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For perfect prints it is important to keep your filament dry and dust free. Best to store it in an air sealed box. Even better if it is possible to print your filament direct out of the box. In this post I show you how to build your own filament box which could hold up to 6 filament spools.
Built your DIY filament box
I decided to go with an already air-tight box to reduce the mess with the silicone sealant. All needed components, links to them, and a cost approximation are in the following bill of materials. Of course all the screws, nuts and threaded rods you can also grab at the hardware store.
Bill of materials for the filament box
Download all 3D print files (*.stl) in a zip folder here.
- 1 pc air-tight box* (approx. 17 EUR)
- 8 pcs M8 nut* (approx. 0,5 EUR / 10 pcs)
- 6 pcs pneumatic fitting with a M6 thread for a 4 mm tube (approx. 2 EUR / 10 pcs)
- 24 pcs guide roller including 608U bearing (approx. 15 EUR / 25 pcs)
- 1 m M8 threaded rod* (approx. 7 EUR)
- 1 m PTFE tube OD: 4 mm ID: 2 mm (approx. 1 EUR)
- 1 pc silica gel* (approx. 6 EUR)
- 6 pcs M3 screws* (approx. 1,5 EUR / 10 pcs)
- 2 pcs 3D printed rod mounts
- 6 pcs 3D printed fitting mounts
- 6 pcs 3D printed washers
- 6 pcs 3D printed nuts
- 6 pcs 3D printed flexible sealings
- or: silicone sealant* (approx. 7 EUR)
- optional: hygrometer* (approx. 12 EUR)
Without the printed parts and the hygrometer the costs are around 55 EUR. The box is capable to hold up to 6 filament spools, depending on their dimensions.
Instead of buying the assembled guide rollers you could also print the guide rollers yourself (included in the zip) and buy standard 608U ball bearings* (approx. 10 Eur / 16 pcs).
To seal the fitting mounts in the box it’s possible to use the printed flexible sealings or use silicon sealant.
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All parts were printed on my Prusa i3 MK3 with Prusament PETG Prusa Orange using a standard 0.4 mm nozzle. The rod mounts were printed with 0.2 mm layer height and 50% rectangular infill. The fitting mounts, nut, and washer were printed with 0.15 mm layer height and 50% rectangular infill. With the standard settings you going to need about 13h printing time. All parts together needs approx 130 g filament, which is about 4 EUR material costs.
If you going to use the printed flexible sealings instead of the silicone sealant, made mine with Fiberlogy Fiberflex 30D with a layer height of 0.2 mm. They are really tiny and only need a couple of minutes.
For the printed roller guides I used Prusament PETG Prusa Orange too with a layer height of 0.2 mm and 50% rectangular infill. Afterwards just press the ball bearing in the printed part, quite easy if you use a secound bearing to push it in.
Assembly instructions for the diy filament box
So you got all the parts, then start with cutting the threaded rod in two pieces, each 470 mm long. If you got another plastic box, then measure the inner length on the bottom of the box and subtract about 15 mm to get the needed rod length.
If you use the silicon sealant on the fitting mounts, apply about 2 mm sealant on the inner edge of the flange. Screw in the pneumatic fittings with the M6 thread in the printed fitting mounts.
With the printed flex sealing it’s far more easier, just put them over the fitting mounts. You find the 3D model of the flex sealing in the zip file, see the bill of materials section.
Place the threaded rods in one printed rod mount and secure them with two M8 nuts each. Slide 12 roller guides on each rod and fix the other printed rod mount with two M8 nuts each. The distance between the roller guides could be later adapted to fit the stored filament spools.
Now it’s time to drill the air-tight box, put be careful don’t push to hard – I was impatient and destroyed a box. First mark the locations, see following sketch for the positions I used for the box.
For the filament passage you going to need 16 mm holes. First I used a standard 4 mm drill and then a step drill to open them up to the 16 mm.
Expert tip: Mask the larger diameters on the step drill to avoid too large holes.
Fit in the prepared fitting mounts, keep an eye of the slant flange, this is meant to equalize the draft angle of the box. The thickest part of the flange should be oriented on top.
Then the washer is fitted on the printed fitting mount. Be cautious, the washer is also slant – the thinnest part should be on the top and the slant surface orientated to the box.
Secure the fitting and the washer with the nut, pay attention that the fitting mount and the washer did’t turn when you fasten the nut.
The same on all six fittings, to get the box ready for final assembly.
To close the pneumatic fittings with filament you don’t use you cut short PTFE tube pieces (approx. 10 cm) and screw in a M3 screw in one side.
Now put the spool holder, silica gel bag and hygrometer ind the box. Adjust the roller guides to hold your filament spools and place them. Insert the filament in the short closed PTFE tubes. Then close the cover to seal the box. If you need a specific filament for a print just pull out the closed PTFE tube and get the filament without opening the cover. Put on a longer open PTFE tube – I use a 20 cm tube – on the filament you want to use. This guides your filament and the small gap between tube and filament prevent moisture to get in the box. So you can leave the filament in your printer if you don’t use it.
Boom an there it is! Ready to take on the eternal war against moisture! Here some pictures of my setting with the Prusa i3 MK3.
22. Jan 2020 revision: Like Barry Mason in the comments mentioned – don’t place the hygrometer on top of the desiccant like I did on the picture, this will give false low reading. Put the hygrometer as far away from the desiccant to get an accurate reading of the environment.
To build the fancy filament guiding on the Prusa, just get a roller guide, a M8x20 screw, a M8 nut and the prusa filament guiding model in the zip file, see the bill of materials section. Happy Printing!