I’ve decided to resurrect an old idea and use a pool chlorine filter as the primary floatation for the buoy project. While I have been very attached to the yellow 3D printed sphere, I’ve had concerns that using an entirely 3D printed hull was not the most practical choice.
The canister will be water tight. It is made up to three pieces: a top part that will hold a round solar panel, a bottom piece to hold the electronics and battery, and a black gasket sandwiched in-between the top and bottom pieces which forms a water tight seal. The top/bottom parts were 3D printed in white ABS on a Lulzbot Taz 6, super awesome printer! I printed my own gasket from black Ninja Flex filament, is is very flexible and feels like rubber. Not sure how it will hold up to sea water… more experiments are needed!
The 3D printed parts are not yet water tight, so I’m going to try and infuse them with marine epoxy. Maybe I’ll try using a vacuum bag method or some way to force the epoxy into all the voids and crevices. This will give the parts added strength and make them suitable for being submerged underwater. Thats the thought, at least.
I’m use 316 stainless steel hardware ordered from McMaster-Carr. They have EVERYTHING! The twist-resistant threaded inserts were press-fit into the top of the canister after drilling out 4.7mm holes. They inserts appear to be holding up pretty well, even after repeated use. But it may be a good idea to use some epoxy for added strength during the installation. One change for next time, I’ll be ordering 10mm long machine screws.
The bottom part of the canister has two tabs that are designed to interlock with the pool float. These mimic the same functionality as the tabs molded into the lid of the pool float and provide a snap lock. To mount the canister into the pool float, you drop the canister into the float, insert to metal posts of the tool into the top of canister, and rotate 180 degrees to lock the canister securely in place.
The 3D printed tool has two metal posts, 1/8″ diameter riots, jammed into the handle. The metal posts fit into two receiving holes in the top of the canister and allow the user to lock the canister into the float.
The top piece of the canister will hold a round solar panel. I’ll use marine epoxy to secure it in place. The solar panel is rated for a 0.6W output. I am hopeful that I can drill a hole through the solar panel to allow the LoRa antenna to poke through. While this is a round solar panel, the actual solar cells are rectangular so there is some empty space on either side of the cells.