Something new - Scubapro Mk10

[Genesis]

I just saw something that I thought was quite odd in a Scubapro Mk10, and wanted to run it by people here...

I picked up another "older" one off eBAY, with a G250HP and an Octo. Nice deal overall.

As is my usual, I tore it down on arrival to check it out and go through it - its my butt, 'ya know.... new O-rings and such are the order of the day.

Anyway, the HP seat was a design I had not seen in these regs before. It was a hard white nylon puck, with a number "2" on the back of it, and no O-ring around its bore to locate and seal it in the end cap.

The existing seat was fine, so I reinstalled it and went on my way...... the reg is working great.

ALL of the seats I've seen thus far in Mk10s have had a groove for an O-ring between them and the seat cap, and an O-ring for a seal there. This one didn't. It was a conical seat, the "newer style", and the IP was rock-nuts on and stable.

Anyway, I was wondering if anyone had any idea what the deal is with that..... if it turns out that this is an aftermarket part then I'm even MORE interested, as I want to try to run down the source of those seats!

 

[DA Aquamaster]

Scubapro used the seats you describe in the mid to late 90's (I still have several parts kits of that vintage.) There was alos an older flat seat design that could be reversed. Not sure when this was phased out but TUSA used it on their MK 10 copies until they went out of production. They are not conical but are quite nice as they can be reversed when one side wears out.

The latest and greatest generation of MK 10/ MK 10 Plus HP seats from Scubapro are in my opinon far less reliable and durable than either of the older designs

 

[Genesis]

the new ones bite compared to the old ones

Of course all you can get is the new ones....

Oh well, this one is still seating just fine, and its staying in there until its not any more.

I wonder if someone would be interested in making up some of these puck-style seats from an appropriate compound.... they'd have to be plenty cheap in quantity, with nearly all of the cost being setup.

That'd do it for "unobtanium" parts for the SP regs; I have successfully found O-rings (in EDPM at that!) for all their other stuff, and thus don't need their "kits" for anything other than seats any more for routine stuff.

 

[redacted]

Genesis once bubbled...
I have successfully found O-rings (in EDPM at that!) for all their other stuff, and thus don't need their "kits" for anything other than seats any more for routine stuff.

Karl,

What are you using for the Poppet stem o-rings on your S600? I think that is the only one I have not been able to find a satisfactory match for.

I noticed a Mk10 service kit on ebay a couple week ago with a picture that seemed to show 3 seats. All looked to be about the size of the Mk5/Mk10 puck. With the SP philosophy of design compatability, I was surprised to see that.

 

[Genesis]

I have service kits (still) for my S600

I'm working on those shortly - they're due to annuals here shortly, so I will get to play with that one....

I don't know if I will be able to match those or not, but I intend to attempt it

 

[Zaphod]

The three seats allow adjustment of the IP. In each one the height of the concave surface is varied and the shorter it is, the higher the IP. They should be marked with +, -, and = with (+) being the shortest and (-) the longest. These seats can be a bear to get out, and can be destroyed in the process. The small hole on the end of the cap is there so you can force the seat out with your airgun. To make sure it comes out easily for the next guy, put a little grease around the outer edge of the seat. I'll thank you for it...

The Mk10+ uses the seat with an o-ring and is generally "flippable."

 

[neil]

Zaphod once bubbled...
The three seats allow adjustment of the IP. In each one the height of the concave surface is varied and the shorter it is, the higher the IP. They should be marked with +, -, and = with (+) being the shortest and (-) the longest. These seats can be a bear to get out, and can be destroyed in the process. The small hole on the end of the cap is there so you can force the seat out with your airgun. To make sure it comes out easily for the next guy, put a little grease around the outer edge of the seat. I'll thank you for it...

Hmm, I could be wrong but....
I would be afraid that if you greased the seat, you might find out one of the rare ways a piston reg can stop giving air: by having the seat stick to the piston as it's pulled away out of place. There's a good reason why the seats are force fitted in.
I was always told that the small hole is there to prevent the seat from moving toward the piston if air got behind it. Not that I'd argue with an engineer, mind you.

Neil

 

[Zaphod]

The primary mechanism for keeping the seat in place is not friction, but a crushable washer placed between the seat and the regulator body. With this washer in place, there is no way the seat will pop out even if it is well greased. That said, the hole in the plug actually serves two related functions: one is to allow the seat to be installed fully by allowing trapped air out and the second is to help get the seat out later, as described before. The washer also helps to provide the air-tight seal so an o-ring is not required around the seat (like in the Mk10+).

It's also generally not much of a forced fit to put the seat in. It usually just slides in, but frequently it doesn't just slide out. If it hasn't been greased during the previous rebuild, then the only effective way to get it out is to screw in a sheet metal screw (or similar) so you then have a handle you can use to pull it out. Yes, I know that idea will make some people cringe, but this is what SP tech support recommended to me the first time I couldn't get one out.

 

[buddhasummer]

The three seats allow adjustment of the IP. In each one the height of the concave surface is varied and the shorter it is, the higher the IP. They should be marked with +, -, and = with (+) being the shortest and (-) the longest. These seats can be a bear to get out, and can be destroyed in the process. The small hole on the end of the cap is there so you can force the seat out with your airgun. To make sure it comes out easily for the next guy, put a little grease around the outer edge of the seat. I'll thank you for it...

The Mk10+ uses the seat with an o-ring and is generally "flippable."

Just in case someone else stumbles across this thread, a correction to the above post. My understanding is the + is the shortest (highest ip) and the = is the longest (lowest ip), the - is in the middle. Cheers.