Just a short note to put this on other new folk’s radar…
After seeing a number of posts about print issues that could be due to “wet” filament that has absorbed too much water, and other discussions around dryers, I decided to try one - the Sunlu S2 (~$70).
I haven’t printed with any “dried” filament yet. It just arrived an hour ago. I turned it on and grabbed a roll of Bambu Basic orange PLA, put it in the dryer, and the humidity in the box started rising. It’s gone from 33%RH to 39%RH in just a bit over a half hour. It’s apparently working and showing that even storing filament in poly bags with desiccant packs and storing those in lidded plastic bins, also with desiccant, leaves the door open to at least some water absorption.
Don’t know how much water a 6%RH difference represents but it’s obviously some so this is good.
The S2 has a fan to circulate the air but not much in the way of allowing that moist air out. I’ve seen where others opened up a hole by the circulation fan and may look into doing that, but will also try opening the lid and just let the hot air out occasionally first.
Anyway, so far so good. It looks well built and the LCD display is large and easy to read. I don’t know how it compares to others - it’s my first dryer. I had thought I was treating my filament well and probably didn’t need a dryer. Now it’s obvious I’ve got some amount of removable water in at least some of my filament.
I also live in high desert where our relative humidity stays low most of the time. The weather service and thermometers are saying it’s 35%RH ambient. I wasn’t expecting to change out desiccant much or have much water in my filament, but I’ve gone through multiple desiccant packs in the AMS and now this.
Anyone with printing issues might consider a dryer. Even with low ambient humidity and keeping filament in poly bags with desiccant packs in tubs with desiccant, even though really no major print problems, kind of amazing the dryer is already driving water out.
You should see it drop to 18%-20% which is great.
I print ASA & TPU straight from the dryer, I’ll also do PETG & PLA if the print in longer then 3 hours.
Yes, print one of the many lid openers to let air in.
Reports like this are why I picked the Eibos Easdry over the Sunlu S2. It did not make sense to me to only heat the filament and not also remove the moisture from the enclosure. The Easdry blows the air out the side. I’ve never seen the humidistat show an increase in humidity while running.
I check for absorbed moisture by weighing the spool. The weight generally stops dropping once the humidistat reaches 10-15%.
The Easdry does have room for improvement. The lid and catch are awkward to use. The spool mount should have less friction for printing directly from the dryer. Spools with large holes (Sunlu) require adapters to print from the dryer, otherwise they sit on the bottom and cannot spin.
Edit - Ah. I wasn’t considering the different dryers. With forced air ventilation it makes sense you might not see an increase. Only thing about ventilation is it can be a double edged sword and also add water. But that’s true with any dryer like these. They will always be a compromise of sorts because ambient air has water.
Print the wedge to prop the door open a bit. One of the S2 biggest issues was humidity getting trapped inside. The first ones didn’t have a fan at all.
It will work for you, esp if you prop that door a bit.
The fluctuations in relative humidity that you observe are normal, especially when you open the lid to let in fresh air. Relative humidity is temperature dependent; when the temperature rises, the air can absorb more moisture, resulting in a temporary drop in relative humidity. If the temperature remains constant, the humidity will gradually increase again as the filament continues to release moisture.
You can only open the lid if the humidity stored in the room air (outside the dryer) is lower than inside the dryer. You could then carry out a shock ventilation (for example with one or two fans and air flaps) to transport the moisture to the outside with the warm air. The dryers certainly do not have a moisture separator. It may be possible to build a simpler one with a Peltier element, in which case you will need a container to collect the moisture.
It is important that the moisture does not remain in the appliance after the drying process as this could affect the effectiveness of the dryer over time.
For an effective long-term solution, it would be ideal if the dryer had a built-in moisture removal method to ensure that the filament remains dry even when stored in the dryer for long periods of time. It would be interesting to see if future models could incorporate such improvements.
By using the filament directly after drying, you minimise the risk of it absorbing moisture again. The continuous transition from drying to printing keeps the filament in optimal condition for the 3D printing process.
It is also advisable to consider the storage of the filament after printing. If you have excess filament that will not be used immediately, you should store it in an airtight container with moisture absorbers after drying to maintain quality for future prints.
