Mine already has a fan whine unfortunately, but if I was to open it, I’d swap for a Noctua if possible and they also have a voltage drop resistor that slows them down and quietens them in non speed controlled situations.
I had wondered how hard it would be to make a good filament dryer but apparently it’s not so easy for a manufacturer.
How does that Creality vent? I am surprised there aren’t little butterfly vents that are user adjustable. Noting like that on the S2.
These suppliers of bags are just middlemen wrapping cardboard around stuff they buy in bulk from the cheapest vendor. Any one of us daring enough to deal with Chinese Supply chain could get in that business within a few week and be shipping from an Amazon warehouse while never having touch the physical product. Put simply, they just don’t care.
Oddly enough, I was never interested enough to do an actual teardown since I usually take everything I buy apart once just to see what I truly bought, practice I engaged in since I was 8 years old. However, from the brief investigation, their design does a small amount of external exchange out the bottom of the drier, I can’t yet find which direction the flow goes just yet.
I opened my S2 up and was checking out the guts. There’s no vent and if the lid is closed, it’s only the two filament ports for water vapor to escape unless you prop the lid open.
But the part that has the legs screws on and has a small cheap squirrel cage blower attached. The blower ports to where it blows air up the back side of the dryer chamber.
What I’m thinking now is I’m going to keep the S2 but modify it by replacing that squirrel cage with a much quieter Noctua pancake blowing up and drill a small hole in the center of that base where the fan draws up a little outside air with recirculating the inside air. I’m pretty sure there’s room for a thin duct to duplicate the squirrel cage output path.
I was looking at a number of other dryers and the only one I can find with any air exchange to get the water out is some clunky $300 one. I’m pretty sure these need to exchange a little air and am really surprised the popular ones don’t.
Worst case is I break it. 
The Easdry fan pulls in air, blowing over a 45W heater in the spool support. Warm air has to pass around the spool to exit out the back:
Typically about $55, I caught an Eibos sale on Amazon last November, $43.
Nice! Will look at Eibos. So weird so many others didn’t include air exchange. Thanks!
I’ve got my path forward and just need to order a 24V fan to make this work - and I think it will be relatively easy. The two images with fans are the bottom of the dryer. The bare plastic piece with the two bosses circled are the feet and current fan mount. The black fan is the stock 24V squirrel cage (noisy) fan. The tan fan is Noctua is just to test fit against the squirrel cage fan. Not the right voltage though and it’s also sitting on top of the blower fan. They are almost the same thickness so if it was 24V, could even just drill a hole below it in the base and wire it in place of the blower.
I suspect they used the squirrel cage fan to be able to direct its air and not be blowing directly on the back of the heating element but don’t know for sure. I’m also not sure that matters though the temperature sensor (not shown) is fairly close by.
The mounting holes line up pretty close (close enough) with a standard pancake fan and the clearance in the hole up to the dryer body definitely fits. There even is a way for air to get below the fan through that duct-like area to the right of the fans in the fan hole.
While I might be able to just use the existing bottom piece and legs, I think I’m going to draw up and print a new base to allow a tube port for something bong/hookah-like and pull the fresh air through a container of desiccant to get more capacity than something that fits under the dryer.
It would hopefully be a continuous replacement of heated air carrying filament moisture with dry”ish” air being pulled through desiccant. Not too fast. Just fast enough to get rid of moisture near the same slow rate it comes off the filament. Too fast and you just waste dry air and needlessly use desiccant.
Hey, thanks for sharing your experience with the Sunlu S2 Filament Dryer! It’s really interesting to hear how much of a difference it’s making already. I’ve also been storing my filament with desiccant packs and thought that was enough, but it seems like the dryer is doing an even better job. I’m in a similar climate with low humidity, so it’s good to know that even in these conditions, a dryer can help. I’ll definitely consider getting one now.
Hey Meghan, I don’t know yet how well my modification will work but am printing parts now to test fit. The stock Sunlu S2 seems to need some way to exchange air so if you go that route, might at least look at the doo-dads that prop the lid open.
I’m hoping this mod is what it needs to be much better though. I’m going to try it with and without pulling dry(er) air through desiccant and see how it goes. Hoping this approach pulls a little air but not too much. I’m going to use a hose barb to attach tubing from a desiccant container. Might still change things but this is what I have so far… The curved piece replaces the current base and mounts the fan. The other part becomes a new base with the hose barb.
I really like the dryer. The only problems I have with it is the PTFE tube location for dryer printing and the lack of ventilation.
Since no one makes a dryer that is fit for the filaments that need them most (Nylon, PCs, and PETs) I considered making one. But in all honesty, I’ve never had to dry for more than 8 hours so I guess making something high temp is overkill.
As for the design you made or found, I’m having a hard time understanding how that’s going to work with the S2. I get you mentioned it replaces the base, but that appears to need other significant mods to make the lid fit. Are we talking about the same Sunlu S2 dryer?
Ah - it’s for the Sunlu S2. What’s confusing maybe is there is a door/plate on the bottom of the unit that has the four legs at the corners. Here’s a photo of the bottom of the S2 where the new plate will fit - if it fits. That’s the current blower fan tucked out of the way so I can test fit. It’s normally attached to the bottom plate I’m replacing.
The new base replaces the plate and legs to create an air tight void below the dryer housing. The fan will draw from the void to blow air up into the chamber. It will pull air down through the port next to the fan in the replacement plate and also in through a side port which is where the makeup/maybe drier air comes in. The stock setup also uses that port. The stock fan rides in that opening but there is a slightly narrower section to the right which is the stock port.
Still waiting on the 24V Noctua fan, some silicone tubing, and some other bits but I think this could work. It’s all hypothetical at this point, though.
