fppf
Contributor
I just use plan PVC.
I went a little more complex, on the end screw in cap I drilled and tapped an 1/8" NPT port. Then screwed in a small ball valve. The PVC empty will make the rig positive. Then I just open the valve a little at a time until the rig becomes neutral. This provides a way to adjust the buoyancy. Once its set the PVC does not crush so it never changes. Works great in fresh and salt water.
I went a little more complex, on the end screw in cap I drilled and tapped an 1/8" NPT port. Then screwed in a small ball valve. The PVC empty will make the rig positive. Then I just open the valve a little at a time until the rig becomes neutral. This provides a way to adjust the buoyancy. Once its set the PVC does not crush so it never changes. Works great in fresh and salt water.