Buying used manifolded doubles - considerations?

[rjgiddings]

I'm such a philistine...I read 'state of the tins' and my brain just couldn't comprehend ... it's early as I type this.

 

[flymolo]

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.

You can save a lot of money by bringing your own tanks to the hydro facility. It costs me 18 dollars a tank to get hydros done at the local fire safety place.

 

[Wibble]

You can save a lot of money by bringing your own tanks to the hydro facility. It costs me 18 dollars a tank to get hydros done at the local fire safety place.

That’s cheap! It’s 3 to 5 times that in the UK!

Mainly due to the IDEST cartel who certify the tanks. All well and good if you own one tank, not the 25ish tanks I have in the garage.

 

[halocline]

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.?

You might want to post what brand the tanks are, look up the buoyancy characteristics. There are older 3500 PSI tanks that have 300bar DIN valves with non-standard neck threads. The current 3442 PSI 'special exemption' tanks are probably what you want. They can use standard 3/4" valves and manifolds, and you can get those in either 200 bar convertible or 300 bar DIN. Either is fine. Here's a good article:

SCUBA Valves | Dive Gear Express®

SCUBA Valves Valves, Regulator Fittings, 200 vs 300 Bar FAQ, Cylinder Neck Openings

www.divegearexpress.com

Don't worry about the hydro cost, just make sure that if they need a hydro, the sale would be dependent on them passing. You can't look inside doubles without emptying and disassembling them completely. If you have any suspicion that they might be corroded inside, you could ask the owner to let you take everything apart, but then if you don't buy them, he's stuck with putting them back together and getting them filled.

There are lots of people that have used bands and manifolds around because so many divers have switched to sidemount. You might consider that. I have a pair of 7" bands I'd like to sell, they're heavy so shipping is not cheap.

 

[Lorenzoid]

I purchased all four of my steel doubles sets in used condition. Two of the sets hadn't been dived in a decade, yet were in great condition. Nevertheless, the seller agreed that the sale was contingent on them passing hydro and vis inspection. I wised up to requiring that condition after finding myself with rusty tanks in a previous transaction and having to persuade the seller to un-do the sale. Take them to a trusted dive shop and get their opinion of whether the tanks will pass hydro. In the case I mentioned, my trusted dive shop was dubious they would pass hydro due to too much rust.

As for bands, they seem to last forever and, as a previous poster said, easy to find used. On one occasion, when I bought a matched pair of tanks from a sidemount diver, the dive shop I took them to said they might have an old pair of bands lying around that they'd sell me.

 

[rob.mwpropane]

That’s cheap! It’s 3 to 5 times that in the UK!

Mainly due to the IDEST cartel who certify the tanks. All well and good if you own one tank, not the 25ish tanks I have in the garage.

Depending where I am willing to drive it's $11, $13, $25, or $35. None include fills.

So that's another good point. I have a compressor so breaking down doubles to hydro then putting them back together and filling myself isn't a big deal. If you have to have a shop fill them they'll want more for that scuba tax (VIP) to put them back together and then fill.. I'm not sure what that would be. It gets expensive, especially if the shop is O2 cleaning on top of everything else.

I purchased all four of my steel doubles sets in used condition. Two of the sets hadn't been dived in a decade, yet were in great condition. Nevertheless, the seller agreed that the sale was contingent on them passing hydro and vis inspection. I wised up to requiring that condition after finding myself with rusty tanks in a previous transaction and having to persuade the seller to un-do the sale. Take them to a trusted dive shop and get their opinion of whether the tanks will pass hydro. In the case I mentioned, my trusted dive shop was dubious they would pass hydro due to too much rust.

As for bands, they seem to last forever and, as a previous poster said, easy to find used. On one occasion, when I bought a matched pair of tanks from a sidemount diver, the dive shop I took them to said they might have an old pair of bands lying around that they'd sell me.

I haven't seen it, but a guy I oyster dive with has his own tumbler. He said even when they're pretty bad with rust he can tumble them and get them to pass. I think some shops just don't want to deal with the hassle and then have to charge someone for all that. Just easier to say no. VIP's are a quick buck, tumbling and actually working, not so much. (of course not all shops are like that).

 

[Lorenzoid]

I haven't seen it, but a guy I oyster dive with has his own tumbler. He said even when they're pretty bad with rust he can tumble them and get them to pass. I think some shops just don't want to deal with the hassle and then have to charge someone for all that. Just easier to say no. VIP's are a quick buck, tumbling and actually working, not so much. (of course not all shops are like that).

In the case I mentioned, the shop believed tumbling wouldn't remove the rust damage. They have tumbled other tanks I bought to remove flash rust. If it's just flash rust that can be removed with tumbling, I wouldn't hesitate to buy the tanks. The bottom line is I trust my shop. I'm not trained to do VIP.

 

[OTF]

There's nothing wrong with the narrow neck high pressure PST steels, some of them are excellent tanks. The issue is that finding a good price on a narrow-neck manifold can be difficult. If the tanks are already doubled and come with a manifold no problem.

 

[flymolo]

There's nothing wrong with the narrow neck high pressure PST steels, some of them are excellent tanks. The issue is that finding a good price on a narrow-neck manifold can be difficult. If the tanks are already doubled and come with a manifold no problem.

I agree there's nothing wrong with them, but finding a matched set of valves may be a problem

 

[rob.mwpropane]

In the case I mentioned, the shop believed tumbling wouldn't remove the rust damage. They have tumbled other tanks I bought to remove flash rust. If it's just flash rust that can be removed with tumbling, I wouldn't hesitate to buy the tanks. The bottom line is I trust my shop. I'm not trained to do VIP.

I'm not sure what you did there, that's what I typed buy it looks like you quoted someone else?

At any rate, he said that the shop condemned the VIP on an LP108 (at least I think that's the size) and he got a hold of it and tumbled it. Took it to the hydro shop himself and it passed. He said it was very bad inside, but after a long tumble all was fine.

All I'm saying is just because it looks really bad it might be salvageable.

There's nothing wrong with the narrow neck high pressure PST steels, some of them are excellent tanks. The issue is that finding a good price on a narrow-neck manifold can be difficult. If the tanks are already doubled and come with a manifold no problem.

I agree... unless you're the one cleaning them. I own 6 sets of PST doubles and they're a little bit of a pain. Well worth the deal that I got on them though so I'll make do.