I’ll post details once I can test.
I recommend this spool holder for the S2, it works great. You pull out the rollers and it fits right in.
I never ended up printing the PTFE Holder in the other link, I just run the Bambu PTFE from the Bambu 4-in-1 PTFE Adapter to one of the holes at the top. I feed it through the plastic tube already in the hole. I position the spool so the filament goes from underneath the spool than up into the top hole rather than feeding it over the top of the spool. The path seems less restrictive.
I’ve used it with TPU-HF a few times, I keep the heater on while using it.
That is one impressive mod, my friend. It fixes almost everything wrong with the S2’s base and fan. This is already a great improvement over the tippy design using those subpar nubs they call feet in the OEM package. However, just a thought for added stability: have you considered giving it wings on the sides so that it’s not as tippy? They could be optional, or if you’re really going all out, make a 3mm plate that is the exact size of the base and mount it using a Nyloc nut so that the wings can optionally pivot out 90 degrees.
I left off the innerds until I got the fan but there’s a separate plate that mounts the fan that also has a throttle to set the differential pressure between the drying chamber (higher) and the bottom chamber (lower). The fan blows up from the bottom chamber into the drying chamber. There’s an outside air throttle but the hole is sized to squeeze fit silicone tube that can draw from a container of desiccant for lower starting RH if that behaves how I hope it might. That will need a bit more draw than just pulling outside air but flows should be low anyway.
I think your idea about the bigger base is a good one. I could just add it to the existing base as all a single piece if that would be easier than outriggers - or maybe they need big outriggers? How big were you thinking? I have no experience with printing from the S2 but I bet they do get tugged on pretty hard especially with a full roll. Only thing is that will more or less block off one of the vents/filament holes but that may not matter.
Was also thinking how to test. Trying to test how well each configuration works with any repeatability would be tough with filament rolls. Testing would change them. So I’ve got some silica gel packets in a jar so they can all equilibrate. I won’t know how much water they start with but if two lose water the same way I can hopefully trust the others are at the same water content and the humidity curves in different configurations should be directly comparable and show if there is any benefit to this.
Anyway, here’s the fan plate with the throttle on it. The throttle has the four holes but I also have a blank one that would restrict more. Don’t know what will work best yet. I’ll also print clips for the tubing to be able to throttle and close the desiccant off entirely. Have a clear Nalgene water bottle and fresh/sealed indicating desiccant for the dry air test and to run with if it works. Way overengineered.
For the short time I had the S2, one of the things I noticed as a design defect was that with a full 1Kg spool, the entire device was very unstable. This was particularly true when I sat the device on the table next to the printer. The table I have my P1 set up on is deliberately light weight. My thinking is that if you jus assume that the center of mass is at the center of the spool and then imagine an triangle jutting out from the base - use construction lines in CAD - where those triangle tips meet the base would be how far the canards would go. So then the question is, would that imaginary triangle have a 30 angle or could you get away with a 45 or even steeper 60 angle. I would imagine that 30 degrees should be enough.
Sorry for the crude drawing but this is what I come up with in five minutes.
Or another view with a hypothetical base
I’ll work up a version of the base like that and include it if it even works. But that would be a really easy mod. Thanks!
For those adding a fan to your dryers, use as little a fan as you can find. The air renovation needed for the humidity to be expulsed is minimum. A bigger fan will move more air and will lower the temp or raise the power consumption.
For the fan, I highly recommend a 40mm PAPS one. PAPS is a very god fan maker and a 50mm one will be VERY silent in comparison with other fan makers.
Good points. I’m not familiar with PAPS fans, though. For this I’m using a 40mm x 40mm x 10mm Noctua fan which is also very quiet - much quieter than the OEM squirrel cage blower but any fan of the same size should fit. I made the mounting holes m3 and m4 so as long as other fans use the same mounting hole locations you should be covered.
(Edit - This design and the port already molded into the Sunlu S2 base will not accommodate a 50mm or larger fan. You can probably add a mount or duct to adapt it but I’m not going to do that. There isn’t a need and the Nuctua 40mm fan is probably overkill anyway.)
And agree on the overall fan/flow situation. Mostly what this will do is circulate air inside the chamber. It’s that circulation that will set up a small low pressure in the base which is what will draw in ambient outside air or “dry” air from a desiccant container. The small port cover swivel thing on the outside is intended to be used as a valve to limit the amount of outside air. If using dry air from a desiccant container, I’m making printable tubing clamps to limit that air flow.
In use the pressure differentials should be small. I only added the throttle on the fan plate to be able to make the pressure differential larger if needed. I think in practice it won’t be needed and the relative sizes of the fan hole and return air duct will create all the low pressure needed to bring in outside air. I’m stuck with that fan and return air port size since Sunlu built that ratio in their original design.
I’m trying to do this with the minimum modifications. No plastic cutting or drilling. Unfortunately the old fan has to be replaced (in part to end the high-pitched noise it makes) so a wire splice is needed, but that’s it. Everything else uses stock holes and ports in the Sunlu dryer.
I think the desiccant container will really help by supplying drier air than ambient outside air and help speed drying, but letting too much air flow through the system will just deplete the desiccant. Finding the proper flow rate will be important but that’s why I’m going to run some tests to validate performance and see how it works in different configurations.
The stock system would have brought in outside air with a draft if they would have added a port to the bottom feet plate under the stock fan. I almost went that way but wanted to have the desiccant option and more control over flows. There’s an interesting footprint under the stock fan that indicates they might have planned something else for the S2 but the final configuration only circulates air inside with no forced air replacement. They seem to rely on diffusion through small gaps and the filament holes but that’s slow.
