Junk in my MK10+

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The photo of three different filter photos is pretty interesting. That explains something.

I mentioned that I was comparing a new MK10 filter to this MK10+ filter. You guys might remember, I showed you a picture of this MK10 a little time ago. I was remarking how I couldn't get over the pristine condition (unused I had guessed). So that all makes sense - the MK10 filter is 'new old stock' - dates back to when they made them finer.

Mattboy - I did the finger nail thing on the piston tip - couldn't feel any nicks. I've got loops from 4x to 25x - the tip seems OK to my untrained eye. Maybe there were some particles there at one time and I knocked them off as I was doing the disassembly.
 
Back to the powder, I'm trying to think of what I do that might cause this.

Hmm, when I get on the boat after a dive, I've got a small plastic bottle with a small tip on it. The bottle is filled with clean tap water. I not only squirt off the exterior of the first stage, I squirt water through the holes leading to the ambient chamber. Hmm, if the reg is not pressured, might mineral rich tap water get drawn past the o-rings into the high and low pressure chambers?
 
The HP piston stem o-ring seals air pressure up to about 3500 psi and the LP piston head o-ring seals air pressure to at least 160 psi with no leaks and the o-rings seal equally well in either direction, so the odds are very slim that water squirted into the ambient pressure holes would get past either piston unless you used a 4000 psi pressure washer.
 
Perhaps the substance is some other type of thread lubricant that is in a powder form. Locksmiths use a sort of graphite type lubricant in lock tumblers. Perhaps a call to the shop that performed the last service is in order.
 
Perhaps a call to the shop that performed the last service is in order.

Yeah, I thought about that. The repair tech that did the work is very good. But he's kinda gumpy and doesn't seem to like to talk on the phone (let alone, use the internet). He'll want to see it - understandably. He's 30 miles up the coast (shop is near one of my dive buddies home - which is the reason I occasionally end up there). But right now, I don't feel like driving 30 miles just for this. Further, I got a year's worth of dives out of this rebuild so I don't feel like the repair guy owes me anything.

I've got another very good repair guy at DiveNsurf (the Body Glove folks). He's just a few miles away. I have to pick up something there next week and will probably take this MK10+ in to show him. I think when a knowledgeable person is able to physically examine this thing, it will probably be easier to figure it out.
 
Well, if you said that your IP is "off the charts" and it was rebuilt about a year ago, and you are careful enough with your reg to squirt fresh water in the ambient chamber, I would take that as an indication that something's wrong. Grumpy or not, if he rebuilt a reg that has IP problems a year later with good maintenance, he ought to realize that.

The fingernail inspection of the piston edge is okay, but I think especially on those rounded edges, the loupe is better. An advantage of the rounded pistons is that they increase flow, and if they match perfectly with the seat there's very little wear and tear on the seat. A disadvantage is that even tiny scratches or imperfections will really cause creep. The sharper knife edge pistons cut into the seat by design and form their own mating surface.
 
Larry,

You are right about the separation of oil, this is natural in all greases. Hint: squeezing the tube back and forth prior to use will mix back to a homogeneous grease if there has been any separation. To function properly the oil must be able to be used in the system where it has been placed. Greases are made of a thickening system that holds the oil in place until it needs to be used for lubrication. The oil in fact is what you want in the static and especially dynamic applications. There are several choices for this thickening system. The most effective will be a particle that is submicronic and has a large surface area for the oil to attach. This is the Thickening system that is in Tribolube 71.The grease that is in the picture has lost almost all the oil and the PTFE polytetrafluoroethylene (Teflon) thickener is all that is left. This has also been noted in other parts of the regulators that are static and dynamic. The scale, residue, gel, or cookie dough you see when you open your regs to service them is the thickening system left behind as the oil is lost from the grease. Sometimes people put way too much grease on the parts. You just need a small amount to cover the threads, O-ring, or parts that you want to protect with oxygen compatible grease.

The blue green corrosion that is visible in the pictures is avoidable. While the interval maintenance is being done spray on a small amount of Tribolube EPO2 corrosion inhibitor. This product acts to passivate the surface and block contaminants (salt, salt acid, oxygen, and other hydrocarbons) from affecting the metal and interact causing the corrosion.

Cleaning off the residue is possibly difficult and time consuming. Standard cleaning consists of a brush of some kind and an ultrasonic cleaner. We have a solvent that is oxygen compatible and is specifically made to remove the oxygen compatible grease or the residue left behind in the regulator. This product is called Tribolube KO2, and works on any PFPE oxygen compatible grease not just Tribolube.

We have not seen this dried out white residue to date, and many tests have been done with multiple regulators and rebreather manufacturers. Hope this information is helpful. For any further questions email or PM me.

Regards,

David



The idea behind the filter is not to clean the gas, but rather just ensure any impurities that pass are small enough not to damage the reg.

Scubapro has had three different conical filter styles for it's regs over the last 20 years or so. They are displayed left to right from earliest to latest.

1. Sintered metal - small grained and thin walled. This has been the standard until about 4-5 years ago.
2. What appears to be compressed wire - much thicker walled, softer and more prone to being crushed or bent. This design only lasted a couple years.
3. Sintered metal but larger grained and thick walled. It came out a year or 2 ago. It is courser than the earlier filter, but the gas passes through about twice as much of it so I don't think much more of anything gets through it.

-----

I considered the possibility of dried lubricant, but I have never seen Christolube do that - especially after only a year. Christolube thickens a bit over time with long term exposure to air, but it does not dry out and get dusty.

I have tried Tribolube and have noted one tube (out of several) where it was prone to separate into a thicker white paste and a clear liquid, but even then I do not think it would dry out completely in only a year.
 
I thought I'd come back here and close the loop.

I think I can say with some confidence that I've confirmed that this stuff is AL oxide - as many of you had suspected. It's not a residual component of lubricant.

This turned into a very lengthy dialog (off of scubaboard) between myself, several divers, the Dive Operator and the tank filler. The Dive Operator and the tank filler have taken this matter seriously. Within 24 hours of contacting the Dive Operator, numerous tanks - which we think may have caused the problem - were identified, pulled from service and set aside for inspection. The Dive Operator and filler had a meeting to discuss the situation (I think there was an agreement to do visuals on all tanks - not positive about that). The filler agreed to tighten up their protocol (inspection, identification, tank usage).

I made a point of asking them to not only check tank condition but to also double check that there was a dip tube in all the valves.

On a number of occasions I've come across DA Aquamaster's suggestions about doing a simple pre-dive tank check when using rental tanks: Pick the tank up, hold it by the ends and tilt it back-and-forth listening for water and a loose dip tube sliding around. I'll definitely be doing this on my next trip south-of-the-border.

I'd like to recommend that DA's 'tip' about pre-dive tank checks be turned into a 'sticky'.

Now, if we could just figure out if some nitwit has removed a valve from a tank, dumped out the broken dip tube, and reassembled the valve/tank sans dip tube!
 
Beachnik,

Aluminum oxide should be quite "gritty" (you've already tasted it, why not give it a chew?). This looks more like plastic - teflon or something like that. Would you agree?

How on earth could so much "aluminum oxide" work its way into the threads like that, leaving none on the filter? If it came from the tank, then this stuff should be all over the place. This isn't the case right?

My money is on someone using thread sealant on the cap. If it were mine, I would be having serious words with the reg tech.... and I would be the grumpy one!

Jason.
 
https://www.shearwater.com/products/peregrine/

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