Is titanium with Nitrox bad or not to wory?

[daversj]

Poping my cherry with this post. I have been reading the board a while. Any way... I have a Mares v32 1st stage with the Proton Metal 2nd. Aparently the 1st stage has some titanium parts in it to reduce wear or anti corrosion or whatever. The setup breathes like butter and only paying $299 for it I'm real happy. Now I'm hearing that titanium in combination with oxygen isn't a good thing. Should this be a concern because I'm not giving up the nitrox. Are we splitting hairs with the titanium thing? Also, I am upgrading to HP steel 100's or 120's. I was planning on mostly filling to 3000psi with an occasional 3500psi fill using nitrox. Does the high pressure cause such significant wear to the 1st stage that I should refrain from a full fill? A more frequent service interval necessary? 3500psi Nitrox ok with the titanuim parts? What are the practical issues here? Any insight would be appreciated. Thanks, Dave

 

[fdog]

A hearty welcome to the board, Dave!

This topic has been thrashed adnauseum here. May I humbly suggest using the "search" button, which you did not have access to before you were a member. You will find a whopping number of threads.

To get you started try this thread or this one .

All the best, James

 

[daversj]

Thanks for the welcome and the links. I searched the posts but I'm still not shure on the titanium thing. The V32 isn't a solid titanium body 1st stage but the internals have a titainium popet, if i'm not mistaken. Is it safe to use say 36% nitrox with that reg? How about at 3500psi with that same mix? This month I've done 10 dives with 36% from a 3000psi fill and no fires. If it's a problem can I replace the Ti part with a stainless piece? I don't want to start any fires, it might scare the lobster.

 

[Doc Intrepid]

Dave,

Without knowing the internal specifics of your reg (and tank valve(s), so long as its been O2 cleaned and has oxygen compatible lubricants, orings, etc., it should be fine for EAN up to 40%.

Reason you should pay attention to the valve depends on whether your supplier(s) offer partial pressure blending or continuous blending. If 100% O2 is flowing through the valve, (as part of the blending process) the valve should be O2 cleaned.

Unless you're into decompression diving, its unlikely you'll be running EAN beyond 40% through the regulator anyway.

 

[scubatoys]

If you're just using recreational nitrox - up to 40%, you don't have to do squat... No special lubricants, no special o-rings, and the titanium is fine. I'm diving an all titanium Mares TI Planet - straight out of the box - and it uses the same internal spherical core seat as your reg - and the entire 1st stage, is titanium. Truck Lagoon, Palau, Cayman, Turks & Caicos - all on nitrox day after day... no problem.

(As pointed out above... your tank treatment will depend on how it's being filled... but the reg... no problem.)

I was a guest at the Dan conference in Dallas - showing Medical examiners what kills divers and how to do autopsys on them... I wasn't cutting up any divers - just there to show the guys the gear, how to tear it down and remove it from the body...

But anyway, they had a pile of every stat on injury or death of divers since the begining of records on it....

Not 1 case ever... Never - Not 1 - of any problem with Nitrox mixes below 40% with any materials - titanium, rubber, silicone...

So I'd tell you - don't do a darn thing with your reg other than dive it...

 

[will_tekkie]

I was planning on mostly filling to 3000psi with an occasional 3500psi fill using nitrox. Does the high pressure cause such significant wear to the 1st stage that I should refrain from a full fill? A more frequent service interval necessary? 3500psi Nitrox ok with the titanuim parts? What are the practical issues here? Any insight would be appreciated. Thanks, Dave

Dave..the problem to fill tanks using nitrox ( or other mix) to 3500 psig is the fact that gas become VERY no linear and for example a partial pressure mixing, the most common method used, where ideal gas law are ussually assumed for simplicity with no compressibility factors added, also became harder to perform with the same % accuracy reached under lower pressures...i´m not really like filling tanks to such pressures thinking in the increased stress under the reg parts..a HP seat failure in such conditions could be higher to happen...If your diving is done in cold water a HP tank is something that you HAVE to avoid...(temperature drop and induced freezing is a real concern)...

About Ti and Nitrox..as said above..under 40% O2 everything used in modern reg are ok...the problem for some metals and alloys like Titanium, Stainless Steel and others is its VERY high combustion temperature and the danger that it would be...these metals are Strictly forbidden by codes for nitrox and other O2 filling systems...

I´ve read a post from someone ( i think was Greg Barlow..i not sure now) about Ti alloys in reg...this is the aswer to a problem that does not exist...marine brass is a great and relatively cheap alloy..Ti is not needed at all...for faster responses brands are using mostly plastic poppets in seconds stages...easy to build, cheap to buy..cheap to replace...

 

[daversj]

Thanks for the replies guys. I guess I'm good to go. This site is a wealth of info that makes me want to learn more. The water is a little cold here in NY so at least I can talk about diving. I'm in withdrawal from a week of diving in FL. and cant let it go.

 

[Scubaroo]

Well in Oz the standard tanks are 232 bar and 300 bar - that's 3410 psi and 4410 psi - I enquired about regulator HP seat wear after being used to diving LP 2640 psi tanks, and no-one here seems to experience any unusual problems at the higher pressures.

 

[Greg Barlow]

One of the main reasons why Mares uses a titanium poppet is due to the low mass of the part. This allows it to respond quicker than if the part were made from a stainless alloy.

It will not be a problem unless you go to technical blends such as EAN80 or pure oxygen. I would probably even use it with EAN50, which I use for many of my dives.

Adiabatic heating from the rapid compression of gases is what the danger is based upon. I strongly suggest holding down the purge button on the second stage while opening the valve slowly, this goes a long way toward preventing any problems.

Titanium will serve as a fuel for a fire. It will ignite at a much lower temp than most stainless alloys. Brass has a very high ignition point, and is therefore the safest alloy typically used.

That said, I personally use Mares regs utilizing the titanium poppets for my back gas. I use the stainless poppets for my deco bottles.

By the way, anytime that you use higher pressures, the wear and tear on HP poppets/seats is going to be worse. That is simply the nature of the beast. Anything over 3,500psi, 232bar is pretty tough on HP seat materials. They will inevitably wear out quicker.

I wouldn't worry about the titanium alloy or pressure for general sport diving. Your annual rebuilds should likely be more than enough.

Greg