safe for O2 use products...

[rhwestfall]

can anyone please shed some light on this one (documentation)? Is this O2 safe or not? Can't glean anything off the MSDS sheets....

I hear references to DOW 111 as O2 safe....

DOW Corning Molykote 111 -

There seems there might be two different products using similar terminology, and that is likely very dangerous...

 

[dberry]

I'll look them up, but if Dow Corning makes it, it's very likely to be silicone grease based. Almost certainly with some molybdenum sulfide powder added (moly sulfide looks and feels a lot like graphite powder - a "dry lubricant").

In any case, silicone grease is definitely not O2 safe, and my gut reaction (as a chemist) is that moly sulfide plus high pressure O2 would be highly unstable.

[edit]
Dow Corning describes MolyKote as a line of industrial lubricants. There are several products listed under the general term "MolyKote M". MolyKote 111 is indeed silicone based, although it does not contain moly sulfide. And the MSDS for MolyKote 111 contains this little gem:

"Can react with strong oxidizing agents."

I think that confirms the expectation that silicone oils and greases are not suitable for HP O2 work.

 

[tbone1004]

Dow 111 is a silicone lube, not O2 clean. Not sure what the similar terminology causes concern but dow 111 is the standard cheap lube we use for non o2 clean applications

 

[rhwestfall]

Dow 111 is a silicone lube, not O2 clean. Not sure what the similar terminology causes concern but dow 111 is the standard cheap lube we use for non o2 clean applications

I thought so too, but recent past, somewhere, DOW 111 was mentioned for O2 safe, and my head is spinning....

 

[axxel57]

It's a bit confusing, because Dow and Christolube use a 111 for their products.

Molycote DOW111 is a silicone used for tank valves to be screwed into aluminum tanks to avoid galvanic oxidation.

It produces a barrier between the brass tank valve and the aluminum threats of the tank, it's definitly not for O2 applications.

Christolube 111 is used to lube brass with brass or plastic or stainless steel connections. It's the standard lube for O2 applications in scuba regulators.

Since it cannot produce a working barrier between brass and aluminum, it's probably not a good idea to use it on tank valves.

On the other hand I would not use DOW111 in regulators without O2 concerns even when I think it could be used for lubrication between brass and brass and even if it is much cheaper

It's just very sticky, if used too much quite a mess in a reg, and quite sure would dry faster than Christolube111 in regulators if used as little as Christolube normally is used.

 

[tbone1004]

@axxel57 you aren't supposed to lube tank valves.... I get the Dow vs. Christolube thing, but different brands so nothing they could do.
Dow 111 typically lasts quite a bit longer than Christolube which tends to dry out. The Dow doesn't really dry out. It's a bit annoying since it's sticky, but it is one of the standard lubes used for non-o2 clean applications

 

[axxel57]

tbone, what a nonsense is that, not lubricating tank valves on aluminum tanks?

Not doing so will lead to galvanic corrosion on the threads of the tanks, which first might mean seizure of the valves in the tanks.

You will probably have quite some problems to take off the valves from aluminum tanks, and more important, it means material loss on the tank threads in the long run.

It is correct not to lube the neck o-ring to avoid the danger of extrusion, maybe you mixed that up, but all aluminum tank manufacturer recommend to put a lttle bit of DOW Corning 111 on the lower part of the valve threads, which then is distributed on all threads when screwed into the tank.

DOW111 has never been recommended by the manufacturers for regulator applications as far as I know, but if you like it, it lubes.

 

[tbone1004]

@axxel57 correct on the bottom 2-3 threads but not the o-ring. I don't know if it's galvanic corrosion since it is chromed brass, but it definitely prevents galling.

regarding the 111, I'll dig through, but I know it's spec'd in a couple manuals I have for lubricating o-rings. Granted, these are older manuals so the new ones may all spec o2 lube

 

[halocline]

The galvanic action between aluminum tank and brass valve is a real concern, but I don't use molycote for it, I just use a bit of ptfe grease like christolube. I'm sure it doesn't coat the threads as well or provide as reliable a barrier but those valves are not installed tightly, they are chrome plated, and they come out every year for VIS. So at least with my tanks the chance of valves getting stuck in place due to galvanic action is very low.

 

[Rred]

FWIW, federal law in the US requires all manufacturers of chemicals that may be shipped across interstate lines to have the MSDS information available 24x7, one way or another. In practice this means you look for an 800# on the product label, call the corporation, and an "MSDS compliance person" usually will be found and put on the phone. There are also multiple web sites that almost always carry MSDS listings for products.

I've found a few boneheads that won't release an MSDS until you complete an email form requesting it, but tey're the exception to the (fairly clear legal) rule.

The "O2 safe lubes" normally used in the dive industry are generally used for a reason. If price is no object, I'm personally a DuPont Krytox fan. There's a whole family of Krytox products these days, some distributors will sell samples very reasonably. And both DuPont and Dow are very good at answering phone calls and suggesting "most appropriate" products to folks, just over the phone.

Krytox is like antiseize: In that it seems damned expensive, until you realize how sparingly you can use it, and that one dab lasts forever.