Yet another "What tank to buy?" question

[newton]

Originally posted by devjr
Nate, I think your dive shop misunderstood what you were asking. When you mentioned 300 bar the shop employee probably thought that you were requesting a 4500 psi air fill or perhaps a Nitrox fill.

Actually, I just said 'DIN valve'. No mention of pressure of anything else.

They had bad experience from another person who attempted to use LP steel tanks and DIN adapters in the past, and based on the hassle factor, don't want to even mess with it.

In the 15 years they've been selling dive gear, I'm only the second person who has even brought up the use of DIN valves, so they obviously aren't seeing a big demand.

None of the LDS has Nitrox either, simply because of the hassle factor. Interestingly enough, the one shop (PADI instructor) dives Nitrox exclusively when she is away from her, but does not have it here.

When I asked her about this, she said the cost and safety issues, along with the lack of deman made it prohibitive.

My conclusions are that Montana is NOT a scuba-diving mecca. ;-0

I've hardly met another diver who has any interest in examining how a valve works. Like you, I do, and I looked at some valves in detail.

I must confess to not being quite as thorough as you in examing the valves. I'm also convinced that DIN *is* a better solution than Yoke. In my limited experience, I've seen O-rings blow violently at surface. This happened on an older Sherwood valve, but that valve is virtually identical to the brand-new Sherwood valve I got on a new tank. (Thankfully, this happened on the surface..)

Based on the above and comparing it to a DIN connection, I believe that DIN valves (regardless of pressure) are significantly safer than Yoke valves.

Who needs DIN valves?

To answer my own question, divers who are worried about fishing line entangling the yoke screw. Also, cave divers who have 5000 psi in their tanks and bump their heads a lot.

DIN valves are OK, so are yoke valves. The differences are a matter of plumbing, getting the right part to fit the other part. The rest is theory.

I don't plan on bumping my head, but I have got stuff caught on the valve underwater (trivial to fix), as well as bumped the valve hard when un-pressurized on the surface that it unseated the 1st stage. I'm not sure that it would be that much harder to do pressurived, hence my interest in converting to DIN valves.

All that being said, I'm currently diving Yoke valves, simply because that's all I have. I'm not so concerned to go out and replace them right now, so this is more an excercise in seeing where my logic breaks down.

Apparently I'm either too pig-headed or stubborn to see the forest for the trees, since I haven't heard any significant risks why 300 Bar valves are better than 200 Bar valves.

The reason shown are valid, but I don't believe that the perceived risks are nearly as measurable/significant as they are purported to be.



Nate

 

[newton]

All I can say is that I'm glad we're on ScubaBoard, since otherwise I'd be called all sorts of names.

Originally posted by Uncle Pug

Uses LP jugs and....
300 bar DIN....
Go figure....

UP, you're losing your sublety here.

Let's do a cost/benefit analysis here.

For Omar and yourself, who pump your own gas and make sure *all* your equipment has DIN valves, there is no advantage to being able to use Yoke equipment. (Except perhaps, on vacation, but a simple DIN->Yoke adapter can be had easily, and that's a regulator issue, not a tank issue.)

So, without any advantage, why go with the 'inferior' valve?
Both of you believe that the 300 Bar is significantly safer than a 200 Bar valve, and all else being equal, it makes no sense NOT to use a 300 Bar valve.

Good for you. I on the other hand, based on my experiences with mechanical-type stuff and education, am not convinced that the safety issue is that large *ASSUMING* LP fills.

Given that constraint, I'm willing to assume the risk that Omar isn't willing to take with his high-risk valves. Basically, using DIN is a step-up from my current Yoke setup, regardless.

Based on my circumstances, his valves are a better than what I have now, where a 300 Bar valve are not a workable solution at this time.


Nate

 

[omar]

alright newton

Lets do that cost benefit evaluation:

200 BAR DIN/yoke manifold $199
300 Bar DIN manifold $215

200 BAR DIN/yoke valve w/insert $73
300 BAR DIN $80

Different brand valve
200 BAR DIN/yoke valve w/insert $58
300 BAR DIN $49
(yes these are the correct prices!)

200 BAR DIN/yoke manifold $179
300 Bar DIN manifold $179

Different brand valve
200 BAR DIN/yoke valve w/insert $51
300 BAR DIN $60

200 BAR DIN/yoke manifold $265
300 Bar DIN manifold $265

The marginal price difference for the 300 BAR DIN (only in some cases) does not justify the less than optimal gear configuration. This is tech diving, the primary concern here for me is to do it as safely as possible and come back. This means to find and use the optimal gear. The 200 BAR DIN is not it. Especially for my deco bottles it sure makes more sense to have the 300 BAR ftting instead of the 200. I also have been known to pump up my tanks so I want the DIN valves.

That is based on my experience as an engineer and a diver. We were just trying to save you some money up front but I guess that you need some more adult ed classes (that what I call my mistakes).

omar

 

[newton]

Originally posted by omar
alright newton

Lets do that cost benefit evaluation:

{ SNIP }

As my previous response stated:


For Omar and yourself, who pump your own gas and make sure *all* your equipment has DIN valves, there is no advantage to being able to use Yoke equipment. (Except perhaps, on vacation, but a simple DIN->Yoke adapter can be had easily, and that's a regulator issue, not a tank issue.)

So, without any advantage, why go with the 'inferior' valve? Both of you believe that the 300 Bar is significantly safer than a 200 Bar valve, and all else being equal, it makes no sense NOT to use a 300 Bar valve.


I assumed that the price between the two were mostly irrelevant.

The marginal price difference for the 300 BAR DIN (only in some cases) does not justify the less than optimal gear configuration.

And that's where we can agree to disagree. I don't consider the 200 Bar valves sub-optimal in the kinds of configuration I would use them in.

This is tech diving, the primary concern here for me is to do it as safely as possible and come back. This means to find and use the optimal gear. The 200 BAR DIN is not it.

And you're welcome to that opinion. As a matter of fact, if you don't believe the 200 Bar valves are safe, just believing that alone will make your dives less fun, since you'll be concerned about them, etc...

Especially for my deco bottles it sure makes more sense to have the 300 BAR ftting instead of the 200. I also have been known to pump up my tanks so I want the DIN valves.

And that's where we can agree to disagree again. I think it's MUCH more riskier to use LP tanks at higher pressures. Yet, this is extremely common with technical/cave divers, even those who claim to be 'Doing it Right'.

So, I'm willing to risk the chance of a 200 Bar valve failing, while you're willing to over-pressure your LP tanks. We're both taking risks that we believe are tolerable.

So, how much do you want to sell those inferior valves for? There obviously worthless to you, so I'll pay you what their worth.



Nate

ps. Boy, it's hard to get someone to sell you gear they aren't interested in around here.

 

[omar]

thermo 200 BAR DIN/yoke w/inserts, iso maanifold, AND plugs so you can use them as singles = $160 + ship

omar

 

[The Chairman]

Is that price for both valves? and who is the supplier?