I 3D printed a hollow float for my ROV, but I would like to fill it with foam instead of leaving it full of air to handle deeper working depths.
I've debated using spray foam, but from what I've heard, it absorbs a lot of water. That shouldn't be a problem if my float is waterproof, but if there is a leak the robot might not come up. That, and since it is open cell, it would collapse under depth.
The other option I've considered is making my own syntactic foam, but that might be expensive. I have also yet to find a place (here in Sweden) which sells mikrobaloons that are strong. The only ones I've found in Sweden are these: https://primenta.se/komposit/additiv/mi ... -19-g.html
Would spray foam work? Should I go with Syntactic foam instead? Has anyone else done this and found a floating material?