@BambuBanker You tell me. Does Bambu filament have that kind of notch? It’s been so long since I’ve used Bambu filament that I no longer even remember.
No doubt you could re-spool any filament from any vendor onto it, or perhaps construct an adapter. However, I was looking for an easy drop-in solution, not more problems or additional things to do.
Yep it does, all Bambu filament besides those sold on cardboard spools have them. They don’t use a bolt though, they just have a little plastic notch on the spool that fits into it.
Maybe a metal spool could accelerate the drying process, if only because it would help to better conduct the heat to the center and side of the filament on the spool. That would be an interesting A-B trial to run.
Visually confirmed: the Creality “hubless” spools claim Bambu compatibility and also demonstrate the required notch:
I’m not wild about the cardboard core though.
What kind of core would you prefer?
Preferably nothing at all. At least in the past, Sunlu was like that:
It came with 3 velcro straps that held the held the filament spools shape. I’d slide it onto a master spool, unhook the velcro straps, and voilà!
At least in my experience, cardboard of any kind usually arrives holding moisture, so it slows down the drying process. As already mentioned above, in the worst case it can shed onto the filament, effectively polluting it while also increasing the risk of a jam.
Looks as though prices have dropped since the time CNC Kitchen last covered this topic. Here is the unit used in the youtube short directly above:
That is pretty cool, thanks for sharing.
I remember heat being an additional source for helping to actually get the moisture out of the filament, but if you dry it before using it, that shouldn’t be an issue.
And if you have it on top of the printer (like shown in the video) you would get some residual heat from the printer and might even help dry the filament in the AMS.
Still a very interesting topic.
This guy finishes off his filament drying by putting it in a vacuum chamber:
For convenience, I set the time index to where he talks about it. We had talked about this approach also, but I don’t think anyone here actually tried it and reported on it. Unfortunately, he doesn’t cite any evidence, but just the belief that it helps. He puts it in for 12 hours.
Overall I think he does a far better job than most youtubes at overviewing the different aspects of filament drying, keeping it dry while storing, and keeping it dry while printing.
Possibly the best youtube overview of the drying topic yet:
Very well photographed!
Lots of detailed information in table format.
He points out that silica gel doesn’t work all that well at 50C and above.
With regards to PPS-CF filament, I found that raising the drying temperature by even 10C can make quite a dramatic difference in the amount of extracted moisture:
Consistent with the temperature findings published by My Tech Fun in one of his youtube videos.
I don’t think you’d need to go as far as Peltier’s just a section of copper tubing painted black and with a fan on. All you need is to get the air temp back to near room temp. Even this lower cooling rate will cause condensation to drop out of the air whilst being cooled… For example if you are heating to 70 degrees and have a Rh% of 60% coming out of the dryer. Cool this to 20degrees and the RH% will be near 480% which isn’t possible so about 1 milligram per litre of air would drop out. This is 1mg per litre not heading back in to your silica gel and decreasing with every litre passing through. I think this would improve the efficiency a lot as you are not injecting air at 40% RH in to the dryer and saving the silica gel a bit.
what does painting it black achieve?
If its worth doing it has got to look good 
Joking aside the colour can change the radiation levels so a matt black surface will allow more heat to escape the tube than say a shiny copper one would… and yet we all paint our radiator white gloss 
I get it now. You’re changing the emissivity
In principle cooling the air to the dew point could take some water out before feeding it into the desiccant to more fully dry, but an aquarium pump doesn’t really heat the air. It’s close to room temperature. Very low pressure above atmospheric. Painting the tubing black and putting a fan on it won’t do anything in my setup and paint actually adds some amount of insulation.
I got lucky with the air drying configuration. Water doesn’t come out of the filament that fast so low flows of dry air are fine. At the beginning of drying the water in my setup comes off faster than the dry air can sweep it out at that low flow so I don’t even run dry air during the first half of the dry. A door prop works better. But around the midway point, opening the lid and wafting in room air will stop reducing the humidity in the box. That’s when I add the air. Might not be precisely the right time but it makes my desiccant last about twice as long and the drying is faster since the door prop is more efficient at first when “lots” of water is coming off.
It’s gotten routine. I dry all my filament using this technique and have now for over a year. It has worked great. I don’t need to tune filament profiles. Prints look great. It’s to the point I don’t have any need to improve it further.
But that doesn’t mean it still can’t be improved. And it’s important to understand ambient humidity also matters. Not everyone needs to do all this stuff. But there’s just not enough pressure or heat in my setup to make cooling the air headed into desiccant have any effect. It’s already essentially at room temperature.
