Doubles and Spinning Isolator

[hydro12]

So I've read and watched many detailed instructions on assembling doubles and how the isolator bar should spin with little/no resistance once the doubles are assembled. So far, I'm good.

However, they don't mention if it should still spin freely when pressurized (I assume so, because the whole point is knocking an overhead object and wanting the isolator to freely spin backwards instead of shearing off). This is where I'm not so good - once my cylinders are pressurized, isolator bar no twisty - which makes sense to me being that pressure has a tendency to do that to thing (my first stage not wanting to swivel once pressurized, etc.).

Is this copacetic or not so much?

[in_cavediver]

OK, I am speaking about the barrel sealed manifolds. I don't have expierence with the Face sealed variants.

When assembled, the isolator shoud rotate somewhat freely but not more than a turn or so. This is as much due to the tolerances in the bands and the need to position the isolator valve. Once position, there should be two nuts, one right hand thread and one left hand thread. These should be tightened to 'lock' the isolator in position. I personally don't want my isolator moving during a dive.

[hydro12]

Thanks for the reply cavediver.

I think I may have figured it out - breathed doubles down to about 400 psi and the isolator bar (barrel o-ring) spins again (only about 180 degrees or so). What I'm thinking is the filling of the tanks probably caused them to expand exerting pressure on the bands and making the isolator bar not want to turn. If that's the case, I assume when I feel them again, I can check and then probably just loosen the bolts on the bands a bit.

[Jimmer]

Thanks for the reply cavediver.

I think I may have figured it out - breathed doubles down to about 400 psi and the isolator bar (barrel o-ring) spins again (only about 180 degrees or so). What I'm thinking is the filling of the tanks probably caused them to expand exerting pressure on the bands and making the isolator bar not want to turn. If that's the case, I assume when I feel them again, I can check and then probably just loosen the bolts on the bands a bit.

Yeah the pressure will effectively "lock" it in place, that said I use the locknuts like Cavediver to set mine where I want the isolator knob and it doesn't move.