How delicate are manifolds?

[Belmont]

I've been using the same cart, please share some stories so I can avoid that situation and not be left on the side of the road with a broken cart and a set of doubles......

It's the plastic parts. The wheels go first. Use them only on paved or very smooth surfaces.

I'm looking at an industrial type aluminum hand cart with tires. I have to lug twin 130's at the fill station.

Next season we'll have a 30 foot whip and be able to fill twins right in the customer's "boot".

BTW the word "boot" in the UK and Australia is used to designate the trunk of a car, not just things you put at the end of your legs and/or tanks.

I guess it goes well describing a part of a car with a right handed steering wheel.

Cheers matey.

 

[duckbill]

Different manifolds are different strengths.
Different tanks have different weights.
No one answer.

The old school way was to lift by the manifold. Then, in the early '60s manufacturers started attaching a handle to the side of the tank band on some of their double tank systems.

I try to not carry from the middle of the manifold where the valve/yoke is. As mentioned before, carrying out to the sides with two hands is the best way to carry if you must carry by the manifold at all. And as also mantioned, make sure the bands are tight. Don't carry by the manifold at all if the tanks are out of the bands!

 

[Sas]

Well I've kind of got a mixed bag of advice asking around as well as reading about it...

I think just in case, I will try to use other methods than lifting by the manifold. Given it is new and shiny and I don't want it to break too soon!

 

[Katamuki]

Saspotato, I made a quick sling out of 5/8" rope that makes a loop around each valve and lets me hoist the doubles on my shoulder. Makes it easy to carry and ties/unties in seconds.

 

[Sas]

Saspotato, I made a quick sling out of 5/8" rope that makes a loop around each valve and lets me hoist the doubles on my shoulder. Makes it easy to carry and ties/unties in seconds.

Ok fair enough. Not sure I have the upper body strength to hoist them onto my back like that but I have to say carrying these around a few times a week, and up and down ladders, has made a difference to my strength! So maybe eventually Getting them on my back from ground level, usually I stand them up on the ground, put the harness on sitting on the ground, then roll to one side, onto my knees then push up from there. Not very glamerous but my boot (also known as a 'trunk', thanks Belmont ) has a lip unfortunately so if there is nothing at the right height it is off the ground level. Once I tried to put them in the boot by resting on the lip and slipping them off my back and ended up landing in my boot on my back like a turtle. :blush: And getting stuck until a passerby freed me.

 

[DA Aquamaster]

PLus 1 or 2 or 3 on the "don't leave the isolator loose" comments. It's another one of those good ideas that really isn't. It protcts you from an extemely unlikely failure event at the cost of creating a much more likely failure. A really bad idea.

As noted above, if you impact a cave hard enough to shear the isolator knob, you will have far larger problems with your much softer and now badly dented head.

 

[Sas]

PLus 1 or 2 or 3 on the "don't leave the isolator loose" comments. It's another one of those good ideas that really isn't. It protcts you from an extemely unlikely failure event at the cost of creating a much more likely failure. A really bad idea.

As noted above, if you impact a cave hard enough to shear the isolator knob, you will have far larger problems with your much softer and now badly dented head.

I checked it again when I got home. It moves about the same distance as mentioned here. The locking nuts are loose though. (edit: loose as in finger tight, if that makes sense)

 

[Colliam7]

A few people have told me never to lift it by the manifold as it can damage it and a few more people have told me they've been lifting their twins by the manifold since the dawn of time with no issues.

I am one of the "since the dawn of time guys", altouigh in polite company to avoid having ti explain it or argue it, I will lift by the knobs, not the isolator bar. ... Personally, when I look at the construction of the valve knobs and the short but small diameter valve stem that secures the knobs, it becomes obvious that it must endure a great deal of the lifting forces when you use the knobs and that strikes me as being just as bad or worse than lifting by the isolator. There is clearance between knob and valve, so the stem either has to take all the load or flex slightly to share the load with the valve body.

I will echo what DA said. I have had the experience of (unthinkingly) lifting a set of HP120s by the valve handles - NOT the valves themselves, but by the handles - and bending one of the metal stems. The valve still worked, but I ended up replacing the stem because of the awkward rotation of the valve handle.

One thing that comes across in the early part of the thread is something of an 'either-or' opinion on lifting doubles by the isolator manifold vs the valve handles. I was taught - and I suspect this is what most people are referring to - to lift by the valves themselves. Essentially, this is using a split finger technique where the first finger is on one side of the valve neck 'T' and the second finger is on the other side. This seems to distribute the lifting force in such a way that the manifold is not torqued to any great extent (the upward force is primarily on the valve neck extension, not on the manifold side of the connection). Because the other finger (on the valve handle side of the 'T') is very close to the valve neck itself, there is less of a chance of bending the the metal valve stem by putting upward force on the handle.

Having said this, as one of the OTD / STDOT types, I find that I can still lift my double 80s with one hand around the manifold (close to/including the valve), and it doesn't seem to adversely affect the integrity of the manifold. It is no longer an issue with double steels - they are too heavy for me to now lift with one hand anyway.

I have also used the 'rope around the valve' technique with success, at least for short carries. But, for any situation where I have to move a set of steel doubles any distance, or up or down a ladder, I find the easiest thing - if I don't have a second person to help carry them or a hand truck - is to attach my BP and carry them on my back.

 

[halocline]

I believe the argument about whether or not the isolator should move freely when installed is not clear in this thread. When installing, it should be free to move slightly when the bands are tight; this ensures that it's not binding. With tight bands, mine can maybe move a third to a half of a turn. The problem I just encountered putting my doubles back together after VIP is that the free 1/3-1/2 turn is not in the range where I want the isolator valve to be pointing, if that makes sense. I messed a little with the bands and got it acceptable.

I agree that using the locknuts to hold it in place while in use is a good idea, but I would not be concerned about the o-rings. There are three on each side, and the tiny bit of movement is not going to cause failure. I very lightly lube those o-rings with Christolube.

But, the problem with leaving it freely moving is that the more you move it around the more you're likely to stress the threads (actually the whole manifold) given the small range of movement. And, maybe I'm being a bit overcautious, but I think you want that isolator valve in exactly the same place every time you dive; if you need to use it, you have to act fast!

 

[duckbill]

I think just in case, I will try to use other methods than lifting by the manifold. Given it is new and shiny and I don't want it to break too soon!

The crossbar is much more likely to bend quite a bit before it would ever break. I've seen lots of bent crossbars. I think it's obvious, though, that whatever you can do to minimize the stress you put on the crossbar is the best way to go. It has to be the weak link to the system.