O2 reg suggestions

[normblitch]

I'm starting to make up a EAN100 pony for deco...

Looking for suggestions for a first stage that is:

Easily made 100% O2 safe,

Compatible with the low-performance DR 2nd stage, and

Often seen available used and reasonable...

(20' max depth use)

Thanks!
Norm

[Tegg]

Apeks DS4

[ARY]

Easily made 100% O2 safe,
Compatible with the low-performance DR 2nd stage, and


Norm, i use Oceanic CDX very simple yet small size first stage with DR second stage and pressure gauge type HPP plug. 02 cleaning for CDX was not a problem. Make sure you have LP hose long enough to route comfortably around your neck. I think i paid $80 for new CDX and $35 for gauge-plug.

I hope you are diving this weekend!


ARY having flu.

[Mike B.]

Look for a sherwood someone has laying around. Easy to work on,bulletproof performance, and cheap.

[John L.]

Any piston first stage would be easy to put into O2 service. Scubapro MK4, tusa, sherwood. Usually the entry level ones.

[crazyduck]

As a side note- US Divers is putting a “heat shield” in the 1st stage to stop with the heating processes of the first stage while using oxygen. I was recently advised that Air-liquide (SP) requires all US Divers/Aqualung products to pass the same testing process as their gas systems. I have not actually seen anything in print but if it is true then we have another barrier between the diver and the heating process and possible burning of oxygen.
When you look into the 1st stage on the legend you should see the metal plate with a series of holes that is the "heat shield."

Outside of that I agree that any simple piston 1st stage will probably work. Please keep the unit specifically for the O2 tank, and you need to clean the unit regularly and store in a clean enviroment. Hydrocarbon and debrie build up can lead to an ignition source. Also you would benefit from a DIN fitting over a yoke fitting.

Andrew

[normblitch]

Any piston first stage would be easy to put into O2 service. Scubapro MK4, tusa, sherwood. Usually the entry level ones.

(And Thanks to all for the ideas!)

The opinions amd PM's have generally split 50/50 between specific high-end products and general-use pisto 1st stagess...The "general-use pistons" crowd usually adds the caveat that O-rings "age" RAPIDLY with 100% mix...does this mean 6-months rebuilds with Moderate use?

Norm

[Genesis]

Depends.

If you use EPR (EPDM) O-rings, and you should, there should be no issues with regular service intervals. There can be issues with things like diaphrams though, as I've yet to see anyone be real clear about exactly what kind of material they're made of and how their lifetime is impacted by pure O2.

One thing that IS important is to dedicate the reg to pure O2. If you NEVER boost into your 100% tank, filling ONLY by transfilling from an O2 supply cylinder, there is never any contamination source that goes into the tank, valve - or your reg. This radically reduces the risk of an "event".

If you DO boost, then you have raised the bar considerably, because now there's a booster there that can cause contamination or "shed" particles that can become trouble. If you don't own the booster, then you've just added an unknown as you have no way to know when it was last torn down and overhauled or what kind of internal condition it is in. If you exchange the reg onto other tanks, ditto - as soon as you jack it on a tank that contains anything other than pure, gas-supplier-provided O2, you are introducing contamination. Even with a hyperfilter on the gas supply (which should be used IMHO on ALL breathing gas systems - and I'm well aware it often is not!) very small amounts of contamination do get through, and their impact is cumulative.

My personal protocol is that my O2 reg ONLY goes on my O2 bottle, and when not on that bottle is capped with a sealing delrin DIN cover. The O2 bottles themselves are dedicated to this service and never see anything other than a transfill off an O2 supply cylinder. I trust my gas supplier not to sell me a contaminated O2 tank, because odds are that if they did it would blow up in their facility - before I got my hands on it. This is easy for me to do, because I mix my own gas - this level of control is a LOT tougher if you BUY gas from a shop, because you have no control over the transfill whip used or how its handled (did the guy who used it last get finger oils on the DIN filler O-ring?) and, if they boost anywhere along the line (even from their supply to a storage tank) then the cleanliness issue is off the table.

