I printed those, they didn’t come with the AMS. JonRaymond gave a link to other models, and the exact ones I printed are these from eds_3d_shop. (Which ofcourse work just as well with the bigger diameter of the activated alumina perls).
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Well this was a rabbit-hole I didn’t expect to be so deep!
Wowzers! So much information to take in from this thread (and a lot of items added to my Amazon cart :P). Thanks to the folks posting their full racks of filament, makes me feel better about “only” having 3 totes full.
Definitely picking up some of the cardboard humidity sensors, and switching form color-change to clear silica desiccant now…
One idea I’ve been mussing about for ages is… is it possible to dry filament just using freezing temps (aka outdoors)? Our winters get down to bone-chilling temps… and “everything” you touch snaps from static due to the air being so dry. The biggest issue would be condensation build-up from transitioning from cold to warm environment…
Has anyone tried using a chest freezer for drying?!
It is totally possible to freeze-dry your filament outdoors in the tundra. All one needs is a continues wind to desiccate the material. Shouldn’t take more than a few weeks to dry. 
In all seriousness, it would help to understand how cold versus heat desiccation works. In the case of the tundra (characterized by permafrost, with ground that remains frozen year-round and very little precipitation as found in the arctic), items desiccate because ice sublimates—changing directly from solid to gas—rather than evaporates. Contrast this with heated desiccation, where water turns into steam, and one can quickly see how the laws of physics operate differently in these two conditions.
That’s a long way of saying, “You need heat to do it correctly”.
I went with the “big trunk” idea which doesn’t help the OP – but that was also 5 months ago, lol.
I wanted to avoid the cost and trouble of individual single spool solutions. I’m using the Sterilite 80 quart gasket bin, about $15. Side note: If you have a WalMart near, that’s the place to get one. Transporting these in a onesie-twosie manner takes up lots of space on a delivery truck, so Amazon is usually twice the price.
I purchased some PET sheet panels and 3d printed some L shaped pieces that screw into the sheet on one side and screw into the container on the other to create 3 sections to keep the spools from just sliding around everywhere. In the spaces not taken up by spools I have desiccants containers and attached a hygromneter to the top.
(Gotta love the south, opening the box long enough for the picture and 35% humidity
For unopened spools, I’m using a sterilite 105 gallon container which holds around 22-24 spools, more if they were all refill spools. This container is a perfect size fit to the “Amazon Basics 4-Shelf Adjustable, Heavy Duty Wide Storage Shelving Unit” Again, WalMart.
I’m new to this, starting storage with the 20 qt sterilite sealed totes. Printed some clips to better deal the long sides. Placed a hygrometer in a new empty totes, a long with one spool desiccant holder. RH was 51% initially.
Come down to 16% after a few hours.
Now I’m drying my PETG HF and PETG basic before placing in storage. Probably put a little more desiccant in each tote. Bought the totes at Walmart for just under 7.00
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What filament type works best for the side clips? I’ve printed clips in the past out of PETG, and all of them eventually broke. Not immediately. But eventually.
I’m just using PLA and beefed up the walls.
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Finally got a scale, actually it was the second scale I’d bought yesterday after returning the first scale that didn’t register .1 grams. Drying all my filament before they enter the storage tubs.
First up is my PETG HF
Before drying orange
After drying
Before drying green
After drying
Drying temps of the actual PETG HF were ~123°f which was pretty consistent between pointing my IR thermometer at the filament and the hygrometer that’s used commonly in storage and AMS units from Amazon.
I’ve had this old food hydrator for several years with no use. I cut the trays from the outer rings, holds two rolls at a time. Hygrometer registers 10% RH.
RH inside storage tubs seems to stay 16% with dried filament and two desiccant spool holders. Perhaps I need to use more desiccant in the tubs?
Current outside tub RH is 39%, will get upwards of 55% throughout the day.
I’ve printed quite a bit with the PETG HF and thought it was pretty good straight out of the package, but after drying I see a definite improvement.
The biggest improvement I saw was some PETG Basic I just received. Out of the box, I printed one half of a spool, noticed some stringing, pulling away on the inner circumference of the spool. Dried in hydrator ~12 hours at the ~123°, then printed second half. Huge difference in print quality. This was a roll of PETG basic white from Bambu.
I’ve just been doing two rolls at a time for approximately 12 hours, two during the day, two at night.
