Has anyone had issues with the Blue petg hf that was shipped just before Christmas? Mine was full of moisture. Dried it at 150f for 8hrs. That was no help. So dried it at 150f for 16hrs. It got about 80% of the moisture out. I have again dried it 2 more times for 20hrs each time. And now it is back in there for another 20 hr run. I have never had a roll of filament like this. I have used 100’s.
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I don’t understand the problem.
What color would you expect filament that’s full of water to be? Orange?
(Sorry, bad joke, don’t get mad. But I actually don’t understand what you’re pointing out in the photos. I don’t doubt the water issue.)
I have the a spool of dark grey and also got very unclean sides. Also tried to dry it very long, without any improvement. Printed a temperature tower (with OrcaSlicer) and changed the printing temp to 230C (as it came out best on the tower). Also changed the retraction length to 0.2mm (as I found this post). That fixed the issue for me.
Hope this helps!
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I will run a temp tower again. Mine ran best at 240 (temptower) after the second dry cycle. It has little air bubbles in the lines. Little pot holes. I have started a ticket to see if they have any insight.
Bottom pic on the right you can see tiny holes in the lines. Caused by water getting heated above the boiling point in the filament. It has to come out when it is vaporized.
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Yeah, I think I see it now.
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I also had that with a batch of black. Earlier batch printed perfect after a few hours of drying. Newer one, even after 24 hours at 65 deg c printed with zits. It was getting better and better and the very outside of the roll was dry enough, but it was a challenge.
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From the perspective of a 3D printing enthusiast, should this be acceptable as a product? I’ve been printing with Esun PETG because it’s printable straight out of the box without any special tuning. I made the mistake of buying the Bambu PETG HF product which I have instantly regretted as it is a steep learning curve for a 3D printing part timer.
All Bambu PETG-HF colors should be dried before use.
Weigh it, dry it, quit drying when it stops losing weight.
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I have a refill of blue from around the same time. I have not experienced the trouble the OP had.
I did however have a Green refill tangle on me.
Out of 6 refills I had, that was the only one I had an issue with. I did just submit a ticket a few minutes ago so, I will wait and see what support has to say.
Seems the moisture issue can be hit or miss. I have seen some posts where some have just printed out of the box without drying and had no problems and I have seen other posts similar to the OP.
I bought it to see if it was any better than the Elegoo Rapid PETG I’ve been using. I dont think it is BUT the BL prints with a matte finish, which looks good. The Elegoo prints with a shinier finish IME. I guess I could turn the temp down on the Elegoo. Thats for another day. Honestly, I like them both.
Matt
One more… I got a light grey PETG HF - dried it for 48 hours at 65 - extra long just to be sure, rotating every 6 hours. I bought a “laser” thermometer gun to verify the spool is getting to temp. Then I hooked up my filament dryer to the printer and printed from it while drying. It was a 6 hour print. First half printed really well and super clean, second half - full of zits. Similar experience with the black spools from earlier.
These rolls are impossible to dry. The only way I can think of getting them to work for a long print is to respool what you need but loosely - so that the air can get through easily, then dry that before printing.
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Yeah the fact that air can’t even reach the filament inside the spool occurred to me early on too.
Maybe we need @MZip to engineer us an uber drying contraption which gradually respools the filament while it’s being dried so every bit gets hit with some hot, dry air. 
If you search the forums there’s a giant thread he started where he’s forcing dryer-than-ambient air into a dryer using an aquarium pump. Maybe that would help. I might try doing it with the S4 I have, if I get to a point where I feel I need it. In the middle of a nice dry-ish winter right now.
Found it:
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How about a double-wide spool that fits into an S4 or similar two-spool wide dryer, wound loose, and then when it’s done you wind it back up onto a regular spool? I think we’d need a special system which unwinds from a regular spool to the double-wide and then can cleanly wind filament back onto the regular spool later on.
This would be some overkill and over-engineering I could get behind.
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Unfortunately, one of the factors that slows things down is volume in the filament dryer, though. In a multi-bay dryer you would want to either have spools of filament in the locations or closed cylinders the same size as filament spools to exclude dead air space.
I use a low flow of air from an aquarium pump to purge with dry air. For about the first 3 hours or so of the dry, humidity spikes as water comes off faster than the purge removes it. But after that humidity starts coming down which means the water is being purged out faster than it can come off the spool of filament. The aquarium pump flow rate is a good match for my Sunlu S2 and the aquarium pump I used with about 8-10 hour drying times.
