Finally got an AMS HT to compliment my full size AMS, and I got to say I’m pretty disappointed.
Brand new desiccant, the thing can barely hold at 20% with or without filament. I just ran it at 80 c for a couple hours empty to dry it out, as soon as it cooled off i’m at 21% again.
Feels like this thing has a hole it in somewhere. It’s slightly better than my sunlu s2, and my creality pi.
My AMS holds firm maxing out the minimum of my hygrometer at 10% all times. I was expecting the same performance but maybe even better considering there is much less room for air to desiccant in the chamber.
It’s not just you. Mine also eventually equalizes with ambient humidity, or close to it if there’s some desiccant in there. AMS 2 next to it stays much dryer, not to mention my own roller boxes in sealed Rubbermaid containers (10% on those same hygros). I’ve tried taping the vent holes and removing the PTFE tube, but neither helps. Pretty sure it’s the lid overall. The same issue is subject of, or mentioned in, multiple threads here, most recently: AMS HT - How to keep it dry
Heating it isn’t really going to remove moisture, if anything it will attract more moisture into the unit since warm air can hold more of it (so the relative humidity appears to be lower, but there can actually be more physical moisture in the air than at lower temperatures). Then as it cools that extra moisture it still partially trapped inside. What heating to 80°+ might do is dry any silica desiccant in there a little bit, which would restore some of its effectiveness, eventually returning the unit back to its original “equilibrium” humidity level.
Ah alas… I wouldn’t have even bought the thing. Reviewers don’t go over this at all. Why would the full size unit work so much better than a smaller one? Kinda weird. It gets wildly humid here in the summertime. Now it only feels useful as a 5th ams slot… but one where I can’t just leave the darn filament in there and not worry
Indeed, I’m between “happy with” and “impressed by” my other BL hardware, but feel the HT was a bit of a waste. Didn’t work out for me for drying either. And yea now that the humid season is starting up here, not going to be great for storage. At least not w/out going through (drying) a bunch of desiccant. Others here have said they work fine for them, so maybe there’s manufacturing discrepancies or what-have-you… Mine works nicely as an actual AMS, so that’s something…
After drying done humidity will bounce around a bit and then should stabilize to the true internal RH as it cools.
The gasket around the lid can fight with the lip on the lid and you need to make sure it’s seated all around a few times when it’s new
Ok a third thing. The air valves open and close while drying and they have failed for some. When it’s off look and see they are closed bottom and back. I think orange is closed. It’s on the wiki
I have several and they hold 6-8% fine in a 55% room once the filament is nice and dry. But I have had a pinched gasket more than once not close lid good and it crept back up to near 30% very fast. I don’t even use the dessicant holders in the AMS Hat anymore just one indie the spool.
I’m also pretty disappointed in mine. I’m back to storing my filament in my other methods after drying.
The little desiccant holder spot in the back is pretty much a waste of time anyway. I’ve tried a center spool desiccant box and even added some of those curved boxes around the outer edge of the spool for storage but the RH still crept up pretty quickly.
Except when actually drying a roll of filament I just use the HT as an “automatic external spool”.
It’s 55% humidity in the room (Basement) right now and 84% outside for the last week although its dropping today. Thats not desert dry. There may be other factors involved for some, but I have not had any issues with keeping filament dry in cereal boxes, 3D Printed spool holders or AMS 2s or AMS HTs.
If you are looking for the HT to be a long term storage then the little packets are probably not going to cut it. My ambient humidity is 55-57% and after drying in the HT the filament hits about 8 and settles in around 11%.
The difference is I added a larger desiccant container that keeps stuff on both sides of the filament. Since I added this, no other issues.
to me the bead bag seems to hold more desiccant than the bin I found on makerworld.
Did want to point something else. Dried the box out and through a hygrometer in there… screen says 21% hygrometer is remaining bottomed out at 10%… I think like someone said again that screen is just wrong. WHY do manufacturers keep putting the sensors in stupid places? Same with my sunlu and creality dryer.
I stuck a couple hygros in mine also, since posting here. One in the front, one in back near the desiccant storage (the stock BL packets in there, still mostly orange). Granted these hygros aren’t really accurate at low levels, but they did read within 1% of each other @ ~35%, before I put them in. After ~24 hours in the HT I get a ~10% difference between the two, the one in the back reading lower (ambient is 36%, front hygro reads 30%, rear reads 20%). That desiccant stuff really works I guess…
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Sure, one could dry out just about anything with enough desiccant. But the stuff isn’t infinite… even if drying it vs. replacing, that’s still time and energy used. I use cans of alumina mounted in the spools… when one is in the HT, that pulls down/maintains the humidity on its own (plus whatever the filament absorbs… lol). When the HT is unused, I can easily load it up with a couple desiccant cans to keep it bone dry, or several to fairly quickly dry it out before use. Just have to bake the stuff more often… not a huge deal really, but adds to the maintenance.
Just wish it sealed better in the first place, if that’s even possible. Wonder if a thicker gasket or tighter latch would help, but probably not that “simple.”
I am sure they are not lying, but they don’t say what they qualify as their concept of “Air tight filament storage” so I presume it’s different than yours.
I don’t really understand how mine is acting. After a dry and without opening it crept up to nearly room RH over the course of a few days. I printed one of the dryboxes suggested above (there was already a spool weight desiccant box and the little tiny one that goes under the rear roller) and put it in, the RH dropped maybe 5 or 6 per cent over the next few hours. Out of frustration I threw in one of the little round hygrometers and the reading on it dropped from room RH (mid-thirties) to 10% within about thirty minutes and has stayed there for several hours.
I know the round hygrometers are not the most accurate things but seem ok for spotting general trends. I’m wondering if the on-board AMS sensor isn’t reading RH in the actual filament chamber. Perhaps it is on an internal board and is seeing air leaking into the case from outside. There are cracks and gaps around the various connectors on the back and the seam around the entire bottom edge. Somehow it doesn’t seem to me the leakage is around the lid gasket.
I have 5 of them with PC/PA6/ASA/ABS filaments in them right now, haven’t dried in a few weeks and only have a spool desiccant inside each spool. 6%, 11%, 13%, 8%, 11% all around 25C. I log them in HA and going back you can see where the humidity drops down to 5 or 6 when drying when it stops it shoots up as the temp drops them stabilizes back normal. It takes a week to go up 1% from what I am seeing in the historical data.
The room is between 48% and 60% and the dehumidifier only runs if it gets above 60%.
If you don’t dry it all the way, it will creep back up though. I had to dry a roll of opened PETG Basic twice at 65/18 before it would stop going back up.
