Magnetic PTFE Dry Box Fittings

thingiverse

These connectors are designed to provide a tight seal from a filament dry box to a printer. They feature magnets, making it easy to switch boxes or change filament. This idea was inspired by [Thing 4402034](https://www.thingiverse.com/thing:4402034) but the design is unique to me. The main difference lies in the number of magnets and how they connect. My design requires two magnets so that any two connectors will work together seamlessly. On each connector, one magnet is recessed slightly while the other protrudes slightly, ensuring a positive connection and preventing binding. ### Bill of Materials The quantity of each part depends on your specific use case. The quantities listed are for one PTFE tube from a dry box to a printer with o-rings sealing the dry box and each connection. You can choose to replace the o-ring parts with non-o-ring parts if you feel this level of sealing is excessive. #### Printed Parts - 1x Dry Box Dual Block - 1x Dry Box Dual Backing - 1x PTFE Block - 2x PTFE Block (O-Ring) - 2x Cap Block (O-Ring) #### Purchased Parts - 2x M3 8mm Bolts - 2x M3 Nuts - 6x 4.5x2mm O-Rings - 2x 3x1mm O-Rings - 3x [PC4-M10 PTFE Push Fittings](https://www.amazon.com/dp/B078SRBDS7) - 14x [1/4" x 1/8" N42 Neodymium Disc Magnets](https://www.kjmagnetics.com/proddetail.asp?prod=D42) ### Assembly #### Magnets Each connector requires two magnets with opposing polarity. All connectors should have their magnets installed in the same way, with all protruding magnets having the same polarity and all recessed magnets having the opposite polarity of those protruding. Magnets are pressed into their holes and should be snug so that they do not come out when separating two connectors. I typically press the connector down on a table to fully seat the protruding magnet. An M3 nut or another magnet can be placed on top of the recessed magnet when pushing down to fully seat it. These connectors are designed to work with K&J Magnetics' D52 magnets. There is some small variance in the outer diameter of the magnets. If you find that a magnet does not stay in the connector, you may be able to swap it for another one. However, I find this is rarely necessary if your printer is consistent. #### O-Rings The 4.5x2mm o-rings are used to seal the connectors. The connectors with a recess of this size around the filament hole should have an o-ring pressed in. The o-ring will protrude slightly, allowing a positive seal against the opposite connector. #### PTFE Fittings The PC4-M10 fittings should be snug but do not overtighten them. Doing so may damage the printed plastic part. The length of PTFE tube from the box to the printer should have one PTFE fitting with an o-ring and one without. The PTFE on the printer should have an o-ring, allowing each connection between the dry box and the printer to be sealed tightly. #### Dry Box Fittings The dry box fittings are designed specifically to work with [Thing 4493689](https://www.thingiverse.com/thing:4493689). The filament holes are spaced at 80mm and will likely work well with other DIY dry boxes. These fittings use 4.5x2mm o-rings to seal the filament holes and 3x1mm o-rings to seal the M3 bolts used to attach them to the box. All four o-rings are installed on the outside block. Insert the bolts through the outside block and then place the 3x1mm o-rings onto the bolts. The two nuts sit inside the hex-shaped holes in the inside block. You will need to drill holes in the box for the bolts and filament to pass through. Once done, you can install the fittings and tighten the bolts so that the front block sits flush against the outside of the box.