3D Printing Filament dryer recommendations/Experiences
- Thread starter Conway Stevens
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Here's what I do to dry and keep dry my filament. It's what I've done for the past 7 years.
My secret weapon against moisture - 3A molecular sieves.
3A molecular sieves are the strongest desiccant I can readily find, and they're thirsty down to 0%RH with excellent retention, unlike Silica gel which wimps out around 15%. Using molecular sieves, I don't bother to heat my filament to drive off the moisture except for when I'm in a hurry or like in the case of a spool of ABS that was sitting in my shop for 3 years. (and then it's just an hour or two sitting in the bag (see below) on the heated bed at 80c.)
Here are 3A Molecular Sieves at Amazon, the first result is what I've most recently purchased, and that was in 2021, so they last a long long time.
New sieves should arrive activated (dried), but they're incredibly thirsty and will fill up and eventually lose effectiveness. To reactivate the molecular sieves, I place 100g of them spread out on the bottom of a 8x8 Pyrex dish, in the microwave in 3 minute cycles until the weight (of ones that no longer dry below 20%RH - not fully saturated) decreases by 10% or greater. Your Microwave May Vary. Usually this is done in 3 cycles, or about 10 minutes including the time to weigh them. Why the intervals? These guys get EXTREMELY hot. They can even glow, and leave divots in the surface of the Pyrex from melting the glass slightly if you microwave them too long.
I logged the data of a few re-activations to try to find the optimal batch size, here's a sample:
After I'm happy with the weight loss of the reactivated sieves, I pour them into another, larger, Pyrex pan sitting in a preheated oven (200-250F is fine) we're just trying to keep them from pulling in moisture while other activation batches are running. When all the batches are done, I just turn off the oven, and let it cool to ~100F or less. This is to prevent the hot sieves from melting the bottom of the container I keep them and filament in.
The container -
For years I've been using 21 cup Rubbermaid dry food storage containers. They've changed designs a bit over the years, but THIS is the current incarnation. Currently $10. I've recently also purchased cheaper containers that show a lot potential. They're a little narrower, so not all filament spools will fit inside them.
I pour in 100-250g of molecular sieves into the bottom of the container, or if you prefer neater and more containment of the sieves, you can put them in a small mesh bag. Then put a spool roller on top of them, or the bag somewhere inside the container or in the center of the spool. There are many spool roller designs available, but this one is the fastest to print that still has a cross brace between the two sides, and uses cheap and common 608 skate bearings. I've recently encountered the cardboard-sided filament spools and instantly hated them. They don't always roll well (bent or dinged side) and can bind up in the dry box when feeding out, so I found printable rims to put on these spools, which completely solves that problem.
How do I know my filament is dry?
I have used the cheap battery powered meters, but I don't like to have to buy batteries. Also, I found something much, much cheaper, and infinitely reusable. There are many variants, but I use the Dry and Dry indicator cards. I tape them to the inside wall of the dry box so I can see what color they are at a glance. Normally all 6 circles are a nice rich blue color. I'm not too concerned when the 10% starts to change pink, but if the 20% starts to change at all, I reactivate the molecular sieves.
Lastly, I feed directly from these dry boxes to my printers through a PTFE tube. Don't use the 2.0mm ID 4.0mm ID that you'd use for your bowden tube between your extruder and hot end. Definitely don't use expensive Capricorn tube. That's unnecessary friction. Use either 2.5mm ID or 3mm ID PTFE or FEP tube with a 4.0mm OD. I bought the white PTFE 2.5mm version from west3D in Portland because they're nearby, but you can also find other options at Amazon and elsewhere.
I use the connector fittings that feed the tube through the fitting to inside the container. Do NOT use fittings that terminate the tube inside the fitting. The filament will not feed smoothly into the fitting (especially a bend at the end of a spool) and cause a filament jam and failed print, unless you have a filament movement sensor.
As diffusion goes, moisture will work its way up the tube if you don't seal it off when you're not printing from it. I've found that tape works well. I happen to have a roll of flash tape I use for composite vacuum bagging nearby, but that's most definitely overkill. You can probably be fine with cheaper plastic tape folded over the end of the tube, or print a TPU plug.
For longer term storage, I use reusable vacuum sealing bags and a small mesh bag with the sieves inside, and a cheap rechargeable vacuum pump intended for sous vide.
These bags from West3D are 12"x13" on the inside.
I've tried some sous-vide bags that claim to be 4L capacity and 10"x13" and these will NOT fit a standard 8" diameter spool inside. These bags on Amazon might be the same size as the West3D bags, but I haven't verified.
The pump I typically use is in the above picture. It was in a sous-vide bag kit I purchased in 2020 for about $22 on Amazon, but it's no longer available. The closest I can find now is nearly double that, but if you like to sous-vide, then this might still be a good deal.
