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View Full Version : re-valve tanks OR convert my reg?!?



Byte Me
10-06-2008, 11:16
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

http://i161.photobucket.com/albums/t226/byteme45/stuff%20for%20sale/DSC_0007.jpg

http://i161.photobucket.com/albums/t226/byteme45/stuff%20for%20sale/DSC_0002.jpg

turnpikemike
10-06-2008, 12:04
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
10-06-2008, 12:23
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
10-06-2008, 12:23
This (http://www.leisurepro.com/Prod/CategoryID_976/Context_974/Sort_Stock/DescSort_0/Filter_6%3d526/MRSDAMR12.html?Hit=1) 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 (http://www.scubatoys.com/store/detail.asp?product_id=XS_Scuba_Tank_Valve), 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
10-06-2008, 13:15
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.


This (http://www.leisurepro.com/Prod/CategoryID_976/Context_974/Sort_Stock/DescSort_0/Filter_6%3d526/MRSDAMR12.html?Hit=1) 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 (http://www.scubatoys.com/store/detail.asp?product_id=XS_Scuba_Tank_Valve), 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
10-06-2008, 13:59
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
10-06-2008, 14:09
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
10-06-2008, 17:10
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
10-06-2008, 18:08
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.

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
10-06-2008, 21:58
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.

Byte Me
10-07-2008, 08:45
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.

No worries, this was never an option. As learned in rescue - modifying equipment to perform in a manner other than what was intended or engineered for it is one of the best ways to end up in need of rescue or worse, recovery.

I'm going to convert to DIN and get an adapter for warm water dives where yoke is status quo.

Jack Hammer
10-07-2008, 09:22
Try calling Northeast Scuba, they carry a lot of used/rebuilt valves. See if they have a 3/4" 200 bar din valve then spend $15 and add the convertable yoke piece to it. I believe there were 200bar din valves made in 3/4" at some point. That'd be cheaper and give you more options than just changing your reg.

Jack

awap
10-07-2008, 10:11
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.

I'm not joking. It may be a viable, affordable option which would allow this older valve design to be used with modern yoke regulators. I was hoping to see someone come along with some regulatory reason this is not doable. Or perhaps you could add some meat to your claim that there is "good reason nonetherless".

Exactly where do you think that magic catastrophic value is between 3442 psi and 3500 psi? And how is it that you think someone would be hurt? When you mount a yoke regulator on a tank with more pressure than the yoke can handle, you can expect the o-ring to extrude and leak or, perhaps the yoke to distort enough to result in a leak.

Here is a related discussion on Scubaboard: Using 232 bar yoke on HP 130 steel tank - ScubaBoard (http://www.scubaboard.com/forums/regulators/214570-using-232-bar-yoke-hp-130-steel-tank.html)

BSea
10-07-2008, 10:53
Try calling Northeast Scuba, they carry a lot of used/rebuilt valves. See if they have a 3/4" 200 bar din valve then spend $15 and add the convertable yoke piece to it. I believe there were 200bar din valves made in 3/4" at some point. That'd be cheaper and give you more options than just changing your reg.

JackAs mentioned earlier by Indydiver. The threads on those tanks are 7/8 USF not the 3/4 NPS that are the norm for most all scuba tanks today. Switching to the convertible valve is not an option.



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.

I'm not joking. It may be a viable, affordable option which would allow this older valve design to be used with modern yoke regulators. I was hoping to see someone come along with some regulatory reason this is not doable. Or perhaps you could add some meat to your claim that there is "good reason nonetherless".

Exactly where do you think that magic catastrophic value is between 3442 psi and 3500 psi? And how is it that you think someone would be hurt? When you mount a yoke regulator on a tank with more pressure than the yoke can handle, you can expect the o-ring to extrude and leak or, perhaps the yoke to distort enough to result in a leak.

Here is a related discussion on Scubaboard: Using 232 bar yoke on HP 130 steel tank - ScubaBoard (http://www.scubaboard.com/forums/regulators/214570-using-232-bar-yoke-hp-130-steel-tank.html)I see where you were going with cutting down the valve. And I agree that the pressure difference between the 2 is virtually non-existant. I know I've had just over 3500 in my hp120 that's rated for 3442. Most gages I've seen are + or - 2% or higher. So that gives more than a 68 psi high low range when filling a 3442 tank, or just over 3500 PSI when taking in the error factor.

