update: link to CAD files
Finished printing the latest hull design This had to be printed in three sections due to issues with excessive overhang at the bottom portion of the hull, and is held together using M3 stainless steel cap screws. There is a hole in the center of the bottom section so an analog temperature sensor can be installed and potted.
Initially the top portion of the hull was intended to be clear. During the first attempt to print the top, the printer jammed after 80% of the part had been printed. Unfortunately I will have to order more clear filament, so in the mean time I can pressure test with this yellow print (which finished without any issues).
Next I plan to cover the exterior in clear epoxy to seal any voids or cracks in the prints and then pressure test the hull design with the o-ring installed to see if it will stay water-tight at 3m depth for 60 minutes. This buoy design is intended to float at the surface, so the pressures will be much less, but I want to test at an extreme condition to make sure it will not leak over extended use. Those electronics and sensors are expensive!