder or granules Up to 300% of its own weight
Clay (Bentonite) Light brown to tan irregular granules or pellets Up to 25% of its own weight
Calcium Sulfate White powder or granules Up to 10% of its own weight
Montmorillonite Clay Light grey to tan granules or powder Up to 30% of its own weight

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Cool science trick

Take a teaspoon of silica gel and put it in a shot glass full of water. Weigh it before and after because it will give you a good idea of how much it can absorb. Listen to the sound it makes as it absorbs the water. You may need to put your ear closer to hear it, but it almost sounds like melting icicles when the sun hits them on a winter day. I thought it was kind of cool. Some of the beads actually split apart. After 20 minutes, take them out and pat them with a paper towel to dry off the surface moisture, then weigh them again. Then dry them in your oven or microwave and weigh it again. Repeat if you want to see how much the gel actually can recover. I found it’s not 100%. This is a foolproof way of knowing with absolute certainty what the product can and cannot do.

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Inkbird make some grate stuff that’s cheap for making controlled environments, their humidity control has a long lead for the sensor and will control a dehumidifier left in constant mode by cycling the power to it. I use one of the humidity and a temperature one in a meat curing fridge I made.

They just plug into the wall outlet then you plug the dehumidifier into it. They cost between £25-£50 in uk but are an American firm I believe.

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Thanks, going to check that out!

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Maybe I missed it somewhere (there is a cornucopia of useful information in this thread!) but what is the ideal moisture content for filament, such as PLA or PETG?

Weighing spools to hundredths of a gram before & after drying is a great academic exercise, but on a practical basis (and I publicly admit to being inherently lazy!) I won’t be weighing spools. I haven’t had many problems at all with “wet” filament. When I was using my Prusa i3 MK3S+ originally (and before that, the Anycubic Chiron), with the spool hanging out in the open air, I was printing directly from the eSun drier box. I then enclosed the Prusa in an Ender enclosure, and kept gel packs inside with the printer, and had no problems printing. I’d also run the spool through the eSun drier when done, then seal it in Sistema containers with several gel packs, so that it was dry and ready to roll the next time I needed that filament.

Now with the Bambu P1S with AMS, I keep a bunch of Activated Alumina packs inside the AMS. No problem printing with PLA, PETG or ABS so far. I rely on the Sistema containers (& more recently, the Yashe cereal containers) with gel packs or homemade AA packs, to keep the filaments dry. Haven’t had a need here to keep hygrometers inside each container; I do keep one inside the AMS itself, more out of curiosity than need.

I guess the point I am trying to make is that its easy to go down a rabbit hole about drying filaments, but unless you’re having an issue related to wet filament, I wouldn’t worry about the exact humidity numbers and moisture content. (Should it be 10% or 12% or 20%?) I think the rule-of-thumb is, “Your filament only needs to be as dry as necessary to print without a problem.” Keep your filaments in sealed containers with some desiccant, preferably after running them through a dryer (especially under humid ambient conditions), and you’ll probably be good to go.

For reference, as I sit here writing this at 1:13 am, the RH in this room is 52%. If I take out a spool from the sealed container and place it in the AMS, its exposed to that humidity for all of 30 seconds or so. If the minute amount of moisture that the filament will take on in that short span of time is going to cause a problem printing, then the filament was too wet before I even opened the sealed container.

On a slightly different note, I saw someone posted a note that they were using a repurposed food dehydrator. So I went shopping on Amazon and found a nice unit for under $100 that will allow me to dry at least 2 spools of filament and a tray of beef jerky simultaneously:

Food Dehydrator
Food Dehydrator722×583 106 KB

:yum:

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I converted an Amazon dehydrator but it’s a round one, I made a few riser rings to make it taller so I could ram more filament in it. Can currently get 8 rolls in there and drying at once. I’ve found if you want to make jerky it needs to be below the filament or you will get a plastic flavour incorporated into it :joy::rofl:

This is the one I used.

IMG_5534
IMG_55341125×2436 310 KB

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You didn’t miss anything—there isn’t any public data on the ‘ideal’ moisture content for filaments like PLA or PETG because determining it accurately would require destructive testing. Instead, what you’re seeing in this thread is empirical data, which many find to be the most practical way to gauge moisture levels. It’s less about exact numbers and more about finding what works best through experience.

While weighing filament might seem laborious, it’s the only tool currently available short of the above-mentioned destructive test, and I doubt any of us own a home Karl Fischer titration test kit. :joy: But a $10 kitchen scale isn’t a far reach, is it? But if one wants to really go down the analytical rabbit hole, here is a how-to link on one such procedure. :wink:Karl Fischer Titration Guide for Water (Moisture) Determination Ironically, it comes from Mettler-Toledo a laboratory scale company. So I guess there is no way to avoid weighing things. :disappointed:

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A scale measuring to the nearest gram has worked well enough for me. For me, weight monitoring is preferable to risking a failed print due to moisture. I have plenty of other ways to ruin a print.

I’ve noticed that the meter on my Eibos dryer has usually shown its lower limit of 10% for an hour before the weight loss stops. That might be useful to know if you do not have a scale.

I allow two grams of weight gain before re-drying and have had no moisture problems, but more than two grams might be acceptable for some filaments. No need to measure tenths or hundredths of a gram when the go-no go point is orders of magnitude higher.

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You have sort of a point, but gloss over other issues. Many are using dryers but still having moisture-related problems. A lot of people think putting a spool in a common filament dryer for some number of hours is “drying” the filament. It might be but it might not, too. The big uncommon denominator in drying filament with regular dryers is ambient humidity. Filament dryers using ambient air with humidities ranging from low to high gives results that range from good to poor.