If you can't maintain this level of control then I'd be tearing that reg, tank and valve down every six months and giving the valve and reg a good O2 cleaning in the Ultrasonic, plus giving the tank a good wash-out with Blue Gold.

I also like first stage regs for this purpose with nice, short, straight gas-paths internally with no convoluted places for gas to impinge on and cause adiabatic heating. IMHO simpler is better, and there's no point in a balanced design, since you can't breathe the O2 below 20' anyway. All the balanced design does is add twists and turns, along with nooks and crannies, to the gas path.

And, of course, always crack valves and fill O2 tanks S.L.O.W.L.Y.

There is no guarantee when it comes to O2 incidents. Be aware that despite the claims of "O2 compatability" nearly all seats used in regs today will indeed "poof" if enough heat is present at a high enough FO2, and so will Viton and EPR O-rings - despite their "O2 compatable" claims. For that matter, Christolube will decompose if it gets hot enough according to its MSDS, and what it decomposes into is really unhealthy to breathe. Adiabatic heating on a localized basis can be quite extreme if you slam 3,000 psi gas into a closed HP orifice or sharp corner.

An awful lot of avoiding incidents come down to not doing that. No heat, no fire.

[DeWayne]

I have yet to have any problems with viton lasting a year or better between service. The key is as Karl mentioned above, dedicate your system and keep it well maintained and clean. I would venture to guess that most of the problems reported have more to do with high pressure O2 and resultant cross contamination. I have yet to see a need to bring deco O2 above 2400 psi and my DR 1200 is still supplying it with no problems.

[curtschu]

Question, What is the biological advantage to using 100% o2 Vs. a lower Ppercentage? I am assuming this is a deco gas. I remember discusing these aspects at lenth several years ago and the concensus then was that anything more than 50% O2 was enough for final deco. I have been out of the loop for some time and I'm just entering back into the Tech diving realm. Has something changed?

[Genesis]

Question, What is the biological advantage to using 100% o2 Vs. a lower Ppercentage? I am assuming this is a deco gas. I remember discusing these aspects at lenth several years ago and the concensus then was that anything more than 50% O2 was enough for final deco. I have been out of the loop for some time and I'm just entering back into the Tech diving realm. Has something changed?

Offgassing rate is controlled by the difference in partial pressure of inert gasses in the blood .vs. that in the inspired gas.

Oxygen has zero inspired PP(inert). It therefore offgasses at the same rate irrespective of depth. So while you can only breathe it down to 20' safely, if you continue to breathe it to the surface and for a few minutes after, you continue the high-rate offgassing.

If you use 50%, then your offgassing rate decreases as you rise in the water column.

In a situation where you have a stable decompression platform (e.g. caves, etc) and you can easily "post-breathe" the O2 on the surface you gain some advantage.

In the ocean for 'light deco' I tend to take a 50% bottle, but that's mostly because I can get on the decompression gas deeper and if something goes wrong environmentally (e.g. a shark molesting me, a blow-up thunderstorm, etc) I can get out of the water with some benefit and less risk, where if I was using only O2 I'd be hosed. On a cave dive its a bit different, in that envronmental considerations are less likely to arise and the benefit from post-breathing the O2 is significant, especially when you have to climb a set of stairs post-dive with your tanks on your back.

[normblitch]

Question, What is the biological advantage to using 100% o2 Vs. a lower Ppercentage? I am assuming this is a deco gas. I remember discusing these aspects at lenth several years ago and the concensus then was that anything more than 50% O2 was enough for final deco. I have been out of the loop for some time and I'm just entering back into the Tech diving realm. Has something changed?

Curt,

Like you, I am a "returning" Caver...

My decision to use 100% in a stage 40 was based on two (both possibly flawed) final considerations:

1, the desire to have a source of 100% for surface use if need be for DCS treatment or other first aid needs,

and 2, knowing that 100% has a MOD of 20 feet, I would NEVER be tempted to carry it to a greater depth, where an error in reg selection would prove fatal...

