We learned a lot from the first couple of tries and completely reworked the design not only to make it more water resistant but also more functional. Printing at 100% takes a long time and it would be nice to have a case that is actually useful when it's done.
The walls on this version are 3mm vs 2mm in the previous version. We also used 45 degree angles instead of curves and kept all the overhang for the seals to the outside rather than interior of the case.
The hinges are sturdier and the latches are redesigned (but not sure yet if they are better). We also added in a hook system and gummy rubber bands to turn the lid's interior volume into a separate storage area. On the exterior there are little loops for straps or handles.
Looking at the cross section shows how the seal is created. The 6mm aquarium tubing is placed in the U-channel on the bottom half of the case. The top lid has a triangular ridge that presses into the tubing hopefully creating a seal.
We're using silicone tubing and using a slightly smaller diameter section of tube to connect the cut ends of the tube.
It is important to stress that this is water resistant and not "waterproof." The difference is that this case can sit in the rain or take a dunk and keep water out but if you submerge it for more than 10 minutes or so moisture might start making its way in. It's a poor man's Pelican case. Pelican cases are made of molded plastic which, unlike 3D printed plastic, have no gaps between layers for water to enter. The seals are also professionally designed and manufactured.