Junk in my MK10+

[beachnik]

About a year ago I had an MK10+ rebuilt. Then I did about 60 dives on it. I just disassembled it - this is the first time I've looked inside one of these. I saw something interesting. See the tight photo of the seat retainer with HP seat still installed (click the thumbnail image to enlarge). Take a look at the powder like debris most visible along the edge of the top thread (you guys already know, this powder is scattered throughout the first stage). It's a very fine powder that you can easily wipe off, gray color.

Ques:

• Is that particulate matter from the filter?
• It looks excessive for 60 dives - yes?

Probably explains why my IP was off the charts.

One more question...

What you see in the tight photo is everything that came out of that end of the regulator. Notice it doesn't match the 1997 Technical Service Schematic for the MK10+. The schematic shows an extra o-ring that seems to butt up to the HP seat. I'll bet they did an inline design change that consolidated the o-ring and HP seat into one item - yes?

 

[hudson]

The white powder looks like oxidation from an AL tank.

 

[DA Aquamaster]

The schematic is correct, and the the o-ring is present on your reg. It goes in the groove around the seat. If you remove your seat from the seat carrier you will see it.

the white powder could be oxidation from an AL tank, but if that is the case, the filter in the yoke or DIN retainer should be nearly plugged with it as well.

If the filter looks clean, it is coming from somewhere else.

 

[tfsails]

That white powder doesn't look to me like it's anything that comes from within the first stage, and doesn't look like corrosion to me. At least not corrosion from within the reg as if salt water got into it. That corrosion would be greenish-blue. If you use the same tanks regularly, you might want to get them VIP'd to check for any oxidation in them. If you use rental tanks, who knows where the powder came from. DA Aquamaster is right--that much powder inside the reg ought to damn near clog the filter at the inlet. Good luck on your investigation!!

 

[beachnik]

@ DA Aquamaster...

Aaah, of course. I noticed the groove in the schematic and didn't put 2 & 2 together.

Thanks for that, I might have somehow continued to overlook it as I proceeded.

@ everyone ...
The aluminum oxidation thing makes a lot of sense. All of those 60 dives were in Cozumel. I think there is one filler commonly used by just about all the dive shops. I've read some interesting stories here about what people have observed with Nitrox in Cozumel (percentages not being correct). It might be a safe guess that the filler is not real careful about tanks. Anyway, I'm going back down there in a month and will mention it to the dive shop operator.

I pulled the filter. It's got some green spots, but to my untrained eye, it doesn't seem to be plugged with particulate matter. I inverted it and tried to shake particulate out - nothing.

I grabbed my MK10 (it has a new filter) so I could compare it's filter with the filter in this MK10+. Interesting - the MK10+ has a much coarser filter. I can't imagine that the MK10+ filter is so course that the the oxide just blew through it without plugging it up (?).

These photos are of the MK10+ filter.

 

[Mpscubatoytech]

To me it looks like the lube that was used has dried out making the dust its normal in dry places like NM CO NV UT I have seen it a lot because the tech used to much or did not clean well as for the filter ever year scuba makes a new filter and change it a little for the tech to see if the customer comes ever year for service.

 

[halocline]

I'm pretty sure the white stuff was applied to the threads when the reg was last rebuilt. If it were something from the tank, it would be all over the seat and top of seat carrier. Your filter is definitely due for changing. It looks like it's an older style, I have not seen one like that. Is your reg DIN? Or is it just the difference in light in the photos of the filter? It looks a lot darker (more crud) on the outside, which would indicate that the filter is installed nose out. But your fingers look a lot darker in that photo too, so who knows.

Anyhow, I don't think the white stuff has anything to do with your IP problem. Once you get the piston out, inspect the edge with a jeweler's loupe and some bright light. If you see scratches, dings, or imperfections on the edge, there's your problem. You can try to polish them out with something, put in a new seat, and check for creep.

 

[chrispete]

Salt crystals?

 

[DA Aquamaster]

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.

 

[halocline]

So the filter on the right is the current one? That looks like the one the OP has. I guess that goes to show you; it reminds me of the old DH filters, that's why I thought it might be an older type.