And I agree that if done right, that cutting down the valve doesn't really expose the diver to any additional risk. But I also agree with Compudude (although I think the "Shame On You" was a little harsh). I wouldn't ever tell someone to do that in any public forum. 1st off, how many divers actually know the difference between a 200 bar valve & a 300 bar valve? My guess would be less than 10%.

Actually, since I know that those valves are hard to replace, I'd be afraid that the machine shop might ruin the valve. Then I'd have to find another one. As you and almost everyone esle pointed out, and the OP agrees. Converting the reg to yoke is the best, and arguably the only option.

IndyDiver
10-07-2008, 11:27
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.


I'm not joking. It may be a viable, affordable option which would allow this older valve design to be used with modern yoke regulators. I was hoping to see someone come along with some regulatory reason this is not doable. Or perhaps you could add some meat to your claim that there is "good reason nonetherless".


I see two issues here: 1. is it OK from an engineering point of view? 2. is it OK from a practical point of view.

1. It is fine from an engineering point of view. It is an easy thing to do with a good milling machine. Putting 3500 lbs of pressure on a 5 thread DIN valve is no problem at all, it is well below the rated working pressure of the 5 thread DIN standard. Yoke valves are used on 3442 tanks all the time and there is no real difference between 3442 and 3500 psi. If you are going to worry about things like that, start worrying that a yoke fitting is rated at 232 bar, which is only 3365 psi, and people are putting them on 3442 psi tanks with the manufacturers blessing.

2. It has problems from the practical side. Many shops will know that a conversion valve was never made in 7/8 thread, especially with the Genesis brand stamped on it. When they ask about it and you tell them, "I just milled 5mm off the front", they will not fill the tank for you. If the machine shop messes up the valve, you are out one hard/costly to replace valve. Finally, depending on your reg, the Yoke/DIN conversion may not be a big deal and may not need a converter when traveling. I have a Zeagle reg and to convert it from DIN to Yoke or vice versa, all I have to do is screw out one bolt that holds the fitting. It is no harder than screwing the converter on and off. If you start with a Zeagle yoke reg, the DIN fitting is $45. I don't think you can beat $45 by milling the valve and doing a new viz on the tank.

Finally, I would not recommend it on an open internet forum because I wouldn't have control of the machining operation. Given my low opinion of my fellow man's ability not to screw up even simple directions, I would not want to assume they wouldn't find some way to kill themselves doing the mods. (Leaving all the metal filings from the machining operation in the valve comes to mind)

All rebuttals are welcome:smilie40:

Jack Hammer
10-07-2008, 14:57
Try calling Northeast Scuba, they carry a lot of used/rebuilt valves. See if they have a 3/4" 200 bar din valve then spend $15 and add the convertable yoke piece to it. I believe there were 200bar din valves made in 3/4" at some point. That'd be cheaper and give you more options than just changing your reg.

JackAs mentioned earlier by Indydiver. The threads on those tanks are 7/8 USF not the 3/4 NPS that are the norm for most all scuba tanks today. Switching to the convertible valve is not an option.

...
Brain fart. I actually read the post regarding thread size and somehow confused the two. Good catch.

On a similar note, anyone know how difficult/costly/realistic it would be to have a 300 bar screw in din to yoke adapter made by a machine shop?

Jack

EDIT: I'm on a roll today, 2nd brain fart. Doesn't matter if they can make the adapter as most yoke regulators aren't large enough to fit over a 300 Bar din valve.

northfrisian
10-07-2008, 15:58
EDIT: I'm on a roll today, 2nd brain fart. Doesn't matter if they can make the adapter as most yoke regulators aren't large enough to fit over a 300 Bar din valve.

And even if it did, the valve does not have the dimple on the back that the yoke needs

Daddy Diver
10-12-2008, 15:04
There is a style of adapter that would work. Rather than the insert type which works on the convertable valves, a simple nipple design, with din threads on one side and a yoke on the other would work great. I've seen them for sale on ebay, cheaper than covnerting your reg and you can still do yoke

CompuDude
10-12-2008, 15:35
There is a style of adapter that would work. Rather than the insert type which works on the convertable valves, a simple nipple design, with din threads on one side and a yoke on the other would work great. I've seen them for sale on ebay, cheaper than covnerting your reg and you can still do yoke

If you're referring to these, they're are only for filling... not intended for underwater use. (And strongly recommended against.)

http://nuvair.com/shopsite_sc/store/html/media/A101.jpg

beperkins
10-15-2008, 11:20
The scuba gods were truly smiling upon you. You got a whole basement full of steel tanks, buying a DIN reg is a price I would pay gladly.