Super Cheap and Simple 3D Filament Dryer

So I have a 3D printer and was getting horrible finish on my prints with some of my filaments. Once I realized it was because my filaments had absorbed humidity, I looked for ways to dry them.

I first did it in my oven, but it’s annoying because it’ll only go down as far at 170 Fahrenheit, which is still too hot for many filaments; I ended up having to monitor it and turn it on for 30 seconds every 20 minutes for 4 hours. Not my idea of a good time.

Then I made this. I had a little trial and error with the wattage of the bulb, but after trying 40 watts (got too 35c/95f, not enough), a 60 watt bulb (45c/113F, still not enough), then a 100 watts bulb (perfect, hovers around 50-52c/122-125F), everything was settled. If you use a less insulated box or a bigger box, you might need bigger, but that might become a bit of a concern (hot things in a cardboard box).

Putting it together was about 30 minutes (including wiring the fans and fetching the items), and it’s all made from crap I had lying around; not the sexiest, but it’s free and it works. Used it twice, and it works perfectly. So here goes.

Step 1: Materials Needed

Materials needed:

To make this super easy, super cheap filament Dryer you will need the following (or equivalent):

-1 insulated “good food” box (any box will do, the thicker the cardboard, the better, but the good box box has actual aluminum lined insulation, so it’s perfect). Mine is about 28x33x35 cm (11x12x13 inches or so)

-one super cheap light socket, wired to plug in an electrical socket

-one 100 watt bulb (not fluorescent of LED. You need the good old inefficient bulbs that put out tons of heat)

-a 2-3 small fans with something to power them (I used a bunch of fans from a pc, I powered them with a 12v adaptor)

-one dowel at least the length of the smallest side of your box (actually 2-5cm/1 inch longer)

-one probed thermometer (I have a wired one, but one with a needle that you stick in things would work too, as long as it’s somewhat precise)

-various hand tools, that can all be replaced by a pencil or a knife, if you’re in a bind (that is once your light and fans are wired. I’m not explaining those steps here, but instructions are easy to find everywhere online).

Step 2: Making Air Holes

The first thing you'll need to do is make some holes for the clean air to come in and the hot, wet air to leave.

To do this, I used a 1 1/4 inch (5cm?) Hole saw, but a simple knife can be used to make holes about 1-2 inches across.

For the location, I made two holes on each long side of the box, one that will be on top (exhaust) of the functional dryer and one that will be on the bottom (intake) for each "side a" and "side b" (see image, on which the box is laying down "normal", but on what will be one of the sides when it's done). On the image, the red dots are the spots to hole up... Location is somewhat suggestive, but far from the law. I made them so they cover the 4 corners of the box... ish.

Step 3: Making Holes for the Dowel (the Filament Spool Holder

Here is where your pencil (and a ruler) comes handy.

The filament spools are held by a dowel that goes across the box, and is to be as far from the light bulb as possible.

To do this, for regular sized spools, you poke a whole with your pencil about 6-7 inches (15-20 cm) away from the lower left corner (on side a, the side b is the opposite).

Then you run your dowel through so that it pokes out from both sides, and is held there by the holes in the box. you might need to force it through, but that's ok, even if the hole is a little ragged, we don't need a super tight fit.

On the image, it's the red dots.

Step 4: ​Done...ish.

Essentially, since you’re already supposed to have wired your fan and your light, all you got to do it put the stuff in and run it.

I have three fan, and all three run all the time. One of those is right against the bottom hole on the right side, to pump in fresh air. The other two are resting on the wire for the lamp, to keep them propped up and able to draw air (if they are flat against the bottom, they won’t move any air). Someone less lazy might make themselves some kind of a more permanent prop…

The light itself can be put straight on the bottom, or, as I did, stuck on the side. I simply held it there with a screw in one of the fixture’s hole, that goes in the cardboard. Not the sturdiest mount, I might pierce a bolt through and put a nut on the outside (with a washer) soon enough.

The wires for the fans and the light simply snake out from the "door", the opening. You can squeeze the door on it and it closes well. again, a tight box is not a priority.

As for the thermometer, I put mine on top, with the probe going in through one of the exhaust hole. If you have one with a needle probe, simply poke it through the top so it’s close to the filament.

Step 5: Running the Dryer

To load up to three spools, all you have to do is pull the dowel on one side, put the spool(s) in the box, and then run the dowel through the spool(s) and out the other side of the box.

once the spools are loaded, you close the door tight (as tight as it goes, gaps are NOT an issue), plug in everything and then monitor the temperature.

My set up takes about 1 hour to heat up to 49-51 celsius (120-125F), which is perfect. It mostly hovers around there, but I've caught it at 52 ish. To regulate the temperature, you can crack the "door" open a little. And by little, I mean, 1/8th, or 1/4 of an inch (5-10mm); that has been plenty to keep the temp just where I want it.

When I ran mine, I put in spools, but also dessicant, whie I was at it. my hygrometer told me that the humidity level in the box was less than 10%, which is perfect. After 4-6 hours, I took everything out, and printing showed me it was perfectly dry. I monitored the first run regularly, and my second use of it, I looked at it every hour or so, with no need to do anything.

Running it for this long with a 100w bulb is going to cost less than 50 cents (for me, where electricity is cheap, it was more, like 10 cents).

So there you go! Inquiries and comments welcomed!