re-valve tanks OR convert my reg?!?

[Byte Me]

I've been thinking about picking up a couple steel 100's for myself. Mentioned this to a friend who said "my dad used to work at a place that made them, we've got a bunch in our basement that I'm sure he'd sell." SWEET! was my first though. A great deal on steel 100's! I picked them up from him and other than needing vis and hydro, which I expected, they're also DIN. I've got a Delta IV / FDX10 reg which I'm told could be "converted" to DIN. If I did this I'd get a yoke / din adapter for travel diving purposes since most are yoke. Tanks are in very good condition and have had air in them the whole time they've been in his basement.

My other option, which my LDS said would be the preferred route - is to re-valve the tanks to DIN but w/ yoke inserts. Current valves are Sherwood 6300 DIN. Trouble is I have no idea what valves I'd need. They did mention I'd probably have to find them used or new old stock since they don't make them new any longer for this type of tank neck?!?

So, I'm hoping for two things here -

1: Do I revalve or convert the reg?
2: What valves would I need and where can I find them?

Thanks! Pictures of the tanks below:

Markings on the valve back are "4000 - 120" and "3500" then on the neck it's stamped G88

[turnpikemike]

I could be wrong on this, but I thought those were the same valves I had on the HP100's I got, and they said the DIN valves with yoke inserts wouldn't fit because the diameters were different (and I don't assume the LDS was lying, but maybe I misunderstood something). I had to switch the regulator to DIN.

[IndyDiver]

The old 3500psi tanks had 7/8 USF threads in the tank necks. All current convertible DIN/Yoke valves with inserts (Such as the Thermo "Pro" valve) have 3/4 NPS tank threads. There is no one that makes a convertable valve with a 7/8 thread.

[turnpikemike]

This is similar to what I had to buy (although they're regulator specific, make sure you're getting the right one) to convert my reg. The tank valve conversion method would probably be one of these, I think. But as far as I know, they only come in one size (which is different from these Sherwood 6300's, I believe).

[BSea]

Originally Posted by IndyDiver

The old 3500psi tanks had 7/8 USF threads in the tank necks. All current convertible DIN/Yoke valves with inserts (Such as the Thermo "Pro" valve) have 3/4 NPS tank threads. There is no one that makes a convertable valve with a 7/8 thread.

Originally Posted by turnpikemike

This is similar to what I had to buy (although they're regulator specific, make sure you're getting the right one) to convert my reg. The tank valve conversion method would probably be one of these, I think. But as far as I know, they only come in one size (which is different from these Sherwood 6300's, I believe).

IndyDiver is right on. You cannot use a newer valve with an insert. I also don't believe there ever was a yoke valve made for those tank threads. I believe your only option is to convert your reg. Just get yourself a yoke adapter for the times you use a regular yoke valve. And keep the yoke from your reg when the conversion is done, so you can switch it back to yoke when you go on an extended trip where all the tanks are yoke.

[awap]

I wonder what it would take to get a machine shop to cut 2 threads worth of thickness off the face of that valve? I does not look like it would be that hard. At 3500 psi, I don't believe there is a strength problem as much as a compatibility problem.

Of course, there could then be a problem getting fills with the modified valve. Maybe paint the valves black and explain that the chrome was scaring fish.

[Byte Me]

Thanks! Almost a year since I got the regs so back to ST for service, have them convert to DIN and get a DIN adapter for travel purposes. Appreciate the help!

[BSea]

Originally Posted by awap

I wonder what it would take to get a machine shop to cut 2 threads worth of thickness off the face of that valve? I does not look like it would be that hard. At 3500 psi, I don't believe there is a strength problem as much as a compatibility problem.

Of course, there could then be a problem getting fills with the modified valve. Maybe paint the valves black and explain that the chrome was scaring fish.

Am I missing something? Why cut the valve at all? It should work with almost all din regs out there. The conversion kit mentioned by turnpikemike was 300 bar, so that should work fine.

[awap]

Originally Posted by BSea

Am I missing something? Why cut the valve at all? It should work with almost all din regs out there. The conversion kit mentioned by turnpikemike was 300 bar, so that should work fine.

I believe that valve will only work with a 300 bar (7 thread) din connector. It will not work with the 200 bar (5 thread) din connector, Nor will it work with the screw in yoke adapter as the adapter is only available in the 5 thread length. And even is someone decided to make an a yoke adapter for 7 threads, the valve will still be too long for many yokes to fit over. But if the face of that valve were shortened the 2 extra threads, about 5mm, then the yoke adapter would work OK. And it would still accommodate either the 5 or 7 thread (200 or 300 bar) din connector. But, if your fill source realized what was done, they might balk at filling it.

The cleanest solution is to convert the reg to 300 bar din. And then you either convert back or use the din to yoke adapter for tanks with yoke valves. The 300 bar din connector stick out a bit further than the 200 bar connector but that should not be a problem until you add the yoke adapter and it gets another 1/4 inch or so closer to the back of your head.

[CompuDude]

You should be ashamed of yourself, awap. You should know better than to give advice like that. You're going to get someone seriously hurt... and yourself sued... one of these days with comments like that. It's one thing to joke among friends during your SI, it's another to present it as a seriously viable option in a public online forum where who knows who may be taking you seriously.

OP: Do NOT start hacking pieces off your valve. These are "true" high pressure tanks, 3500psi, which are required to be used with DIN only. (No, no one enforces this as "law", but there is good reason nontheless.)

Convert your regs to DIN, or pick up a second (DIN) first stage, if you want to use these tanks. DIN first stages can be had for $60 (new), less if yo buy used, so this is NOT a huge expense.