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That’s very cool and great results! The scale really shows how well it’s working too as well as the print report.
@CRracer712 Nice write-up!
I do have one suggestion, though: take a few more weight measurements during the drying process, and record both the weights and the timestamps. This will give you an indication as to whether the drying process is asymptoting, or whether you have more to go. Objectively speaking, it’s the only way I can think of where you will ever know for sure. 12 hours may sound like a long time, but it’s an artificial number.
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Yeah, weigh the spools periodically until a constant weigh is reached.
CRracer712 May I suggest you using this clips with your Bambu Labs spools? They are compatible whit the AMS. I designed for my own use but they have reach some attention:
Those clips look nice and sturdy, but I would miss being able to just click the filament in from the side as well as slide it in from the end. (BTW, I like your multiboard implementation).
I use this model as it allows both ways of clipping the filament:
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One thing, though - be quick about it and close the dryer back up while weighing. Depending on ambient relative humidity, you can add a fair amount of water to the dryer chamber and even the filament itself while it’s outside the chamber. Especially when you are nearing the end of the dry, that water can set you back an hour or more. As the weight change slows down, it’s probably better to spread out the weighings, too.
The added water in the chamber sticks out like a sore thumb on the chamber hygrometer. Leave the spool on a scale with enough resolution and you can watch it gaining weight from water it’s pulling out of the air. As filament gets dryer, it “wants” water more. When you’re barely getting water to come off the filament, a little added water can blow all gains away.
How long does it take before you can see it going up?
My scale has a resolution of 0.01g, but I so far haven’t noticed it. I do try to be fast though. Also, the “settle” time can be tweaked so as not to wait so long for settling, and maybe that interfers with showing the effect you described.
For the reason you gave, plus sheer convenience, I do think it would be cool to automatically monitor the weight of the filament spool without having to remove it from the dryer, like that one filament dryer I posted about not all that long ago which could do that:
In theory such a dryer could even be programmed to dry until there’s no further change and then shut down. Plus, maybe it could also provide a fairly accurate “time remaining”.
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I see the weight start increasing right away. I zero the scale, set the spool on, and then have to get a weight quick as it is getting heavier at maybe 0.01g every 5-6 seconds. Ambient humidity here is running around 45-60%. Today more like 45%. I’ll get a rate next time I weigh a spool.
Added… Olias said that typical scales will get offsets if weights sit on them but I’m sure there are ways to get around that but like everything, it might not be cheap. Haven’t looked into it though and I’m paraphrasing Olias.
But the more time I’ve gotten with my own rig now, I’m starting to move the other way - less complexity which obviously may not be appropriate for other filaments or how others maintain their filaments.
What I mean is I’m seeing great results just putting a spool in and letting the dryer run to a particular chamber humidity (19% for PLA at 53C) and calling it good. I’m weighing before and after but all it’s doing now is confirming that water was indeed lost. I’m only still weighing to characterize how things go as the desiccant loads up but am thinking it’s not actually necessary.
I know you are looking at other filaments that need more drying, though, and I definitely understand it gets tougher at the boundaries. My experience isn’t so useful. But for PLA… 
@NeverDie - I need to correct this. I had a nearly full spool of BL gold basic PLA in the dryer that lost 1.9g to an RH of 19%. Ambient humidity was 43% IIRC. I took it out, weighed it, and then watched for the weight to start increasing and it did not for the time I had it there waiting for the weight to change - about 30 seconds was all I gave it. It was pretty centered on the scale, no air currents, etc. I have no explanation. I did see the numbers increasing on the scale before but with not seeing that this spool either my interpretation was wrong or maybe something else but the advice to be especially quick may be wrong.
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I’ve got a couple rolls of PLA going now, after 3 hours, no change in weight.
What’s your ambient humidity and humidity in the chamber?
Maybe heat from the filament affected it, although I have no explanation as to why that would be true of only one of the two spools you observed. You could put a spacer or insulation between your heated spool and the scale, though, and if you never see a recurrence, maybe it was the heat.
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It’s showing 10% in the hydrator, one of the photos I believe shows the hygrometer laying in bottom of dehydrator.
Those two rolls of PLA did lose a little weight overnight. No change after 4 hours, but a little change this morning after 12 hours at ~105°
Just FYI, the filament clips not shown in the after photos are in the bowl that the filament is resting on.
As for ambient humidity, at what minute of what hour/day/month do you want🤣 it’s all over the place here.