(I know that SW tech divers often carry a leaner deco mix allowing for deeper switches, but I do NOT see me in those scenarios any time in the forseeable future...this is for FW use ONLY)

Norm

[normblitch]

There is no guarantee when it comes to O2 incidents. Be aware that despite the claims of "O2 compatability" nearly all seats used in regs today will indeed "poof" if enough heat is present at a high enough FO2, and so will Viton and EPR O-rings - despite their "O2 compatable" claims. For that matter, Christolube will decompose if it gets hot enough according to its MSDS, and what it decomposes into is really unhealthy to breathe. Adiabatic heating on a localized basis can be quite extreme if you slam 3,000 psi gas into a closed HP orifice or sharp corner.

An awful lot of avoiding incidents come down to not doing that. No heat, no fire.


Genesis,

As always, your comments are well spoken, and worthy of cut & snip to the notebook...Many Thanks!

Norm

[normblitch]

I have yet to have any problems with viton lasting a year or better between service. The key is as Karl mentioned above, dedicate your system and keep it well maintained and clean. I would venture to guess that most of the problems reported have more to do with high pressure O2 and resultant cross contamination. I have yet to see a need to bring deco O2 above 2400 psi and my DR 1200 is still supplying it with no problems.

DeWayne,

You (along with others) make consistant refs to constant cleanliness...

My ally 40 (alas) doesn't have a DIN valve...and I am NOT enthused by the idea of a plain valve cover...suggestions?

Also, are y'all advocating keeping the O2 reg set in a sealed box like a Pelican?

Norm

[Genesis]

My decision to use 100% in a stage 40 was based on two (both possibly flawed) final considerations:

1, the desire to have a source of 100% for surface use if need be for DCS treatment or other first aid needs,

and 2, knowing that 100% has a MOD of 20 feet, I would NEVER be tempted to carry it to a greater depth, where an error in reg selection would prove fatal...

(I know that SW tech divers often carry a leaner deco mix allowing for deeper switches, but I do NOT see me in those scenarios any time in the forseeable future...this is for FW use ONLY)

Norm

Yep. All good arguments in a cave.

In the ocean I don't drop bottles, as a general rule. Of course in a cave you usually have to come back the way you came. This is definitely not true on a wreck dive, and a large number of fatalities have had as factors the loss of a decompression gas as the consequence of dropping it and then being unable to get back to where it was.

I've also got a protocol for gas switches that I follow no matter how many I'm carrying - done right, there's very low risk. As you mention, that's a mistake you will only get to make once, so making sure you've got a protocol that prevents those sorts of mistakes and using it every time you gas switch is a really good idea.....

[Genesis]

My ally 40 (alas) doesn't have a DIN valve...and I am NOT enthused by the idea of a plain valve cover...suggestions?


Just blow it out by cracking the valve before you put the reg on. Do it SLOWLY.


Also, are y'all advocating keeping the O2 reg set in a sealed box like a Pelican?

Norm

I don't go that far. I do, however, have a well-sealing cap for my first stage.

[Caver95]

1, the desire to have a source of 100% for surface use if need be for DCS treatment or other first aid needs,



(Norm
Would a hangover fall under other first aid needs?

[curtschu]

Ok I understand the theory of the pure o2 vs. a mix but with all the inherent problem with contamination is it really worth the trouble?

It might be easier and safer with respect to reason number 2 to invest in a DAN o2 kit and have it on hand for a DCS incident.

Like I said I just wonder has medical research been done to check the theory vs real life as far as off gassing is concerned.

[Genesis]

Ok I understand the theory of the pure o2 vs. a mix but with all the inherent problem with contamination is it really worth the trouble?

It might be easier and safer with respect to reason number 2 to invest in a DAN o2 kit and have it on hand for a DCS incident.

Like I said I just wonder has medical research been done to check the theory vs real life as far as off gassing is concerned.

