Mk11 Split-off from Regulator Geeks, Part II

[Open Ocean Diver]

Any need for special cleaning with titanium regs when using 32 or 36%

I’ve been told by experts on this site that O2 cleaning is not necessary for Nitrox mixes contain 32% and 36% oxygen.

Can anyone confirm this please?

 

[rsingler]

Correct. The assumption is that the regs were delivered Nitrox-ready when purchased and have not been silicone-lubed since, nor had gross hydrocarbon contamination.
What "cleaning for Nitrox" means, and the safety of garden-variety nitrile o-rings in Nitrox, is debated.

 

[Bigbella]

I’ve been told by experts on this site that O2 cleaning is not necessary for Nitrox mixes contain 32% and 36% oxygen.

Can anyone confirm this please?

We first began futzing with nitrox in the mid-1980s, with cobbled together tables -- about 32 to 36% mixes -- and did absolutely nothing, whatsoever, to our regulators, in terms of swapping out nitrile for viton o-rings.

Specialized rebuild kits didn't yet exist; and both types of o-rings would eventually degrade under the higher FO2s anyway — that, and we never used anything more exotic than silicone grease for lubrication.

None of our gear was ever "dedicated EAN" -- and everything was used interchangeably with straight compressed air. We couldn't afford multiple regulators, for each "flavor" of gas, or for exclusive nitrox use, for that matter; nor was it readily available outside the US, at the time.

Perhaps we were just lucky; but there wasn't much in the way of any real concern from those then supplying the mixed gas. "Aviation practice, it's interesting to note," wrote Harlow, in his 1999 regulator book, "is to use nitrile for O2 applications."

The first time I ever saw a tub of Cristo-Lube was in the early 2000s; and even then, it was just being used by Aquatica to lubricate o-rings in their underwater camera housings, since it was considered less "sticky" than silicone grease and was thought to attract less grit to critical seals . . .

 

[Open Ocean Diver]

Correct. The assumption is that the regs were delivered Nitrox-ready when purchased and have not been silicone-lubed since, nor had gross hydrocarbon contamination.
What "cleaning for Nitrox" means, and the safety of garden-variety nitrile o-rings in Nitrox, is debated.

Thanks Rob, I think you were the expert I was referring to. Lol