I've used this pump on a bag with a Blue Raven in the center of a measuring cup, and indicated an altitude of 20.6kft. It slowly "descended" and stabilized around 16kft.
There are blower/impeller style plug in pumps out there, but I can't recommend them for pulling a vacuum on these bags.
In the end, you can end up with something that looks like this, and never worry about having any moisture in your filament again.
The above Amazon links are affiliate links, so if that's an issue, then I can replace them with non-affiliate links. So, I might get a percentage of Amazon's profits if you end up purchasing what I've linked to. Your price will be the same either way. Seeing how the post above this one is to a YouTube video with Amazon affiliate links, looks like this is OK.
My secret weapon against moisture - 3A molecular sieves.
3A molecular sieves are the strongest desiccant I can readily find, and they're thirsty down to 0%RH with excellent retention, unlike Silica gel which wimps out around 15%. Using molecular sieves, I don't bother to heat my filament to drive off the moisture except for when I'm in a hurry or like in the case of a spool of ABS that was sitting in my shop for 3 years. (and then it's just an hour or two sitting in the bag (see below) on the heated bed at 80c.)
Here are 3A Molecular Sieves at Amazon, the first result is what I've most recently purchased, and that was in 2021, so they last a long long time.
New sieves should arrive activated (dried), but they're incredibly thirsty and will fill up and eventually lose effectiveness. To reactivate the molecular sieves, I place 100g of them spread out on the bottom of a 8x8 Pyrex dish, in the microwave in 3 minute cycles until the weight (of ones that no longer dry below 20%RH - not fully saturated) decreases by 10% or greater. Your Microwave May Vary. Usually this is done in 3 cycles, or about 10 minutes including the time to weigh them. Why the intervals? These guys get EXTREMELY hot. They can even glow, and leave divots in the surface of the Pyrex from melting the glass slightly if you microwave them too long.
I logged the data of a few re-activations to try to find the optimal batch size, here's a sample:
After I'm happy with the weight loss of the reactivated sieves, I pour them into another, larger, Pyrex pan sitting in a preheated oven (200-250F is fine) we're just trying to keep them from pulling in moisture while other activation batches are running. When all the batches are done, I just turn off the oven, and let it cool to ~100F or less. This is to prevent the hot sieves from melting the bottom of the container I keep them and filament in.
The container -
For years I've been using 21 cup Rubbermaid dry food storage containers. They've changed designs a bit over the years, but THIS is the current incarnation. Currently $10. I've recently also purchased cheaper containers that show a lot potential. They're a little narrower, so not all filament spools will fit inside them.
I pour in 100-250g of molecular sieves into the bottom of the container, or if you prefer neater and more containment of the sieves, you can put them in a small mesh bag. Then put a spool roller on top of them, or the bag somewhere inside the container or in the center of the spool. There are many spool roller designs available, but this one is the fastest to print that still has a cross brace between the two sides, and uses cheap and common 608 skate bearings. I've recently encountered the cardboard-sided filament spools and instantly hated them. They don't always roll well (bent or dinged side) and can bind up in the dry box when feeding out, so I found printable rims to put on these spools, which completely solves that problem.
How do I know my filament is dry?
I have used the cheap battery powered meters, but I don't like to have to buy batteries. Also, I found something much, much cheaper, and infinitely reusable. There are many variants, but I use the Dry and Dry indicator cards. I tape them to the inside wall of the dry box so I can see what color they are at a glance. Normally all 6 circles are a nice rich blue color. I'm not too concerned when the 10% starts to change pink, but if the 20% starts to change at all, I reactivate the molecular sieves.
Lastly, I feed directly from these dry boxes to my printers through a PTFE tube. Don't use the 2.0mm ID 4.0mm ID that you'd use for your bowden tube between your extruder and hot end. Definitely don't use expensive Capricorn tube. That's unnecessary friction. Use either 2.5mm ID or 3mm ID PTFE or FEP tube with a 4.0mm OD. I bought the white PTFE 2.5mm version from west3D in Portland because they're nearby, but you can also find other options at Amazon and elsewhere.
I use the connector fittings that feed the tube through the fitting to inside the container. Do NOT use fittings that terminate the tube inside the fitting. The filament will not feed smoothly into the fitting (especially a bend at the end of a spool) and cause a filament jam and failed print, unless you have a filament movement sensor.
As diffusion goes, moisture will work its way up the tube if you don't seal it off when you're not printing from it. I've found that tape works well. I happen to have a roll of flash tape I use for composite vacuum bagging nearby, but that's most definitely overkill. You can probably be fine with cheaper plastic tape folded over the end of the tube, or print a TPU plug.
For longer term storage, I use reusable vacuum sealing bags and a small mesh bag with the sieves inside, and a cheap rechargeable vacuum pump intended for sous vide.