As Olias said, the only way to know how well drying is working is to weigh it. It’s not perfect. We don’t know what the starting water content is/was, but we can know what humidity we dried to and how much water was lost.

It’s really important to understand why we do this stuff before poo-pooing the process and declaring it a waste of time. It may be unnecessary for you if drying in your environment is effective. But for others who are trying to dry in high humidity, your process and procedures may be very inadequate.

And you were probably joking but drying jerky in a food dehydrator with spools of filament is a bad idea for a number of reasons. The jerky would be a water source and slow drying of the filament, and the filament will likely be outgassing various volatile gasses from plasticizers and additives and the plastic itself that will be able to soak your jerky.

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Hi MZip - I wasn’t trying to gloss over other issues nor poo-poo the problems that some others are having. I recognize that some folks do indeed have moisture issues, in which case they need to take the extra steps outlined in this thread. Although in general I don’t have moisture issues here (where during the summer months ambient RH generally runs 50-60%), on exceptionally humid days/rainy days, I try to not run my printers. I’d also say that I use PLA filament for the simple majority of my jobs here, and PLA is not as susceptible to moisture as is PET-G or ABS, for example. The point I was trying to make is for folks to not become obsessed with drying filament IF they are not having problems printing. In other words, don’t try fixing a problem until you have determined you have the problem.

There are a lot of newbies reading this thread, and my advice is to practice keeping your filaments dry by non-extraordinary means (e.g., storing in sealed containers with desiccant to start) until you determine that you need to take extraordinary steps to address a filament moisture problem.

And yes, my comments about jerky and filament spools in a food dehydrator was made tongue-in-cheek. As a general rule-of-thumb here, I don’t bring ANY food or beverage into the room where my printers & computers sit. Want to have a moisture problem? Spill a beverage. :wink:

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…weight monitoring is preferable to risking a failed print due to moisture. I have plenty of other ways to ruin a print.

Hi Ikraus - If you’re in an environment in which moisture is or can be an issue, I couldn’t agree more with you! You’re spot on!

How do you like the Eibos dryer? I looked at it and wanted to order one, but they were unavailable. I wound up ordering a dual-spool unit from Creality which should be here today. If anyone has experience with the Creality unit, I’d love to hear your thoughts on it.

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Has anyone reading this thread tried using a room dehumidifier to address moisture issues? Just wondering if keeping the room’s humidity as low as possible in conjunction with simply precautions such as storing filament in sealed containers with desiccant would suffice for most. Room dehumidifiers are not expensive (a LOT cheaper than some of the filament drying ovens I’ve seen advertised online) and might save a lot of time & effort in the long run.

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I agree completely with this but your post seemed to weigh heavy on drying filament being a “rabbit hole” and not really necessary. If you spend much time here you’ll see all the posts asking for help where it really looks like moisture issues and then all the misconceptions people have about drying (“But I dried the filament for 6 hours.”).

For those having issues, this is all important information. Scales can answer a question about if their dryer is even drying, or worse, adding water (they absolutely can add water). If you aren’t having issues this advice and discussion isn’t really aimed at you and it muddies the water for those having issues and not understanding why to see posts saying weighing or other approaches are a waste of time even when you couch it with “if not having issues”. When people don’t understand a problem they are less able to discriminate between advice that applies to their situation and advice that doesn’t.

That is why I replied to your post. For those not having wet filament print issues drying isn’t necessary. For those that are having issues, good scales and weighing can help sort where their problem is coming from as can paying attention to ambient humidity.

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I’m not going to scan back through but there have been a few people who mention dehumidifiers in this thread and others even have them blowing right at a filament dryer. It does help. Anything you can do to reduce humidity around and in a filament dryer will help reach lower humidity in a filament and speed up how long it takes to get there.

The issue is dehumidifiers are little air conditioners and are power hungry. They use between 300W and 500W when running and generally run for hours. If people have one already for other reasons, that’s great, but if looking at one to help filament drying there are hidden costs that keep accruing. There’s cheaper ways to get dry air for filament drying.

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While weighing filament might seem laborious, it’s the only tool currently available short of the above-mentioned destructive test, and I doubt any of us own a home Karl Fischer titration test kit.

Hi Olias - Oh heavens no!!! :laughing:

I was thinking about the cheap hygrometers folks are using, and just how unreliable they are. Better than nothing. Just hope folks are not getting too hung up on numbers.

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The people who are not having printing issues might be too hung up on numbers, but some are absolutely having moisture issues and getting “hung up on numbers” is probably what they will have to do if they want to solve their water issues.

Again, if you aren’t having water issues, we are not telling you that you need to weigh filament or take other extraordinary measures to make sure your filament is dry and stays dry.

It’s like walking up to a traffic cop and saying “Why are you waving your hands? I don’t have a car.”

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They aren’t unreliable. They just might not be extremely accurate. The sheets that came with the ones I use say accuracy is +/-5%. That’s plenty good for these purposes.

If you aren’t having issues with water, why even concern yourself with this? And now you are sounding like you are ridiculing the process. These are the tools we have. Yes, there are others like the Karl-Fischer test Olias mentioned. If you have questions I’m sure people would be willing to help, but correcting your misconceptions and prejudices is getting old.

Are you trying to derail this discussion because you think it’s stupid? It’s absolutely not. Some people need this information. Again, if you aren’t seeing moisture issues, good for you but please understand not everyone is so lucky.