Filament Dry Box Port, 3mm

I had the need for a dry box for the active filament reel being printed with, as my long prints would allow the PLA to absorb moisture from the air and cause print problems. Most of the designs I found were for 1.75mm printers while I have a 3mm printer.

It needed to stay relatively dry so I found a container with a good air tight seal. I then designed this port that the PTFE tube from the printer could directly passthrough while also providing a good air tight seal.

Parts:

Numbers below are from the packaging. I wish we Americans would switch to the metric system; so sorry about the mixed measurement systems.

Parts:
(1) Snapware 40 cup (9.5L) container (https://www.amazon.com/Snapware-Airtight-Rectangular-Storage-Container/dp/B007V4IWIU/)
(3) O-rings, 11/32" O.D. x 7/32" I.D. x 1/16"
(2) Neoprene washers 5/32" for the mounting screws
(1) Neoprene washer 7/16" for the main PTFE tube hole
(2) Two screws and nuts that I had sitting around that fit
(2) Two of the printed parts (they are symmetrical)

Useful Tools:
Hole Reamer Tool (https://www.amazon.com/Hobbypark-0-14mm-Puncher-Reamer-Drills/dp/B01EIH573K)

Instructions:
Print two of the parts using a fine setting; one for the outside and one for the inside of the container. Using the fine setting provides good surfaces for the inside mounted O-rings.

Insert two O-rings into one printed port. This will be the inner port. There are two races for O-rings in the design on the inside. I used a dull dental pick to guide the inner most first, then worked on the outer most.

Insert one O-ring into the other port. This will be the outer port. I used the outer most race as there is no need for two O-rings and this one is meant to provide stability rather than any sort of a seal.

Cut three holes aligned with the holes on the printed port in the side of your box. While I placed this near the center height wise, I think it would have been better at about 1/3 from the bottom. I used a hole reamer tool that can just be pressed and rotated to create a hole of any size up to the max of its taper. If you work in plastic much, you will want one of these. Use the inner hole size of the neoprene washers as a guide to the size of the holes to cut.

First loosely assemble all the parts with the neoprene washers on the inside of the box and the port with two O-rings also on the inside. I used the PTFE tube already inserted to make sure everything lined up. Align the ports so one points upward and the other downward so it fits your use. Then slowly tighten the screws while you make sure the neoprene washers are aligned well to provide a seal. Once snug, tighten a little more to slightly compress the washers without causing any stress on other parts.

Hint: Rotating the PTFE tube while you insert into the port will allow it more easily go in.