Hey Matt.
Finished the rig last week (looottts of help from my Dad) and took it out. Unfortunately, our temporary trim adjustment mechanism (bits of pool noodle attached to loc-line arms near light cannons) didn't stay put, so I wasn't able to test the thing in reasonable conditions. Grr.
Ended up diving without any buoyancy on the lights, and boy was that a downer. Not easy at all. Definitely am going to need a pile of buoyancy on those lights. I think they need to be more than just neutrally buoyant. If they are positively buoyant, they should tend to pull the whole rig upright. My housing is pretty buoyant itself, so the thing will want to float face down if it is neutrally buoyant I believe. I'm going to have to make the lights positively buoyant, and the bottom bar of the rig itself negatively buoyant, to provide proper trim.
If you (or anybody) has some ideas on how to make the lights positively buoyant (except for removing the batteries, ha ha), I'd love to hear them. We are currently looking at a substance that is a substrate (putty like) with hollow glass beads mixed in. It is a putty like texture when wet, and dries hard. So it won't compress at depth like foam would. I can get the name and info on it if you're interested, but I'm not sure it's going to work yet.
My dad worked out a way to attach safety wires inside the loc-line - I'm pasting it below, in case it helps you or anybody else out.
Another thing to think about is drain holes in the loc-line. That stuff will fill with water and the water will never come out (or at least not until it is in the trunk of your car on the ride home!) without them.
The loc-line was not stiff enough to support light cannons at rakish angles in air. Nor was it stiff enough to support light cannons "au natural" in the water. I think once the light cannons are neutrally buoyant, however, stuffness will not be an issue. There seemed to be no strength issue when hoisting the rig out of the water by the handle, letting the light cannons (crossed across camera) dangle. But the safety wire inside the loc-line (thank you for the excellent idea) provides peace of mind nevertheless.
"Safety wire for use inside Loc-Line. ( L-L)
This assembly was designed to work with a 3/4 inch L-L assembly
13.5" long including the base mount parts at each end.
It could readily be scaled to a smaller loc-line.
The wire is .040 diameter 304 Stainless commonly used as aircraft
safety wire.
The brass parts ( BP )at the end were cut from a 3/4 inch round brass
bar. They are 0.3 inch thick. The wire is silver soldered into a .046
dia. hole in the inner face of the BP. The outer face of the BP is rounded at the edge so it fits flat in the bottom of the L-L fixed mounts.
The wire is 23" long which allows for possible longer L-L later.
The wire was coiled around a 5/8 rod which allows for a slip fit
inside the 3/4 id of the L-L. The reason for using a longer, but coiled line, is that when the L-L is bent, the length of the wire changes ever so slightly. A tight wire
would make the L-L harder to manipulate.
I used silver solder because it is strong and was available. Soft
solder may work fine. Give it a good pull test.
The second .046 hole in each BP was for a second wire. Since I
couldn't break the first one I skipped the second."
The outer face of the BP has a tapped hole into which is screwed the threaded brass rod which forms the core of my hand grips.
I am going to try to attach pictures. May not work the first time.
There should be two jpg files attached. Hope this works.
Taxgeek