First stage piston lube

[Akimbo]

Does anyone spray lubricant in their piston first stage regulators for preventive maintenance? The complete procedure is to flush the spring cavity with fresh water, let dry, and spray an Oxygen compatible lubricant in the ambient pressure sensing ports of the spring housing. The idea is to maintain lubrication and inhibit corrosion on the two piston seals exposed to sea water.

Naturally, this only applies to first stages that do not have an anti-freeze kit. It makes sense for balanced flow through and unbalanced pistons. It would have minimal value to diaphragm regulators.

It has been a common practice for a long time in my sphere of visibility and I am curious that I never see it suggested in recreational diving.

 

[Mr Carcharodon]

I do not, and in fact the only lubricants I use are greases and not very sprayable. Not having done this before I would concerned about a lubricant being fluid enough to spray getting past the piston o-rings and into the breathing gas.

What kind of spray lube do you use?

 

[Akimbo]

I do not, and in fact the only lubricants I use are greases and not very sprayable. Not having done this before I would concerned about a lubricant being fluid enough to spray getting past the piston o-rings and into the breathing gas…

I believe it was Navy clean room techs that started us on the procedure in the early 70s. The practice was common on most commercial job sites before I arrived. The viscosity of the spray Silicon is about the same as a light oil once the vapor has coalesced. It is unlikely that any of the lubricant would migrate to a higher pressure stream. But even if some did, it would be no different than the exposure we have now.

It functions more to reduce the rate that grease applied to the O-ring washes away than as a primary lube on the O-ring. It is definitely a better procedure for a new or newly rebuilt mechanism than one that already has a dry O-ring and debris build-up.

What kind of spray lube do you use?

I am still working on cans of IKV Tribology's Fluor 70 Spray from the UK.

Manufacturers and UK suppliers of performance lubricants, synthetic oils and greases, high & low temperature oil, grease & dry film coatings

Before that we had some Mil-Spec stuff, from DuPont on think. I have not tried Tribolube's spray yet. You can also use an Oxygen compatible light oil, but you just have be to more position sensitive.

I have a first stage that I have not opened in about twenty years just to see how long the IP will remain stable. To be fair, it was in storage during a 6 year period while I was building a house. I mostly use it for recreational diving and carry a spare first stage for when it does fail, but it is an interesting experiment.

What lube are you using?

 

[halocline]

I've never bothered to do anything like that, just rinse well and let dry. It's an interesting idea. I'm going to pack my MK10s with grease; that should definitely keep the water out.

 

[knowone]

 

[knowone]

 

[Akimbo]

... I'm going to pack my MK10s with grease; that should definitely keep the water out.

The only disadvantage I see with packing grease in the ambient pressure ports, like anti-freeze kits, is it makes it hard to spot small bubbles from a slow leak-by on the piston seals. If you don’t check now, I suggest pressurizing your regulator periodically for leak tests; which is also a good time to soak them.

I have noticed that most new recreational divers don't inspect their first stage inlet filters. A clogged inlet filter is the only failure of a modern diving regulator I have seen that caused a catastrophic flow restriction. All other failures I have seen or heard of caused free-flows — inconvenient but rarely hazardous. It is ironic since so many new divers view regulator reliability as critical as space shuttle components, yet they don't even look at the one thing that could cause a dramatic loss of gas.

Thinking a little more, the grease could become contaminated with fine particles or even dried salt which would cause O-rings to wear faster. This is a theory off the top of my head but you might consider it.