Yes, because any mix of 50% and over is nearly as dangerous as 100%.

NASA has done testing on this, and for all intents and purposes once you cross the 50% line you better treat it as 100%.

The problem, of course, is that for mixes you HAVE TO risk contamination, since you have to get the air top in there somehow!

So basically if you're going to take a deco gas, take the one that's right for the conditions you expect to encounter, and the one which gives you the right balance of beneifts .vs. risks.

For the ocean and a single gas that's usually 50% for me, and for caves, its usually 100%. On the boat I have a DAN O2 kit (for emergency use) as well....

[DeWayne]

As Karl mentioned Norm, there is nothing special to maintaining a clean environment for your O2 setup. I do keep my my caps and plugs separated so there is less chance of contamination, but do not seal things in a pelican case or any other special container for that matter. Anything that will keep contamination out of the valve will work. Just always be mindful of what you are doing and that will go a long ways. The key to safe O2 handling is think and go slow.

[normblitch]

1, the desire to have a source of 100% for surface use if need be for DCS treatment or other first aid needs,



(Norm
Would a hangover fall under other first aid needs?

D***

I had HOPED that I wasn't THAT transparant...it seems the rep of my Old Habits preceed me...

<g>

Norm

[normblitch]

[/quote]

I've also got a protocol for gas switches that I follow no matter how many I'm carrying - done right, there's very low risk. As you mention, that's a mistake you will only get to make once, so making sure you've got a protocol that prevents those sorts of mistakes and using it every time you gas switch is a really good idea.....[/quote]

...I'd like to hear the protocol if you could share...

Norm

[normblitch]

My ally 40 (alas) doesn't have a DIN valve...and I am NOT enthused by the idea of a plain valve cover...suggestions?


Just blow it out by cracking the valve before you put the reg on. Do it SLOWLY.


Also, are y'all advocating keeping the O2 reg set in a sealed box like a Pelican?

Norm

I don't go that far. I do, however, have a well-sealing cap for my first stage.

Are you describing the usual cone-head 1st-stage cover found in LDS's?

Norm

[Genesis]

No; my regs are DIN.

If you have yoke, the key is a well-sealing cap. Scubapro's works well. A lot of others are hard plastic and don't seal worth you-know-what.

[normblitch]

Ok I understand the theory of the pure o2 vs. a mix but with all the inherent problem with contamination is it really worth the trouble?

It might be easier and safer with respect to reason number 2 to invest in a DAN o2 kit and have it on hand for a DCS incident.

Like I said I just wonder has medical research been done to check the theory vs real life as far as off gassing is concerned.

Curt,

Were but I a Lotto winner, I would have BOTH an O2 stage AND a DAN O2 kit in my Land Rover or Excursion...being as how I STILL haven't won (Hence the '99 Windstar BGDV), the cost factor forces my decision...the O2 stage has TWO uses; the DAN kit performs poorly at 20 FFW ... <g>

Norm

[BillGraham]

I'm curious to know if I'm doing something wrong here. I have a pile of Poseidon Odins, they are all O-2 cleaned, my theory is that any of them can be used interchangably. Does breathing Nitrox through one somehow contaminate it? My tanks are all O-2 clean.

As for protocol, I try and label the tanks really clearly, I like those wraps because you can switch them around on different tanks. I also make it so that I've got to do a couple of things before I can breath off the tank. There's a loop of innertube over the mouthpiece, which forces me to look at it and move it, and then I need to turn the valve on (I leave them charged, but off).

I almost always drop my deco gas on wreck dives, because I don't like pushing all that stuff through the water. I plan my dives so that I can do the whole thing on back gas if I have to. I usually run a reel (Northeast U.S., challenging vis) and the end of the line is tied to the bottles. The only time I don't put them down is when there's so much monofilament and fishing gear on the wreck that I'm afraid to touch it :?

[TRIBOLUBE71]

There are alternatives to christolube.


Depends.

