B2 regulator piston & IP creep

[Johnoly]

This is just a fun post, nothing much to learn and really a 'show & tell' if you just want to skip to the pictures below instead. I don't rebuild my B2 regs myself and I leave it to a couple of techs when my IP starts slowly creeping from 135 up to 150. Then I'm swapping to another B2 reg set until my favorite primary can get rebuilt. In the last couple of rebuilds, instead of the IP lasting 250 dives at 2 years, I was only getting about 125 dives & 1 yr til the 'Creep' showed up. Scotch pad buff & cleaning sometimes just won't work on scratches. I had read and watched @rsingler 's videos on polishing B2 pistons to get it to IP lock up. But if you put some new seats/orings/parts and slather it in grease, it will IP lock up for a hundred dives until all those imperfections dig in and the 'creep' returns. Even though the shaft Orings don't have a lot to do with IP lock up, that many gouges isn't helping it much either by trapping crud.

Here is the magnified picture of the18yr old 1st stage piston(uncleaned) and you can see the tiny little nicks that hide the underlying problems. It's just old & worn out even though serviced bi-annually. Took a few weeks to get a new piston shipped in, but the old worn out one is gone. Again, not much new to learn, but an interesting “show & tell” picture story.

 

[Mobulai]

Damn! Is that black streak a reflection or a deep score? Or screeched oring?

I’m doing/attempting a similar piston recovery for a friend (mk20s) and was thinking of doing a similar show and tell — but it’s more of corrosion and sand eating at the reg as a whole (the friend is am instructor, he got these 2 regs from his dad, also an instructor)

You can see one of the culprit grains of red sand stuck to one of the pistons; that ambient chamber is cooked

These mk20s might be ready for retirement tho; will see how long IP holds before they go on the shelf

 

[Johnoly]

..and was thinking of doing a similar show and tell

None of my techs owns a microscope, just jeweler's loupe and scope's are so cheap on ebay. Like you mentioned, my piston to the naked eye looks ?acceptable?, but it's really worn out when seen 'up-close'.

Your picts are great also. Without people showing examples of hard-to-see problems, I would have never learned what to ask to look at when my reg was being disassembled for cleaning. Keep posting close-up pictures and pointing out the failure & why it matters so divers know who the good techs are !!

 

[Mobulai]

Here is a couple after cleaning pictures of the ambient chambers, lots of bare brass and deep vertical scratches (reflections aint helping)
Looks like a nuclear wasteland

30 years of (almost daily diving) the red sea can be very taxing
Probably the last season for this set

Edit: funny the older gen mk20 (with smaller holes) had way less damage than the newer one with the composite piston

 

[Johnoly]

Looks like a nuclear wasteland

Great inside pictures of all the imperfections. It's going to take a great Tech to show the customer the pictures and explain that sometimes it just won't last that long even if it's rebuilt.

 

[Mobulai]

Great inside pictures of all the imperfections. It's going to take a great Tech to show the customer the pictures and explain that sometimes it just won't last that long even if it's rebuilt.

Luckily (as I’m not a great tech, but had a great teacher), the customer is a friend, and he has maybe 10 other sets so he knows it’s their winter years
This is more of a last hurrah to honor the regs he got from his dad before hanging them up (maybe scavenging some internal parts if in a pinch, they are mk20 obsessed )

 

[BoltSnap]

30 years of (almost daily diving) the red sea can be very taxing
Probably the last season for this set

I wonder if he got his money's worth out of this reg.

 

[Mobulai]

I wonder if he got his money's worth out of this reg.

Either they owe Scubapro some money on the extra milage, or SP owes them some marketing proceeds

 

[The Chairman]

I used to use an electric eraser on Cousteau knife seats to solve this problem. They were a diaphragm reg, but boy did it polish them clean. That or buy a new piston.

 

[BoltSnap]

Either they owe Scubapro some money on the extra milage

Please, pretty please, don't give ideas to Scubapro; they may start charging us per dive if we go above a certain number of dives