strange creamy paste on MK25

[gimbo]

Dear all,

Yesterday I fixed the IP pressure of my two MK25s and, only on the more recent (not yet overhauled) of the two, I find a strange creamy paste between the adjustable screw and the seat retainer and under the seat retainer too.

It does not look to be christolube....it is more dense and with a pale yellow colour.

Is it there to water proof the thread?
What kind of material is it?

Paolo

 

[Couv]

Hello Gimbo,

I see this is your first post here. Welcome to Scuba Board.

It seems you are already familiar with the cookie dough that is sometimes left behind by Christolube when the oil separates. I think it unlikely a patina would form and mix with the grease to give you that color. My best guess would be a different grease, such as Parker Super-O-Lube, which has a yellow/gold color was used.

This might be a good question to ask the experts in these sub-forums: (You should consider sending the "owners" of those forums a PM as they don't log on very often.)

Tribolube - ScubaBoard

or

Christolube - ScubaBoard

I would be interested to hear the answers.

Couv

 

[halocline]

Sounds like Hollandaise sauce to me.

 

[Couv]

Matt my friend,

I'm getting concerned about you. Please consider backing away from your diet a little. First it was o-ring morsels eaten with chopsticks, now eggs benedict with Parker lube.....find a big ass cheeseburger for supper tonight.

c

 

[Texfrazer]

Careful couv,

He'll be calling things "special sauce" next.

 

[gimbo]

a picture of the seat retainer with the screw and the spacer all covered with the strange creamy paste...

can be oxidized christolube?

 

[Jim Lapenta]

Either that or fish sperm.

 

[Couv]

Well, from your pix, it does look like someone got very carried away with the ChristoLube. The yellow tint in it may be a bit of corrosion, which is very surprising considering all the lubricant in that area. However, ScubaPro did make a modification to address the possibility of water droplets entering through the threads between the seat retainer and the adjustment screw. See bulletin #274. If you need a copy, PM me with an email address where you can receive a PDF file.

At any rate, I think a good clean up, and lightly lube (if any) those threads, and install the modification I mentioned earlier which involves the installation of an o-ring and washer.

Good luck and keep us posted,

Couv

P.s. On the other hand, Matt may have owned this regulator and put mustard on it. "Pardon me, would you have any Grey Poupon?"

 

[TRIBOLUBE71]

Couv,

You hit the nail on the head with your answer of corrosion. The grease in the picture is MCG129, the only grease currently used in assembly. There is a corrosion inhibitor in this grease that (for lack of a better scientific description) by means of an amine to acid etch the surface in order to form the protective barrier.
Passivation from the corrosion inhibitor should form a protective layer on the metal surface through physical or chemical absorption. The inhibitor is most likely a chain with a polar group to interact with the metal surface.
When the oil is absent the part is no longer protected from O2 and H2O , and potentially salt acid now corrosion occurs.
The discoloration I believe is in fact Fe2O3 or rust. The areas that are discolored are more likely to continue in this process.
Whoever serviced this reg put too much grease in there. For several reasons. trying to compensate for the history of oil loss and residue buildup-without oil the lubricity dramatically is reduced in dynamic applications. Another possible reason is an attempt to make it to the next servicing. By using a more efficient thickening matrix to hold the oil in place slowing syneresis (liquid separation: the process by which a liquid is separated from a gel owing to further coagulation) from 3000psi of pressure.This would keep the grease structure homogenous not thickened like scale or cookie dough caused by massive oil loss. A more effective grease will decrease WOB and positively affect cracking pressure to reduce fatigue and increase bottom time.

Well, from your pix, it does look like someone got very carried away with the ChristoLube. The yellow tint in it may be a bit of corrosion, which is very surprising considering all the lubricant in that area. However, ScubaPro did make a modification to address the possibility of water droplets entering through the threads between the seat retainer and the adjustment screw. See bulletin #274. If you need a copy, PM me with an email address where you can receive a PDF file.

At any rate, I think a good clean up, and lightly lube (if any) those threads, and install the modification I mentioned earlier which involves the installation of an o-ring and washer.

Good luck and keep us posted,

Couv

P.s. On the other hand, Matt may have owned this regulator and put mustard on it. "Pardon me, would you have any Grey Poupon?"

 

[gimbo]

Sure that is not the Weicon anti seize "hi-tech"?