If you use EPR (EPDM) O-rings, and you should, there should be no issues with regular service intervals. There can be issues with things like diaphrams though, as I've yet to see anyone be real clear about exactly what kind of material they're made of and how their lifetime is impacted by pure O2.

One thing that IS important is to dedicate the reg to pure O2. If you NEVER boost into your 100% tank, filling ONLY by transfilling from an O2 supply cylinder, there is never any contamination source that goes into the tank, valve - or your reg. This radically reduces the risk of an "event".

If you DO boost, then you have raised the bar considerably, because now there's a booster there that can cause contamination or "shed" particles that can become trouble. If you don't own the booster, then you've just added an unknown as you have no way to know when it was last torn down and overhauled or what kind of internal condition it is in. If you exchange the reg onto other tanks, ditto - as soon as you jack it on a tank that contains anything other than pure, gas-supplier-provided O2, you are introducing contamination. Even with a hyperfilter on the gas supply (which should be used IMHO on ALL breathing gas systems - and I'm well aware it often is not!) very small amounts of contamination do get through, and their impact is cumulative.

My personal protocol is that my O2 reg ONLY goes on my O2 bottle, and when not on that bottle is capped with a sealing delrin DIN cover. The O2 bottles themselves are dedicated to this service and never see anything other than a transfill off an O2 supply cylinder. I trust my gas supplier not to sell me a contaminated O2 tank, because odds are that if they did it would blow up in their facility - before I got my hands on it. This is easy for me to do, because I mix my own gas - this level of control is a LOT tougher if you BUY gas from a shop, because you have no control over the transfill whip used or how its handled (did the guy who used it last get finger oils on the DIN filler O-ring?) and, if they boost anywhere along the line (even from their supply to a storage tank) then the cleanliness issue is off the table.

If you can't maintain this level of control then I'd be tearing that reg, tank and valve down every six months and giving the valve and reg a good O2 cleaning in the Ultrasonic, plus giving the tank a good wash-out with Blue Gold.

I also like first stage regs for this purpose with nice, short, straight gas-paths internally with no convoluted places for gas to impinge on and cause adiabatic heating. IMHO simpler is better, and there's no point in a balanced design, since you can't breathe the O2 below 20' anyway. All the balanced design does is add twists and turns, along with nooks and crannies, to the gas path.

And, of course, always crack valves and fill O2 tanks S.L.O.W.L.Y.

There is no guarantee when it comes to O2 incidents. Be aware that despite the claims of "O2 compatability" nearly all seats used in regs today will indeed "poof" if enough heat is present at a high enough FO2, and so will Viton and EPR O-rings - despite their "O2 compatable" claims. For that matter, Christolube will decompose if it gets hot enough according to its MSDS, and what it decomposes into is really unhealthy to breathe. Adiabatic heating on a localized basis can be quite extreme if you slam 3,000 psi gas into a closed HP orifice or sharp corner.

An awful lot of avoiding incidents come down to not doing that. No heat, no fire.

[Tegg]

Nice spam post David... :roll:

[pittsburgh cave diver]

I use a inexpensive sherwood brut for my 100% o2 deco reg, simple to overhaul, piston, and as others said bulletproof, and very reliable
it is unbalanced, but i used it from 20Ft on up, i use it on an AL40 all Din, with Viton and crystal lube and have used it for 8 years of cave diving so far and never had any issues. I do fill my bottle myself (trans fill) and never go over 2000psi. Even when i tear it down every 2 years it show no signs of problems using it in a pure o2 enviornment. (the reg or bottle) I just cap the reg, and bottle when not in use. I only use 100 o2 in deco in caves and often drop the bottle at 25feet, just because if i leave it at 20, my computer goes hay wire if it get to 21feet while picking it up, so i do the pick up 5 feet deeper then required then get to 20feet and nestle into a spot and switch to my o2 and hang out till i clear, then do another 5min, slowly assend and do 3 min surface deco on 02 before i attempt to exit.