Put 4 spools in an S4 and water will be coming off about 4x faster. You may need to scale the pump up to keep the same kind of balance. It only took two aquarium pumps to find one with adequate volume but you would probably need more flow to see the same kind of crossover. Efficiency should be the same if you increase flow and you should see the same kind of drying results.
The silica gel charge I use is 800g and I stopped the first charge at 27 spools dried IIRC. I’m still running the second charge and it’s just been going and going. It’s getting quite dark but still dries filament like a champ. Output humidity reported by two hygrometers has both still pegged at 10% when it’s running. Pump 4x the air through and you could see breakthrough effects (higher exit air humidity) if using the same size column, though.
Anyway, I can assure you dry air purging a filament dryer does wonders for filament moisture. It’s very repeatable, you can bet on it, and prints are really and truly better because of it. I started seeing water effects so did the deep dive. I haven’t seen water effects since. I dry all my spools and keep them in poly boxes with hygrometers and a sachet of fresh silica gel beads. All of those still read 10% RH.
Here’s some PETG HF I printed and you can see for yourself. It is a patch for an ice maker where I started printing from dried filament but it needed a spool swap partway through. The 2nd spool that had come straight from the shipping bag into the dryer but wasn’t fully dried when it needed to be put in service - had about 5 hours drying time on it - but you can still see easy where the swap happened by the change in print quality. Lower part of the print dried using dry air. Upper part only partially dried (but using dry air). The filament change is above and to the right of the middle hole on the left with the string bit sticking out. Unfortunately there isn’t an example using the filament fresh from the shipping bag but it would be worse than the partially-dried spool.
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Update on this - the filament dryer pre-drying the filament was fine but the filament dryer I was printing from was faulty and wasn’t getting up to temp (according to my temp gun only about 50 deg C - I should’ve checked this earlier, I only measured one dryer), I fixed it, set it to 80 deg C (the spool got to about 70 deg C) and it printed without zits.
This STILL does mean I can’t do long prints from the AMS unless I go through some convoluted drying-rewinding-drying-rewinding-drying procedure for every spool.
I did however get a couple of black clumps which came loose on the perimeter walls, leaving big gashes, ruining my print. I used an infill pattern that doesn’t cross over itself too. Their marketing claim “It effectively addresses common issues such as oozing and clumping associated with regular PETG” I don’t find completely true. I think setting their default flowrate to 0.95 is a cheat for reducing clumping but this left gaps on the top surface for me. Tuning this to 0.98 to have no gaps on top lead to clumps.
This is annoying but I think I need to just use the “Top surface flow ratio” setting to seal the top and accept under-extruding everywhere else (and have separate process presets for PETG HF, and accept looser fits between parts designed for proper extrusion rates, etc etc)
Do you think this will be popular? Haha, a motor, a run-out sensor and a polymaker dryer thingy would work but man this is a huge side quest
I was mostly joking because it’d be really hard, and yes it would be a massive side quest , but if that isn’t the holy-grail of dryness I don’t know what else would be.
If somebody could design something like that to work in a reasonable amount of space, at a reasonable cost and convenience… and it produces results, sure. 
Honestly I guess this would be overkill… most of the time.
I’m actually tempted haha. The monetary/points payout for the effort would be quite low because it’s such a niche tool but it would be extremely satisfying to create the ultimate filament dryer!
On second thought, perhaps it’s better to just dry the AMS - and there are already several projects for that.
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There’s two things to consider that slow drying time for filament. One is purging the water out of the dryer to keep the humidity down. The other is just how long it takes water to work its way out of the filament.
Those using food dehydrators get lots of air flow to move liberated water out but if they don’t dry long enough they still get water effects. Some of the slowness is water getting out of the wraps but some and maybe a lot of that time is water leaving the filament.
It’s been a while but IIRC the guy who did the tin can filament dryer said his system would have worked better had he made his can heater longer. I think that was because of the time it took for water to work its way out of the filament.
I guess the point is it’s probably tough to really speed the process up too much.
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I think we are all seeing the same thing. The water will come out, but it takes days. I have just left mine in the dehydrator. Im guessing it has 200 -300 hrs dry time at this point. Its cold in the shop so the heat is welcomed lol. I can not use it unless it comes fresh from a 48 hr dry session. And even then it sometimes has bubbles that appear. I have another roll coming in a day or two.
I think a spooler with a drying chamber would be the trick. I will think about how to make something happen. This was by far the worst roll I have ever had.
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