These bags from West3D are 12"x13" on the inside.
I've tried some sous-vide bags that claim to be 4L capacity and 10"x13" and these will NOT fit a standard 8" diameter spool inside. These bags on Amazon might be the same size as the West3D bags, but I haven't verified.
The pump I typically use is in the above picture. It was in a sous-vide bag kit I purchased in 2020 for about $22 on Amazon, but it's no longer available. The closest I can find now is nearly double that, but if you like to sous-vide, then this might still be a good deal.
I've used this pump on a bag with a Blue Raven in the center of a measuring cup, and indicated an altitude of 20.6kft. It slowly "descended" and stabilized around 16kft.
There are blower/impeller style plug in pumps out there, but I can't recommend them for pulling a vacuum on these bags.
In the end, you can end up with something that looks like this, and never worry about having any moisture in your filament again.
The above Amazon links are affiliate links, so if that's an issue, then I can replace them with non-affiliate links. So, I might get a percentage of Amazon's profits if you end up purchasing what I've linked to. Your price will be the same either way. Seeing how the post above this one is to a YouTube video with Amazon affiliate links, looks like this is OK.
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I've also used the large storage boxes. These ones in fact, which have a foam seal around the edge.
The seal is not air-tight, and moisture will ingress, requiring you to recharge your dessicant much more frequently than a vacuum bag and dessicant on each spool. I do keep my bagged spools in these containers though.
For even larger spools, to feed my Prusa XL, I'm looking into o-ring gasketed ammo boxes, that will hold an air-tight seal. I haven't built one yet, but I can't see why it won't work. Compromise is you can't see the spool (and amount of filament) with the container closed, and they're more expensive.
I own several drying boxes, including a dedicated camera/electronics cabinet I bought off craigslist.
The two I like the most haven't been mentioned
First is the Printrdry - https://www.printdry.com/
Handles multiple spools, heats up to 85C, can be expanded to handle 5kg spools and has holes around the entire device to connect a ptfe lead. I backed the original one on Kickstarter 5 years ago which still works great, and have versions 2 and 3. I use them exclusively for large spools, but very glad I have them. They also sell accessories for long-term storage that are quite nice.
Second is the new Sunlu S4 dryer - https://www.sunlu.com/products/sunlu-filadryer-s4
I own two of these and am quite happy with them. I like the auto-control by humidity vs. setting time and/or temp like most others. Has multiple egress points for filament, and can manage 4 rolls at the same time. The build quality feels a little flimsy, but I haven't had any issues yet. The only issue for me is temp only goes up to 70C which isn't quite enough for Nylon or PC, but I have other dryers for that.
Finally, I'd put a recommendation in for a different desiccant. I started, like most people with Silica gel, and still like it for certain uses like a Bambu AMS, especially because the new ones change color to indicate saturation. I've also used molecular sieves - especially for large rolls that don't fit in traditional containers, but I haven't had a lot of luck with 3A or larger mesh, which needed to be finer.
For the last few years, I've switched to activated alumina. Seems to suck the humidity out of the air better than anything else I've used. You can reactivate it in the oven, and throw it
The two I like the most haven't been mentioned
First is the Printrdry - https://www.printdry.com/
Handles multiple spools, heats up to 85C, can be expanded to handle 5kg spools and has holes around the entire device to connect a ptfe lead. I backed the original one on Kickstarter 5 years ago which still works great, and have versions 2 and 3. I use them exclusively for large spools, but very glad I have them. They also sell accessories for long-term storage that are quite nice.
Second is the new Sunlu S4 dryer - https://www.sunlu.com/products/sunlu-filadryer-s4
I own two of these and am quite happy with them. I like the auto-control by humidity vs. setting time and/or temp like most others. Has multiple egress points for filament, and can manage 4 rolls at the same time. The build quality feels a little flimsy, but I haven't had any issues yet. The only issue for me is temp only goes up to 70C which isn't quite enough for Nylon or PC, but I have other dryers for that.
Finally, I'd put a recommendation in for a different desiccant. I started, like most people with Silica gel, and still like it for certain uses like a Bambu AMS, especially because the new ones change color to indicate saturation. I've also used molecular sieves - especially for large rolls that don't fit in traditional containers, but I haven't had a lot of luck with 3A or larger mesh, which needed to be finer.
For the last few years, I've switched to activated alumina. Seems to suck the humidity out of the air better than anything else I've used. You can reactivate it in the oven, and throw it
I own both. I Like the Print dry also.
I have one of these. When not using for food, works great for drying filament.
https://www.cabelas.com/shop/en/cabelas-deluxe-10-tray-dehydrator
https://www.cabelas.com/shop/en/cabelas-deluxe-10-tray-dehydrator
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