Buying used manifolded doubles - considerations?

[Mr. Dooley]

Looking for HP 100 manifolded doubles. Found a used set I'm going to check out.

I've never owned doubles. Just curious if there's anything in particular I should check out / consider? For the cylinders themselves of course I'll review VIP / hydro status, the valves themselves are what I need (DIN), etc.

Are tank bands more or less universally compatible with a standard BP/W setup? Anything I should be considerate of pertaining to damage / corrosion unique to bands / manifolds, etc.?

 

[tbone1004]

bands are universal, Dive Rite set the band spacing 30+ years ago, but they can move up and down on the tanks so that's a non issue.
Pretty much all manifolds will be DIN, exceedingly rare will you see a yoke only manifold.
Check corrosion under the bands and under the boots if they have them on. If not then you are good to go.

 

[inquis]

How difficult is it to close the valves? You may wish to get them rebuilt if not "thumb & index finger easy". (Or a haggle opportunity.)

 

[2stroketony]

Insure you get the right size bands for the tanks you will use. Insure your bc can handle the extra weight and have you considered running independent doubles and staying with two separate valves and running two 1st stages.

 

[rob.mwpropane]

I would figure what it would cost to rebuild the valves, to hydro, and to VIP... total up what you're really looking at.

3/4" neck would be preffered and double barrel o ring manifold also preferred. 3" bands preferred, but not an absolute. I would use all that to haggle the price or at least let that dictate what I'm willing to pay.

Just for reference my last set of doubles was $40 to hydro and $30 in parts to completely rebuild the valves. If a used set still had a good amount of hydro left and the valves felt great I'd of been willing to pay more than I did.

@tbone1004 said it, but I loosened the band and checked, popped the boots off and checked, and took a wrench and did a quick and dirty tap on the side. If there's a thud (which I have yet to hear) then there's supposedly some crap in there. If it's a nice echo ting then they "should" be ok inside. I haven't come across a dirty rusty tank yet, so I don't know how accurate that is.

Maybe try smelling the gas? I don't know what else.

If you plan to do all that make sure you show up with a whip or pressure checker so you're not blowing gas all over the place opening valves. Bring your own tools ready to go. I can get away with two adjustables and a tank checker.

 

[Scared Silly]

Bands are universal in that they should have the same spacing for the manifold but not universally the same quality.

 

[flymolo]

Try to avoid the captive o-ring manifolds, angled valves, or thin tank necks found on some older PST tanks.

 

[Jimchris]

Try to avoid the captive o-ring manifolds, angled valves, or thin tank necks found on some older PST tanks.

Nothing wrong with the older face seal OMS manifolds (I have several, of which a couple have been knocked around hard in the back of the truck w/o issue), internal parts are identical to current blue steel branded (SanoSub built) valves, burst disks are just not as readily available, though I think A Plus Marine still stocks high pressure disks and the accompanying washer.

 

[rob.mwpropane]

Nothing wrong with the older face seal OMS manifolds (I have several, of which a couple have been knocked around hard in the back of the truck w/o issue), internal parts are identical to current blue steel branded (SanoSub built) valves, burst disks are just not as readily available, though I think A Plus Marine still stocks high pressure disks and the accompanying washer.

John @ NESS does too. I didn't know Aplus did, so thanks.

My set leaked. Showed up to a dive with 1/2 my gas gone. I could of probably gotten away with just changing the face o ring but I went ahead and rebuilt everything. Smooth as butter now.

 

[Wibble]

Are they in test? Are they oxygen cleaned? Both of those are "expensive".

I'd look for a twinset that's in test. If it's recent, last 6 months, even better. The state of the tins really doesn't matter as it's just cosmetic.

You don't want boots on the cylinders as this hides rust. Bare metal's fine as the bottom's scraped around. You must store them in a dry place.


If the tests are due soon, you need to budget for 2X test price plus a fee for breaking down the cylinders. In the UK this is circa $180 (£110). Obviously this sets the maximum price you should pay.