I own an S4 and have additionally stored silica gel in the dryer. By using silica gel in the dryer, you may be able to improve and maintain the condition of the dried filament, especially if it is stored in the dryer for a while. However, it is important to regularly check the silica gel and replace or regenerate it (at significantly higher temperatures than are reached in the dryer) once it is saturated, to ensure its effectiveness. By using silica gel in the dryer, the moisture may be absorbed more efficiently, which leads to the dryer having to activate less frequently to reduce and maintain the air humidity.
Ultimately, the ideal setting depends on the ambient humidity, the type of filament, and the frequency of use. It might be useful to experiment with different settings to find the best balance between energy efficiency and filament quality.
Yeah, looks like the S2 has some limitations in an otherwise snazzy package. Just heating the filament doesn’t cut it if it stews in its own humidity. The two filament holes in the lid seem to be the only vents and diffusion of water out through them will be slow. Still looking into this. I suspect it’s going to need a hole or two added but I may just return it. I have found if I just let the lid down without pushing it down, I get a tiny gap.
But one thing without a doubt, my way of storing my filament does still allow some water. The only filament I’ve had trouble with has been the “good” Basic Black and drying in the AMS has been sufficient to get it printing properly. (The bad shiny Basic Black was so bad I just threw it away after harvesting the RFID tags.)
I think a dryer is important though. These printers ask a lot of the filament and I’ve seen the difference in print quality just from AMS drying.
There are two active fan mod on Printables that required performing surgery on the plastic lid. To be honest, whenever I see a mod this drastic, that to me is an indictment of the OEM who designed such a flawed product.
Note: He is using a 40mm fan. Assuming that he is spinning it at a standard RPM, those fans can become quite annoying with their high pitch whine. After using my Creality Drier for the past couple of months, that is a major gripe I have. Creality’s design vents the air to the outside using a small diameter fan and the noise really gets on one’s nerves.
All of these designs require that one modify the case and thus destroying any aesthetic design objective that Sunlu attempted to achieve.
In a word, these are “ugly,” even if they do remedy the design defect. Why did I spend all that money to fix bad engineering and turn what was supposed to be an eye-pleasing product that one wouldn’t mind seeing on their desk into a high school science project?
I’m using a Sovol Filament Dryer, 2kg (2 filament rolls), which works well with PLA/ABS/TPU/etc. Until now I had
no issues with it https://amzn.eu/d/09hjXdBv
I started out using those too. The issues with those is twofold, the moisture indicators that ship with those are counterfeit and are only non-reactive ink on paper. I complained to Amolen and their response was to send me an entire duplicate box containing the same set of counterfeit moisture indicator cards. While that’s a nice gesture it didn’t address the defective indicator cards. So I defected from that as a solution and ended up buying moisture indicator cards separately.
The second problem with those filament bags is that they are scamming our community. First, they are oversized for the purpose and as such are overcharging us for like-product, $1.20 bag vs $0.90. The non-savvy buyer would be duped into purchasing this solution in the belief that it was specially made for filament when all it is, is a vacuum food bag. They are also needlessly disproportionately long. Filaments come in a square box for a reason so why send a bag that is 12.6x16.7 inches? This makes no sense. There are other suppliers that do a better job but they still over-charge also as I found out.
Here’s a tip. You can buy perfectly proportioned bags(13.4x11.8") for a fraction of the price. Just search for the term “Sous Vide Bags”. They can be had for $0.90 per bag and unlike the purpose-made “filament Bag” they are the correct size without the unnecessary plastic that interferes with even stacking and storage.
Having said that, I see that one “Filament Bag” seller I purchased from recently who has now offered the correct size, by the obvious Chinese scam name of Youpai, is running a special which makes it more competitive since they include a pump. When I purchased the same product SKU, it was a completely different listing with bags only and no pump, which is why I call this a scam listing. Either way, it’s a good deal now, and anyone who needs new bags can grab this and make out well. Note: I paid $29 for the Amolen version a year ago, but since they sent me two after I complained about the counterfeit moisture cards, I guess I made out well. However, if you go by his everyday price, it’s a ripoff. Caveat emptor.
If you are looking for a simple wedge, I created this. Works fairly well to give humid air a way out while still allowing the heating element to reach its top end range.
If I keep the Sunlu, I’ll print that, Mike! Yours isn’t as tall doesn’t open as wide as the others I looked at. It shouldn’t need much air exchange since the water loss is pretty slow. Thanks!
That’s upsetting. Instead of printing counterfeit indicators, they should just ship without them instead of misleading. It’s obvious I know, but those kinds of business practices are infuriating.
