Most FDM Printers Are Also Filament Dryers (with A Little Help)

If you’ve printed with an FDM printer, you probably know there are many interrelated factors to getting a good print. One key item is the dryness of the filament. When you first crack your plastic open, it should be dry. Most filament is packed in a sealed bag with desiccant in it. But if you have the filament out for a while, it soaks up moisture from the air and that causes lots of problems. [Design Prototype Test] has built and bought filament dryers before, but now he would like to point out that every FDM printer with a heated bed can act as a filament dryer. You can see the details in the video below.

It turns out that the idea isn’t original, but it doesn’t seem to be one that has caught on. What the video shows though, is to take the idea and run with it. A 3D printed support sits on the bed and accepts a cheap PC fan. The whole affair gets boxed up with cardboard and can dry the filament.

The first test worked well, although the support was made of PLA and didn’t survive well. An ABS support tower was the answer. We hoped there were STL files for the support, but, apparently, they are only available to the channel’s supporters. However, a few minutes in any CAD program should let you duplicate the support easily.

The video mentions that the cover box could probably use more insulation. We would have been tempted to line the box inside and out with cork which is easy to work with and a great insulator. If your printer has a heated build chamber, you wouldn’t need the box anyway.

The video wraps up with how to store filament so you don’t get moisture in it to start with. He mentions vacuum chambers and reptile heaters. We’ve used a sealed container and few pounds of unused crystal kitty litter which is just a cheap way to buy silica gel.

We saw [Richard Horne] building a dry box years ago. Food dehydrators seem to work well, too.

13 thoughts on “Most FDM Printers Are Also Filament Dryers (with A Little Help)

  1. I’ve used the food dehydrator before. It didn’t work. It just deformed the filament and made it wavy to the point that it would jam my bowden tube. Maybe lower temp and longer drying time was the solution, but I don’t leave my filament out that often any more, so it’s a moot point. I keep it in an airtight box with some desiccant and haven’t had trouble since.

    1. Food dehydrators often dont let you set the drying temp. They just chooch away at one setting. PLA doesn’t need to be much more than 45c to dry. Dehydrators are often hotter than that. Just grab a cheapo ebay temp controller and hack it in. Worked with my printdry – which was hilariously badly designed from the factory. Since swapped out to a sonoff smart relay with a temp and humidity sensor. Now I just drive it with home assistant. Works perfectly.

  2. Since insulating my bed one of the more makeshift, quick and dirty solutions I’ve gotten a lot of mileage out of is to simply lay the filament spool on it’s side on the print bed then cover with foil. Create and up-side down ‘U’ shape tube of foil coming off the top and pointed into a container to server as a catch. Let it sit like that for a couple of hours. Has worked out for PETG, PLA and TPU with bed temps between 40C and 60C depending on which I’m drying.

    The solution in the article however will be nice when I need to re-spool filament, like the Novamaker PETG I had to respool last night after fighting against over-tension. Being able to re-spool and dry it at the same time would have been really nice.

  3. I’ve tried a couple different options, and my favorite is a thrift-store toaster oven with a cheap eBay PLC controller+SSR. $5 for the oven, $18 for the controller, and for under $25 you got an auto-tuning mini temperature chamber. I use it for filament and desiccant drying and baking on coatings.

  4. I’ve found that a “Sistema 3.5 L Bakery Box” is almost perfect to fit a roll of filament. It does have a little wasted space inside but it’s a lot closer than anything else I have found and the seal is very good.

    I first found these in a clearance store. Once they were out I only ever found them again on the internet and with crappy shipping prices. I get the impression that they didn’t sell to well for their intended purpose. I think it was cupcakes? Maybe if enough of us emailed Sistema they would start producing these and selling them through 3d printer supply companies or better yet make a perfectly sized version that gets rid of that wasted space.

    1. I use a 5l box as a spool holder, with a few silica gel packets thrown in. And I have a largish PTFE tube running from tangent to the spool through the side of the box to the extruder, both to shield that portion of filament and to act as a strain relief, guide and spool brake. Right now the hygrometer is reading 18% inside the box, with an ambient humidity at 60% at 21.7°C

  5. I think the principle of this whole idea of drying filament is a necessary evil. However you have to look at it in two different points a good quality food hydrator with an overnight run can easily make the filament a better product. And then using something as a food vacuum sealer is the next part in this process flow. I understand how others look at this problem but one thing with 3-D printing is a need for patience. Like most things if you rush it you get less than optimal results

  6. Ever since this design prototype test YouTuber cried about Michael’s (from teaching tech channel) style of presenting stating he’s only in it for the money and doesn’t care about 3d printing I lost all respect for this guy and never want to view any of his videos. I wish I could block channels on YouTube; I never want to accidentally support this guy.

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