Is this pair of OMS steel 85's a deal worth jumping on?

[84CJ7]

Semi locally (about an hour each way) there is a pair of OMS 85 LP steel tanks for sale set up in a doubles configuration with the steel tank bands and the doubles manifold (listed as 2400 PSI DIN convertible to yoke).
The person is asking $275 and the tanks look to have been made in 98 and 99 and last stamped hydro date I can see in the pictures is 04+ and 09+ (I think). They have some sort of grey external finish which is scuffed off in a few places (normal use wear).
The person is guaranteeing a refund if they don't pass hydro (probably not legally binding) and I would take everything off and look inside each for rust first (light flash rust is OK I was told). They have apparently been stored in a closet and at the moment don't have air in them (no details on if that was just for inspection now or long term).

Assuming there is no internal rust issues is this a good enough deal that I should really jump on it? I don't actually need the double setup yet though I would like to do that eventually, but I do need two matched steel tanks for singles diving and that is about the size I want too. These don't look like the doubles tank valves that can be DIN plugged to work as singles so I would likely be looking at different tank valves entirely for now on top of everything else.

I often see people quote comically low numbers for what tanks "should" cost, but there is very little for sale around where I live and what little is for sale in steel is normally far more expensive and sold quickly.

What else do I need to know to not get hosed if I do this?

 

[Wookie]

I recently sold 2 sets for $650 per set. That doesn't speak to your deal, but it seems like a heck of a deal to me.

 

[bamafan]

Sounds like a good price. If they have the stupid boots still on the tank I would remove them and check under them for rust before buying the tanks. Fabers / OMS tanks are bad about rusting under the boots if they are left on the tanks. You are a good ways from salt water so it might not be a problem. If the owner will let you break them down you can buy a cheap light from an auto parts store that has a small flexible single led head on it and look inside the tanks.

 

[84CJ7]

I just sent him a message asking him to look inside for rust to save me the drive, but I told him I will also internally inspect them when I get there. They do not have tank boots.
I actually have a little single LED flex light that when you pull the hood off the LED is perfect for this sort of inspection. I have used it to look into motorcycle cylinders through the spark plug hole before.
It is highly likely they they were sold immediately and he just hasn't pulled the ad down though.

EDIT: The ad was apparently just put up and it looks like I am buying them and picking them up later tonight.
Just to display my ignorance this isn't one of the brands that has the oddball "round out" hydro test is it? I'm not even sure who actually manufactured these even if OMS is the brand, I will have some homework when I get home.

 

[Scared Silly]

OMS cylinders are actually made by Faber. The round out test is for PST cylinders. These are fine cylinders, we own a set of OMS LP66 cylinders. Yeah the gray paint wears a bit but nothing to worry about. About the only comment is on the manifold. OMS manifolds are face sealing whereas barrel seals are more common. Some people like them some do not. If these are your only set of doubles then nothing to worry about (especially given the price). Enjoy as even shelling out for hydro they are good deal. Note the REE is on the cylinder make sure the hydro facility runs the numbers for the plus rating.

 

[84CJ7]

OK, back with the prize. Looking inside they mostly look brand new except for random surface rust spots like someone flicked water at a sheet of metal with wet hands. I don't see any pitting or deep looking specs but they may need a tumbling with the VIP but should be good. The last hydro dates were 09+ and 08+ (not 04 like I thought) so they will be going in immediately.

He gave me the boots with the tanks, though he said he doesn't use them anymore. I got the original OMS brand tank valves which are DIN with yoke inserts. The tank bands are a brand called highland and seem to be super sturdy stainless. If thermo is a brand then they are the ones who made the 2400 PSI DIN doubles manifold which also came with 4 steel plugs with double O rings (sitting on bag, one hidden) to convert them to singles maybe or some other purpose I am not aware of.
He also accidentally gave me the original sales receipt which shows he paid $704.97 for the 2 tanks, the manifold and the bands in mid 2006. I think he got the tanks used or cheap because they were $379.98 for just the 2 tanks both of which were already 7 or 8 years old at the time judging by the 98&99 manufacture and original hydro dates. In short I am thrilled to have such expensive useful gear at this price, glad I jumped on it. I didn't even use very much gas getting there and back.

Some questions:
Concerning service, I will use these as singles so I will be putting the OMS valves back on and storing the bands and doubles manifold set until my diving reaches that level. I assume I should be having the tank valves checked out with new all O rings when the inspections and tank service is done?
Do they tumble tanks for light rust droplet spots or is that considered normal and ignored, or do they leave it up to me? I would rather have it done, or maybe I should figure out how to do it myself, I know there are threads on that, but I need these ready to go fast so maybe I should let them do it if its cheap (is it?).

