Regulator Geeks: Scubapro Mk19EVO - teardown & discussion

[bethunec]

Thank you for the sharing Robert.. I ordered the MK25T and 620TI from SB for me and my wife but I haven't pick it up yet.. due to light weight and longevity.. but now I am having second thought.

 

[rsingler]

The Mk25 is the most popular first stage in the world. So I'm swimming against the current here.
An unsealed piston will last 30 years with proper rinsing.
But I'd like mine to last forever.

 

[mictrik]

Tomaytoe...tomahtoe.
Yes, it happens.
New'ish Mk25 from yesterday's service bench.
Note the vertical scratches and chrome loss in the piston head land.
View attachment 705470
Old'ish Mk20 that someone wanted preserved after 30 years. Note the completely absent chrome and heavy scoring.
View attachment 705472
Does it happen? Is it real? Yes.
Is it fast? No, and yes. Depends upon rinsing.
Does it affect sealing? Only in the worst cases.
The Mk25 double o-ring seal with a wiper o-ring protects the actual seal to a great degree.
Does the Mk25 deliver the highest flow of any first stage reg in the world? Probably.

Out of sight, out of mind.
But if you know it's happening (i.e., if you service your own gear), it makes you crazy.

Well, it makes me crazy.

Lol!

 

[Geo7]

Thank you for the sharing Robert.. I ordered the MK25T and 620TI from SB for me and my wife but I haven't pick it up yet.. due to light weight and longevity.. but now I am having second thought.

With titanium you have less of a problem, as the intitial abrasion won't corrode further. Also, the Mk25 has a wiper o-ring and bushings to protect seealing areas, but it needs to be rinsed religiously. And keep in mind we are referring to quite sandy water. For places like tropical vacation diving, or the Mediterranean in Europe, a Mk25 (even non T) can last a really long time. Rinse and enjoy.

I totally agree with Rob though: I have serviced unsealed Atomics that needed piston restoration due to abrasion and corrosion, and seal mine with Tribolube for SoCal diving.

 

[drakcheslav]

I was on the brink of ordering Mk19evo/g260 kit for sidemount. But my instructor dissuade me to get an mk25evo/g260 since w mostly dive fresh water, with once or twice a year salt water. Lowest temps 4C, and that's not that limiting.

Also, I'm pretty thorough with my regulator rinsing and drying.

It's not silty or grimy water. He said that for our conditions, a piston with treatment for cold water would be best. Since it's easier to service and longer life.

After I found this thread I'm glad I made the switch.

 

[BoltSnap]

I was on the brink of ordering Mk19evo/g260 kit for sidemount. But my instructor dissuade me to get an mk25evo/g260 since w mostly dive fresh water, with once or twice a year salt water. Lowest temps 4C, and that's not that limiting.

Also, I'm pretty thorough with my regulator rinsing and drying.

It's not silty or grimy water. He said that for our conditions, a piston with treatment for cold water would be best. Since it's easier to service and longer life.

After I found this thread I'm glad I made the switch.

What advantage does the MK25 have over the MK19 from your point of view for you environment?

 

[drakcheslav]

What advantage does the MK25 have over the MK19 from your point of view for you environment?

According to him ease of service and simplicity, for the same package I'm getting a whole sidemount set.

Mk25 is an older more established rehulator. And since servicing here is Serbia is not as easily available, he recommended me to go with a piston. Mainly less complexity and more reliability.

I'm not saying thay mk19 is not realiable. But he recommended i go with a piston based on his servicig experience of his club regulators. He's been a long apeks user, and he's quite disappointed with them in the long run. And he's thinking of switching to cold water piston regs for future club regs.

We dive clear non poluted regs. Most of the "low viz" is due to plancton. Also the caves that we have are not as silty. And the Mediterranean is quite clear. No sandy siltu water.

 

[BoltSnap]

here is Serbia

Do you have access to the Mediterranean in Serbia?

 

[drakcheslav]

Do you have access to the Mediterranean in Serbia?

6hrs drive to Montenegro.

Our scuba club spends half of the year in Montenegro, and Greece is also 6hrs away.

A lot of divig here. We basically dive every week here in lakes/rivers. And spend the summer at the Mediterranean.

 

[Bald Wookie]

6hrs drive to Montenegro.

Our scuba club spends half of the year in Montenegro, and Greece is also 6hrs away.

A lot of divig here. We basically dive every week here in lakes/rivers. And spend the summer at the Mediterranean.

This almost looks like an invitation…