MK 2 clone?

[Ed Palma]

First of all, I've always been a diaphragm reg kinda guy... that is, until now.

Few days ago I purchased 2 unbalanced generic piston regs, just to get their din wheels to use on my main regs (DIN assemblies were around 70 dollars, the regs were just around 67...). my LDS had them on consignment, so they weren't too sure about what parts could fit into it. I told them I'd take pictures after I took it apart.

Now, I've seen and read about the simplicity of a piston reg, but seeing the schematic and actually seeing how totally and utterly simple one is compared to a diaphragm reg is amazing.

Bulletproof indeed! (BTW the DIN assembly is not included in the photo. It is, uh... on another reg )

So... my question is: Does it look like a MK 2 clone?

 

[redacted]

Basically, all simple flow-by piston 1sts look like a Mk2 clone. You will find different diameter pistons (meaning o-ring and spring will be different), but most use the same HP seat. They should work fine on a pony or stage bottle or just about any other use you want including a primary 1st stage or a tire inflater.

 

[halocline]

Yep, two moving parts, the piston and the spring. No dynamic o-ring at supply pressure. It's a great example of simplicity.

The balanced flow through design is slightly less simple, but also an extremely economical design from a mechanical point of view. The big difference is the HP o-ring that separates supply pressure from ambient.

 

[Ed Palma]

They should work fine on a pony or stage bottle or just about any other use you want including a primary 1st stage or a tire inflater.

Slapped one of them onto my pony. Still scrounging around for another use for the extra reg. (my utility reg's a diaphragm for adjustability of IP)

Speaking of IP, how much increase in IP would one 1mm washer give? Right now, this piston reg locks up at around 140.

 

[redacted]

Slapped one of them onto my pony. Still scrounging around for another use for the extra reg. (my utility reg's a diaphragm for adjustability of IP)

Speaking of IP, how much increase in IP would one 1mm washer give? Right now, this piston reg locks up at around 140.

1mm is huge, don't use it. 140 psi is not bad with a full tank. It will drop about 10 psi as the tank pressure drops. I'll have to measure, but my recollection is that an adjusting shim (washer) is about .007 inches thick

 

[Ed Palma]

... I'll have to measure, but my recollection is that an adjusting shim (washer) is about .007 inches thick

Wow. I did the math, and that's like 0.177mm. Definitely a shim, and not a washer.

 

[redacted]

OK, I found a caliper. Looks like about .25 mm per washer.

 

[herman]

Basically, all simple flow-by piston 1sts look like a Mk2 clone. You will find different diameter pistons (meaning o-ring and spring will be different), but most use the same HP seat. They should work fine on a pony or stage bottle or just about any other use you want including a primary 1st stage or a tire inflater.

So far I have found at least 3 different sizes of HP seats in various reg brands.....and another one (I think- have not had time to mike it) today. In any case, HP seats for pretty much any FB piston is fairly easy to DIY.

Doc you might want to check out this thread if you have not seen it. http://www.scubaboard.com/forums/regulators/339033-really-how-much-creep-problem-2.html

 

[Ed Palma]

Doc you might want to check out this thread if you have not seen it. http://www.scubaboard.com/forums/regulators/339033-really-how-much-creep-problem-2.html

Saw it early on, but it has definitely grown since I last saw it

Thanks!

 

[AquaNSun]

Doc, what brand was that 1st stage?