If it makes you feel any better, mine say
95% 95% 95% 95% 95%
Edit: Correction….97%
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Yes, it makes me feel much better - as long as I don’t remind myself that this is our dry season! 
Thank you for sharing that, I know I am not alone - why is there this disconnect between those who think that filament needs to be at 10% or it won’t work, and those of us who print under water and it seems to be fine? Is the internet making me worry too much?
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Did you just see this one, https://youtu.be/tmbZVmXyOXM?si=AQkMjEXoh8WfkbpY&t=910, This chart I marked is over my head. At least on the first time around watching it. It does seem to be exactly what you are trying to do here though. I think…
He mentions what climates those towers do not work in, opposite of what I would have though. This is a complicated subject.
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Good old coastal living. It has a lot going for it but low humidity levels is not one of those things!
Yeah, that’s definitely a critical point. There are two effects, one is that the gel is increasing in temperature, the other is that the air is lowering in RH, both of which will decrease the gel’s ability to hold moisture.
That’s definitely an interesting consideration. I’d say without further information I’d consider it a scaling factor on top. Maybe I’ll try turn it into a surface plot after lunch.
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I’m a big fan of them. I have 3 of the Mitsubishi MJ-E22VX units. I’ve bought all of them 2nd hand for about 1/4 to 1/3 their new price. They’re pretty easy to open and give a quick clean out. On my to-do list is to figure out a way to benchmark them to make sure they’re still operating effectively.
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The penny dropped in his summary - I suspect that even what we are talking about now needs a different solution for different climatic conditions - life at 30° is different to life at 10°. It doesn’t explain why we don’t seem to have the extreme problem with filaments that those in cooler climates seem to have. Maybe it’s like putting water into hot fat - with the filament already ten or twenty degrees warmer the water evaporates out of it before it hits the hot end?
That could explain my observation that “warming” the filament in the “dryer” while it is being printed rather than waiting a couple of hours for it to “dry” is sufficient to make a difference?
Perhaps this is another case of " what you don’t know can’t hurt you!"
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That’s entirely based on density vs humidity, though. I don’t think anything from that video is relevant here?
I’m personally not going to put too much effort into the effects described in the video, I think it’s entirely irrelevant here for the most part. I do think it’s a case of different conditions being important.
I suspect your warming scenario is that the outer layers heat faster and dry faster, so hot filament going into the printer will always inherently be taking outer/hotter layers and so they dry much faster than the inner layers.
To think of it another way, putting the filament in the dryer for 10 minutes will heat and potentially dry the outside layer of filament but do nothing for the inside. Sealing it up then means the entire thing re-equillibrates to mostly where it was before. Even drying it for hours might not drive it to completion if it’s a tightly wound plastic spool in a dryer with poor airflow. It’s not the heat that’s drying the filament, it’s the exposure to heat plus low RH. If you were to keep the filament mostly sealed in an enclosure, heat it and then let it cool, there’s not a lot of drying going on! On the other hand, having the outer layer be hot and with a bit of airflow around it means it’s probably drying pretty decently quickly.
If you had the right conditions you could potentially dry the filament at the point of use by passing it through a hot air column. That’s another thing that’d be interesting, do the same whole-roll filament tests but over shorter timeframes and with individual strands and high airflow conditions.
That’s kind of how the defect in the Eibos design works - the hot air is directed at the outer surface of the spool - the downside in that case is that a stationary spool will get hot enough for the filament to fuse together!
Hmmm, that’s an interesting scenario. The Creality one seems ok in that it measure the input air temperature and seems to get the filament relatively evenly warm. That certainly doesn’t sound ideal…
Another strike for a number of youtubers - scientifically measured moisture loss, of course it will dry nylon, and a wet sponge, it’s pumping air at 75°, directly onto the surface of the spool 20mm away!
There are some fixes on the way, but I’ll deal with that later. As long as the filament is moving it is very effective, so it will remain as my dry box when printing I think.
I missed your post - you may have noticed that I have ordered another one- having given mine away when I bought the snazzy Eibos. It worked perfectly so the new one will too - its weakness is that it doesn’t act as a “dry box” when printing.
Sd
Agreed - as noted above, perhaps a low wattage heater and a small fan to keep air circulating and a vent in the top to release wet air, is all that’s needed.
No more theories (from me) let’s go one step at a time - next week - chop up the new dehydrator!
I think constant drying using a small fan is probably a good way to keep the humidity slightly lower than the room ambient but not a good way to actually keep things dry.
