I have just recently started to dabble in TPU and some PETG CF and wanted to store them so that moisture cant really get to them. I bought some vacuum bags off amazon that ended up not keeping a seal longer than 12 hours so I tried to use my food sealer. The thing is though, the food sealer has a MUCH stronger vacuum and looks to be bending the spool quite aggressively. SEE PICTURES
The spool in the photos was sealed on the sealer’s “gentle” cycle but is still causing the edges of the spool to bend. Will this cause the spool to warp and stay warped if I were to continue to leave it in the bag? I am able to use the food sealer with a pulse method and can pull a vacuum on the bag just enough where the bag is void of most air and the edges of the spool has not started to bend, but I do like the idea of being able to seal the spool to a point where there is absolutely no air inside.
It looks like you are including desiccant in the vacuum bags. The desiccant removes the need to vacuum bag if there ever was a need.
I store my filament in poly cereal boxes and cannot pull a vacuum on them. In almost all of them I have fresh/good desiccant and a hygrometer. All like that report 10% RH which is the lowest the hygrometers can display.
A few didn’t have desiccant packs after drying but did have hygrometers. Those gradually crept up into the 20-30% humidity range over a few months - in well-sealed poly cereal containers. I had 4 or so without desiccant packs (ran out) and they all showed similar leakage.
Even poly cereal boxes allow water into filament but it’s a slow process and desiccant scavenges the water to keep humidity low. A few of us tried ziplock baggies to test their permeability and those leak water in just a few days. Food storage bags for vacuum sealing will presumably block water vapor a bit better but hard to know without bagging a hygrometer in there too.
The other thing about putting desiccant in with filament is if your desiccant isn’t well dried, you can be adding water to the filament in that nicely-sealed vacuum bag instead of protecting it.
I don’t know your experience with desiccants but if the desiccant is left out to grab water out of the air and then bagged with filament, the phone call is coming from inside the house. Desiccants used to keep filaments dry must themselves be dry or protecting filament can actually be making the issues worse.
Based on that very long thread I got a lot of great information, here’s a summary of what I’ve learned about moisture and storage from the ideas presented in that thread and my own “verified” experimentation. Read between the lines: Verify whatever is said here, just don’t take my word or the word of anyone else!!!
What may look watertight is not necessarily so. Given enough time, plastic containers will allow water to migrate inside, even those with a tight rubber seal.
Desiccants don’t dry filaments; they dry air. The dry air helps prevent latent moisture from re-entering already dried spools. Read between the lines here: If you put a wet spool into a sealed enclosure with desiccant, you end up with wet desiccant and drier air—but not necessarily drier filament. I suppose that, given a few years in a dry-air environment, an argument could be made that it would dry the spool. But absent that amount of time, you need to heat the spool to force the internal moisture to escape. That’s what spool dryers are for.
Sucking all the air out really helps deform your spool—if that’s what you’re going for. Most of us would consider that bad. But you already knew that. The only purpose of over-vacuuming a bag is to visually confirm negative air pressure, assuring the seal is intact. Beyond that, it serves no purpose.
Many people swear by exotic forms of dehydration storage—like $100 sieves for a single spool. Not exactly economical.
Did you know that a cheap $0.40 moisture indicator card can tell you at a glance how much humidity the storage vessel absorbed over time? A cheap hygrometer will tell you how much moisture is in the bag at that moment, but it won’t tell you how much was absorbed over time. Also, those cheap indicator cards can be dried and reused multiple times.
My experiments have shown that a reusable storage bag with desiccant and a moisture indicator card works just as well whether I vacuum seal it or not. Try it for yourself: set up one vacuum-sealed bag and another that’s just ziplocked, then leave them in a corner for a couple of months. Compare the indicator cards. You’ll find no significant difference.
Recommendations based on practical experience:
Don’t over-vacuum – Over time, you’ll ruin the shape of the spool. It doesn’t provide any real advantage. The difference in air volume between a tight bag and a looser one is negligible in terms of absolute humidity. A decent 50g desiccant bag is more than enough to keep things dry inside. This is especially true for partially used spools, where less filament means less structural reinforcement.
Instead, vacuum just enough to visually confirm negative pressure.
Food vacuum sealers may feel reassuring, but they’re not better than reusable bags. They’re just a pain in the ass when you need to reseal. A quick-store, resealable bag ensures you’re more likely to actually put the spool away—even if you forget to vacuum seal it. If I had to rely on a heat-sealing food vacuum, I’d be far less likely to do it in real time and would probably forget altogether.
Comparison shop “Filament” bags versus food storage bags. Often a search on Amazon and you will find the exact same bag under food storage for about 25%-50% less. Imagine my chagrin when I found identical bags but better sized in the food storage section of Amazon for 50% less.Also, I found that many of the filament bags were oversized whereas you can get smaller right-sized food bags that fit a 1Kg spool perfectly. But note, prices change frequently.
Thank you for the reply! I am considering more of long term storage. Several months to maybe even a year. I don’t use those filaments often. For pla and petg, I don’t even bother with bagging or desiccant. Use them up with in 2-4 months. Haven’t had any issues except with some translucent petg but several hours in a dryer helped that
Also, I work for an outdoor store that gives 50% off anything store branded so I am using cut to size bags for less than $1/ft and a professional sealer that only takes 5 seconds to seal. I cut the bags a bit longer than needed so that I have a few seals in the life of the bag. I will just evacuate the air to a point that it is negative pressure and call it a day. Really don’t want to damage any of my spools
Not to name drop or anything, there are similar, but sometimes knowing good quality or what works helps a lot.
I actually product tested this very thing a long while ago - still using it! brilliant little thing and kit. vac bags from elegoo of all people. https://www.amazon.ca/gp/product/B0D499PXXB
So far only 1 bag has punctured because I’m an idiot and idiotically snipped my filament to a sharp point and left it pointing out. so obviously it would punch through doh!
I over vac to death, no issues yet and I have one of these in each vac bag as well. they are FOR LIFE! you can just microwave them to recharge. Love these things!
Their little pump makes short work of the sealing taking less than a minute, zips are ultra strong really no issues. Then I just pile all the bags into a large storage tupperware bin for toys there? and voila! I have filaments dating back to when the CR10 was released like this and they all work no problems here on the mini.
Edit: in his tent house too as I leave spools in here haha. Got like 8 around the base. (Canada. Winter. -20. he be cold and needs a tent haha)
Most of us would consider that bad. 
But you already knew that. The only purpose of over-vacuuming a bag is to visually confirm negative air pressure, assuring the seal is intact. Beyond that, it serves no purpose.
Also, I found that many of the filament bags were oversized whereas you can get smaller 