The stuff on the tanks is somewhat hard to read because Faber painted over the stampings pretty thoroughly and some of those stampings weren't quite so thorough. How do I identify which exact set of tanks these are to see specifications on buoyancy and what not. The receipt says E7-LP 85 but I assume that's the shops generic code for these size tanks.

 

[Scared Silly]

The rust spots can be removed with a light whipping. I would not worry about them until the hydro is done. The Highland bands are made by XS Scuba who bought the name from Joe McGrath (RIP). Good bands. Same with manifold, Thermo. It looks like you also got the plugs for the left and right valves. You can insert them an not use the OMS valves. Either will work. But yes you should have the valves serviced. As for the cylinder marking, some folks use a Sharpie to mark the letters and numbers.

All in all I would say you got a great deal.

 

[claymore]

This sounds like the deal I got on some OMS tanks this winter. I got a pair of OMS 98's with bands and OMS valves and manifold for $90. Split the tanks sold the bands and manifolds put on new Thermo modular valves and probably broke even on the deal.

From personal preference stand point I would plug and leave the Thermo valves on. The manifold extension on the side makes the tank a lot easier to carry.

 

[84CJ7]

Just to have the knobs on the same side and avoid the extra O rings and whatnot I am going to use the single OMS valves because I won't need the doubles for a long while. There is enough there for me to easily grip one handed.

I just drove an hour to the tank place (not dive shop place) that all the dive shops around here take their tanks to and for $33 each they will get +rating hydro tested, internally shot blasted to remove the rust spots and anything else and then visual inspected with a sticker applied.
The dive shops REALLY screw us on prices it seems. Most wanted at least double that to do the same work and many didn't do cleaning at all.

The guy at the testing place was a bit of a pessimist I think because he said "everybody" overfills the steel tanks to 3000 PSI and then "most steel tanks" fail when brought in and he wanted to warn me ahead of time that might be the case. I highly doubt it as the doubles manifolds clearly say 2400psi on each one and the previous owner said he usually was irritated by 2200 psi under fills by the time he was at the water.
I think I will be sure to specify to the person filling that I want a slow fill to 2640 with a 2nd top off if needed rather than an overpressure to account for cooling and I don't care how much extra it costs me or how long it takes. I need these tanks to last forever, I am too poor to do this twice.
In fact I think I will write "2640 PSI MAX" on the top of each tank with a black sharpie when they get back. I do like belt and suspenders idiot proofing things as often as possible.

On that note:
1. How would a person get the tanks plus filled to 2640 with the valves on the double manifold that say 2400 psi on them? Do the shops ignore this? The singles valves do not have a rating on them. Maybe that was why he always got a short fill, they stopped at 2400 and he didn't get them topped off.

2. Why does this daffy bastard industry rate a steel tank at 85 for size, but then rate the tank at a standard pressure that would make it about a 76.5? Why call it "plus" if the rated capacity means that is intended to be standard? I am told this is not done with aluminum or some steels.

And an interesting side note, the guy who runs the place said that the "round out" procedure for PST tanks doesn't follow DOT guidelines so he either doesn't test those or fails most of them, I didn't really ask which.
He did say he has had scuba manufacturers arguing with him about their tanks.
I did get the impression that non dive shop hydro testing places (pretty much all there is here) consider scuba to be something of a bother over regular testing of tanks.

 

[Scared Silly]

1. How would a person get the tanks plus filled to 2640 with the valves on the double manifold that say 2400 psi on them? Do the shops ignore this? The singles valves do not have a rating on them. Maybe that was why he always got a short fill, they stopped at 2400 and he didn't get them topped off.

Sometimes ya got to educate the fill monkey. The rating on the valves has to with burst disk which is related to the base 2400 psi fill.

2. Why does this daffy bastard industry rate a steel tank at 85 for size, but then rate the tank at a standard pressure that would make it about a 76.5? Why call it "plus" if the rated capacity means that is intended to be standard? I am told this is not done with aluminum or some steels.

The plus rating is a by product of WWII.

And an interesting side note, the guy who runs the place said that the "round out" procedure for PST tanks doesn't follow DOT guidelines so he either doesn't test those or fails most of them, I didn't really ask which.
He did say he has had scuba manufacturers arguing with him about their tanks.
I did get the impression that non dive shop hydro testing places (pretty much all there is here) consider scuba to be something of a bother over regular testing of tanks.

When he fails a cylinder without doing the round out and the owner is knowledgable about the round out and that it was not done and he gets a summons to small claims court to replace the cylinder he might change his tune - otherwise thank him for being forthright as you will make sure to use another facility that can follow instructions.