OP
Steel tank questions
- Thread starter BigRed96
- Start date
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OP
BigRed96
Contributor
2airishuman
Contributor
You may find that gentle heat helps to remove the vinyl. I put one in the oven once. Heat guns also help. Elbow grease still required.
I have the cylinders hydroed before investing time and money in them. Some fail
Older valves are subject to a variety of maladies and I've started just replacing them since I am not interested in vintage diving but rather just getting a good cylinder at a reasonable price. I have tried to fix up several J-valves and find that they are prone to leakage. Many J-valve designs leave the reserve mechanism pressurized even when the valve is off so an otherwise inconsequential stem leak will drain the cylinder after a month. Parts availability for the J mechanisms is poor. I have a Calypso J regulator that I can use to experiment with when I want to dive with a J reserve that doesn't require me to have a dedicated cylinder.
Replace the burst disc assemblies with modern ones, the single port ones are unsafe. The correct burst disc is 3750 PSI, some shops still have these but I have not found a source that ships nationwide. Some people use 4000 PSI burst discs since those are readily available, even though it is technically a violation of the CFRs
Vintage manifolds are picky about cylinder spacing and even back in the day were not particularly reliable. Whether it makes sense to double these up depends on your dive goals. I have a doubled pair of LP72s with a modern manifold. I do use them occasionally for deep solo dives although in most cases I will take a pair of HP100s instead. Or an HP120 and a pony which is more or less equivalent gas wise, and lighter.
It is hard to find modern bands for LP72s though they do exist.
I like LP72s and have around 10 of them. I like the neutral buoyancy. They are inexpensive - usually I pay $30 as-found, as-is, where-is. With hydro, VIP, and a new valve it's a $100 cylinder. Low cost is part of the attraction; generally I'd rather have HP100s but when comparing ready-to-dive prices they are 2x-3x as much (used).
I have the cylinders hydroed before investing time and money in them. Some fail
Older valves are subject to a variety of maladies and I've started just replacing them since I am not interested in vintage diving but rather just getting a good cylinder at a reasonable price. I have tried to fix up several J-valves and find that they are prone to leakage. Many J-valve designs leave the reserve mechanism pressurized even when the valve is off so an otherwise inconsequential stem leak will drain the cylinder after a month. Parts availability for the J mechanisms is poor. I have a Calypso J regulator that I can use to experiment with when I want to dive with a J reserve that doesn't require me to have a dedicated cylinder.
Replace the burst disc assemblies with modern ones, the single port ones are unsafe. The correct burst disc is 3750 PSI, some shops still have these but I have not found a source that ships nationwide. Some people use 4000 PSI burst discs since those are readily available, even though it is technically a violation of the CFRs
Vintage manifolds are picky about cylinder spacing and even back in the day were not particularly reliable. Whether it makes sense to double these up depends on your dive goals. I have a doubled pair of LP72s with a modern manifold. I do use them occasionally for deep solo dives although in most cases I will take a pair of HP100s instead. Or an HP120 and a pony which is more or less equivalent gas wise, and lighter.
It is hard to find modern bands for LP72s though they do exist.
I like LP72s and have around 10 of them. I like the neutral buoyancy. They are inexpensive - usually I pay $30 as-found, as-is, where-is. With hydro, VIP, and a new valve it's a $100 cylinder. Low cost is part of the attraction; generally I'd rather have HP100s but when comparing ready-to-dive prices they are 2x-3x as much (used).
We occasionally used compressed air and an air gun to "inflate" the vinyl. It helped in pulling the coating away from the tank. We just inserted the air gun into a hole or cut in the coating and applied the air pressure. Sometimes it worked, sometimes not, but when it did it eliminated allot of elbow grease for that portion of the tank.
Bob DBF
Contributor
If one gets lucky, Sherwood made a manifold (Selpac) for double hose with an additional post, and shut off valve, for a single hose backup. The one I scored did not have one, but they did make them with the j valve. It was probably the last old school manifold made before the modern isolation manifold became the standard.
whether they match the spacing on a vintage single outlet manifold is anyone's guess.
6.7 to 7.00 Inch Stainless Steel Cylinder Bands w/ Protective Rubber Padding
captain
Contributor
captain
Contributor
Bob DBF
Contributor
Since the OP is interested in vintage , he may want to keep his eye out for some old galvanized bands used originally.
Double 72s
OP
BigRed96
Contributor
So, after figuring out what manifold a guy wants to use ( in my case I’m going to go with the US Divers with J valve) how does one figure out which bands to get as far as spacing goes? I know that 72s are 6.9” but have heard that 7” will work.
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