Making a doubles system

[Essroc123]

How difficult is it to make a doubles system?

I have been looking at prices on the net, and a turnkey solution runs around the $1500 cdn mark! That is a lot of money. Is there something that can be done for less dough, and still be safe?

Safe Dives,

Will Johnson

 

[strider]

Doubles aren't too difficult to set up and you will need to put them together at the dive shop anyway to get them vip'd when you put them together. This is where one part can get tricky, if you don't have a decent relationship with the shop they sometimes get upset if you bring in a manifold, set of tanks and set of bands you bought somewhere else. I would recommend buying atleast one piece from the shop and definately check to see what prices or package deal they can make you. If you dive a lot ask for a couple air fill cards for buying the whole package or something, valuable to you but doesn't cost them much. Check leisurepro.com for good prices, I have ordered a lot through them and they are very good to work with. Shipping on tanks can be very pricy though, so that may be something to buy locally.
You need 2 matching tanks, a manifold and a set of bands. I really like the rotation cross bar manifolds since they are adjustable as far as tank spacing and can't be knocked loose. As far as what specifically to buy it will depend on how you feel about things, ie., isolation or not. Read the posts and research. I personally love OMS gear, especially as far as the more tekkie stuff goes and tanks.
Good luck,
Justin

 

[strider]

You know what, I didn't really realize that you meant actually fabricate a doubles set up.
I would say very hard, but there is something I have thought about and if you're not doing it for the redundancy or safety factor, it may work.
If you had a small high pressure hose made up with 7/16" *20 threads and o-ring sealed ( have a dive shop make a high pressure hose with reg fittings on it) you could run it between the hi pressure ports on 2 first stages. You would need one first stage to have 2 hi pressure ports, but only one would need the gauge. I wouldn't do this with yoke fittings, as you're just asking for trouble, but if they were both DIN you may be allright, You would need a way to twin the tanks, hold them together, like the softband systems or ss bands. bands are relatively cheap, and by the time you bought 4 cam bands to create your own you might as well just buy the bands ready made.
You may also want to consider independent doubles, which I've dove a lot and aren't that bad, great redundancy.

 

[Essroc123]

Strider,

Actually I am glad that you posted the tips outlining both. The fact of the matter is that I want to be as safe as possible, but at the same time understanding that money does not grow on trees.

The LDS that I am going to be buying some of my stuff from seems to want to give me good value for the money that I am going to have to spend.

But thanks for the tips Strider!!!!

Will Johnson

 

[Groundhog246]

IF you have the tools to work with s/s, I wouldn't think fabricating a set of bands would be particularly difficult. I've certainly made more complex and just as critical pieces for my boat.
I watched a service guy re-assemble a just oxy cleaned manifold, then re-assemble the doubles set. I can't see trying to manufacture your own isolation manifold. It would be a lot of machining and fitting (do you own a high tolerance metal lathe?). And the consequences if it failed would be huge (especially if you were wearing them when they failed).

 

[BlueDevil]

Certainly don't overlook the option of independent doubles. Setup cost will be less, and you still have the option of using your tanks as singles when you want. There is a range of arguments as to the relative safety of independent vs manifolded doubles, with both options having their good and bad points. The manifolded doubles proponents tend to be more vocal than the independent doubles proponents, but this doesn't necessarily make them better than the other. Ultimately you have to make a decision based on what you are comfortable with for the type of diving you are doing.

BD

 

[unfix8r]

I am going doubles, too. If you check my thread I was looking for plans... someone came up with them.

The manifold seems to be to one sticking point. DIR guys say there's only one way, of course. I am making my own doubles setup as we speak and will post it upon completion.