That’s how a lot of the dryers for things like gun safes work, they’re just a ~40W element or whatever that keeps the inside warmer than the outside. If you do that, things inherently stay at least somewhat drier than outside because the partial pressure of water vapour remains the same, despite the relative humidity, so there’s no shifting of water from one air volume to the other or anything like that. Same way enclosure heaters for electronics works.
So far I can’t come up with anything better than the recipe I mentioned above. Dry the filament thoroughly and then keep it sealed, either hermetically or in a box with sufficient buffer (dry dessicant) to extend the lifespan out long enough to use it.
I should really add a temperature/humidity sensor in the dryer so I can track it with Home Assistant.
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How simple (read cheap) is that to do?
Yeah, that was the track I was on - it’s the leakage of the boxes that is my problem, and now ten boxes (20 spools) of filament to dry again and silica gel to dry again - I’m chasing my tail!
Do you actually need 20 spools on the go at once? Perhaps consider a long term/short term type storage solution? I have the one spool I’m using in the dryer and the other ones have a fresh bag of dessicant and is in a ziplock bag which should be a lot closer to zero air leakage. I was intending to get a bin and a bunch of dessicant but haven’t gotten to that point yet.
Pretty remarkably cheap and simple. I started out with a spare Raspberry Pi to run Home Assistant to do all the logging/visualisation. I use a bunch of Xiaomi bluetooth LE temp/humidity sensors like these ones:
That can be re-flashed with a replacement firmware to reduce energy usage and make them slightly easier to interface to.
I have them all around the house and use ESP32 devkits running ESPHome to do the BLE to WiFi part of it.
Well worth having a play with. It’s the most straightforward method I’ve found for getting a full logging/monitoring/alerting setup without getting caught buying expensive stuff or getting caught in a pay-as-you-go ecosystem.
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No but 20 opened, the “airtight” boxes were supposed to be the medium term! I had ziplocks before but they also leak over time. The long term storage (ASA and FLEX) I vac seal.
I do access at least ten regularly - when I am printing images (more if that to come) there are at least six or up to ten at once out - a lot of my thought process at the moment is pre-emptory, but the last project had 100 tiles each with seven (manual) colour changes.
So it’s not quite an engineering “grey is good” situation.
My wife is convinced that if there was an XL in our lives I would produce more, I am not convinced!
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Yeah, definitely a different use case. I’m almost entirely on the functional printing side so I’m typically choosing which filament to load by type rather than colour.
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My first thought is that you are trying to talk about thermodynamics on the Internet and it won’t end well. 
.
After looking a little closer, this seems plausible. I have two concerns:
- You are moving air between these buckets. That will move a lot of heat against the TEC heat differential you are trying to make. Pumping cool air into the hot container of silica will fight the TEC. Depending on how fast that happens, you may need 10x more energy to keep the same differential (the 10x is from my gut and not from any engineering whatsoever).
- When you switch to cycle B, where are these outside air arrows going and coming from? I assume the inlet and outlet on the left is from ambient (so it has 70-90% of that Texas humidity?) and the right inlet and outlet are from a drybox with your filament? The amount of moisture each of those has to handle is going to determine the size of the system. If you have to move 1g of water per hour vs 100g, the size of the whole system will have to change.
The final outcome would be based on if this system with some reasonably sized TECs can move enough water to overcome the losses due to leakage and be effective enough to not pay $20 to dehumidify a single spool of filament. I would love to do some math to tell you that 100W would move X grams of water. But I don’t know if you can be that confident considering the losses of moving air between containers you are trying to heat/cool.
But you have my stamp of approval for a medium scale prototype 
. What would you measure to test it? The weight of the silica in stages throughout the process? The weight of the filament in the drybox?
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I use these same sensors and they feel like magic.
That is really interesting because we run humidifiers during the winter to try and keep our lungs operating well. Our RH is often below 30%, which is recommended for good health. There isn’t really a good solution for himidifying the whole house and the room based ones only work when you close the doors. We usually put one in the bedrooms at night and that adds a lot of chores cleaning and disinfecting them.
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Yeah, the temperature sensors are great for what they cost. Not ‘super’ accurate and kinda slow response time but more than good enough.
The humidity thing is the same issue just from a different direction, I guess.
Thinking about it, it’s not that different from some places needing heating, some places needing cooling, some places needing both, perhaps?
Mine too (FWIW)! 
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I can send you a bottle of compressed air from here - might be enough humidity to get you through winter! Seriously - that is not comprehensible! 
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