Scubapro Mark 10 question

[squidster]

I currently have a D300 second stage that has been serviced,iam thinking about purchasing a MK10 first stage.
my question is will this regulator be a good deep water reg, how does it do in colder temps?( non ice dives)
and is it still easy to get serviced?
when i learned to dive,the dive shop used MK10 in there classes.i thought they were great regs at the time.
from everything i have read the current mk25 is for the most part the same reg.
how does the mk10 compare with the mk25?
i dont see why if the MK10 is serviced why i coudnt use it in about any sitiuation as a new reg.
need some confidence building from the Board.

 

[Damselfish]

I still dive my original MK10 and have never had an issue with getting it serviced.

 

[Walter]

There is no better deep water reg.

 

[Blacthorn]

I use a Mk10 with a D400 and just love it. The combo, IMHO, is just as good as anything ever made, so yes you can use and will not have problems. If you are concerned with the chilly temps just have the environmental seal used. (the chamber is filled with Christolube I believe it is called.)

 

[halocline]

DA Aquamaster will hopefully chime in on this with the exact differences between the MK10 and MK25. The MK25 has higher flow rates, although this difference is essentially useless because the MK10 flows enough to fully supply two high performance 2nds on full purge, and the tank valve is likely to be the limiting factor in either case. The MK25 also is designed to deal with higher supply pressures, around 4500PSI if I remember right. It does this by using a set of bushings around the HP o-ring. Using the correct o-ring on the MK10 prevents any problem with hp extrusion at typical supply pressures, and of course the yoke is the limiting factor for supply pressure anyway, so this difference is only meaningful in HP DIN situations.

I have a feeling that one of the main reasons SP went to the newer bushing set up on the MK15, 20, and 25 was because the patent on the MK10 design ran out, and to a certain extent to aid "less than brilliant" techs who were not up to the care that is needed in removing and replacing the MK5-10 hp o-ring.

 

[squidster]

DA Aquamaster will hopefully chime in on this with the exact differences between the MK10 and MK25. The MK25 has higher flow rates, although this difference is essentially useless because the MK10 flows enough to fully supply two high performance 2nds on full purge, and the tank valve is likely to be the limiting factor in either case. The MK25 also is designed to deal with higher supply pressures, around 4500PSI if I remember right. It does this by using a set of bushings around the HP o-ring. Using the correct o-ring on the MK10 prevents any problem with hp extrusion at typical supply pressures, and of course the yoke is the limiting factor for supply pressure anyway, so this difference is only meaningful in HP DIN situations.

I have a feeling that one of the main reasons SP went to the newer bushing set up on the MK15, 20, and 25 was because the patent on the MK10 design ran out, and to a certain extent to aid "less than brilliant" techs who were not up to the care that is needed in removing and replacing the MK5-10 hp o-ring.

Is the MK10 designed to take up to 4000psi with yoke?

i hardly ever have my tank filled past 3200psi , its a 3000 psi tank.

 

[DA Aquamaster]

The potential issue with the Mk 10 is that if you have one withloose tolerances or what that is well worn with a larger than origiinal clearance between piston stem and first stage body, the High Pressure o-ring can get forced into the gap at high pressures and get little pieces snipped off as the piston moves back and forth. This results in litle cresent shaped cuts in the oring and eventually causes a leak.

On this case high pressure usually means more than 3500 psi as the Mk 10 was designed for service in the 3300 psi range.

THe Mk 15 was designed to be easier to service(but was not) and the Mk 20/25 really was easier to service. But the real motivation to add bushings to the Mk 15,20 and 25 was to allow the tolerances to be retsored annually and to eliminate wear on the reg body. The Mk 15, 20 and 25 are consequently rated to 4350 psi.

The Mk 10 yoke is rated to 3300 psi but it large enough that 4000 psi would probably not be an issue - but again HP o-ring crimp would probably be a problem.

 

[redacted]

The potential issue with the Mk 10 is that if you have one withloose tolerances or what that is well worn with a larger than origiinal clearance between piston stem and first stage body, the High Pressure o-ring can get forced into the gap at high pressures and get little pieces snipped off as the piston moves back and forth. This results in litle cresent shaped cuts in the oring and eventually causes a leak.
.

And well before this "nibbling" occurs, the extrusion will cause increased friction between the piston shaft and the o-ring resulting in IP increase with increased tank pressure. I have one Mk10 that I just replaced the HP piston o-ring with a V90 and it is producing an IP of 125 @ 500 psi and over 135 @ 3000 psi. But I'm hoping to cure the problem by replacing the Viton o-ring which does not have the best dynamic characteristics (includes resistance to extrusion) with a polyurethane o-ring which has excellent dynamic characteristics. So there may be ways to manage that potential problem if it is not too bad.

 

[diver 85]

Is the MK10 designed to take up to 4000psi with yoke?

i hardly ever have my tank filled past 3200psi , its a 3000 psi tank.

I bought my MK10 in about '89 or so and recently used it on hp 120's with about 3600psi.....no problems to date......

 

[squidster]

The potential issue with the Mk 10 is that if you have one withloose tolerances or what that is well worn with a larger than origiinal clearance between piston stem and first stage body, the High Pressure o-ring can get forced into the gap at high pressures and get little pieces snipped off as the piston moves back and forth. This results in litle cresent shaped cuts in the oring and eventually causes a leak.

On this case high pressure usually means more than 3500 psi as the Mk 10 was designed for service in the 3300 psi range.

THe Mk 15 was designed to be easier to service(but was not) and the Mk 20/25 really was easier to service. But the real motivation to add bushings to the Mk 15,20 and 25 was to allow the tolerances to be retsored annually and to eliminate wear on the reg body. The Mk 15, 20 and 25 are consequently rated to 4350 psi.

The Mk 10 yoke is rated to 3300 psi but it large enough that 4000 psi would probably not be an issue - but again HP o-ring crimp would probably be a problem.

So as long as the first stage is servisible i can trust it to work fine.
a scuba pro tech would most likely tell me if it cannot be serviced or if the reg is a little loose.