Used quality on MK10
- Thread starter scubareporter
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Hank49
Contributor
my daughter uses an MK10 with a G200 she bought used 10 years ago. We just opened it up and it looked clean inside. Greased the o rings and went diving.
if you're looking for a new 1st stage, I just bought an S555 ScubaPro, which is the new G200 I guess. It's an S600 with no adjustment knob. It breaths just like my Atomic.
if you're looking for a new 1st stage, I just bought an S555 ScubaPro, which is the new G200 I guess. It's an S600 with no adjustment knob. It breaths just like my Atomic.
OP
scubareporter
New
Thanks again to all. I have it now, taking it to a pool to check it out. It looks good, no dents or anything visually wrong with it. the second stage is old school, not sure of the model. I guess it was the same as the Navy used back in the late 90's. I has a beat up Suunto computer and console, needs new battery, otherwise operable. Presure gage and compass look good. Great for a first time set up I think, also will be good as a back up if I get new stuff for christmas. Thank you for your time to give me your input.
mobeeno
Contributor
It is not so much that you can't use the Mk 10 at higher than 3,000 psi,I have used one with 3200-3300 psi tanks many times, the issue is a matter of potential o-ring extrusion and wear requiring more frequent service and/or higher failure rates. For that reason I don't feel it is a good choice for those that will be frequently using them with high pressure tanks. Don't get me wrong, I think the Mk 10 is a great warm water regulator design, I just spent most of a week diving with one after running into trouble with my Mk 20 on one of my first dives of the trip.
One word of warning regarding opening up and working on the Mk 10, if you remove the piston, it is difficult to reinsert it without a protective piston bullet, as the sharp edge is prone to nicking the trapped O-ring This is probably the most common mistake made by people that don't know what they are doing when attempting repairs.
halocline
Contributor
You're talking about 2nd stages, not 1st stages. (I'm sure that's just a typo) The S555 would be a little more like the G200B, which is probably a G200 with the balanced poppet/seat/spring arrangement. (I've never opened up a G200, but I have worked several G200Bs)
Actually there was the G500, which was more of a predecessor of the S600 than the G series. It has the smaller case. I have an excellent condition G200B and I would not trade it for the current S555. The G200B is nice very light weight 2nd stage that lacks the adjustor but still has the full size case and metal air barrel.
halocline
Contributor
The atomic is a descendent of the MK20/25 series, not so much of the MK10, although it is true that Atomic was started by former SP engineers. There are some pretty significant differences between the MK10 and later SP balanced piston 1sts, like the HP bushing system and rounded piston.
The MK10 in some ways is a little bit of an anomaly in the SP line of BP 1sts. To me the MK5 resembles the later models more; it has the bigger piston and the body fits together in a more similar way. The MK 10 has the body with the ambient ports on the main body (not cap) and the large o-ring that seals between the body and cap. I'm not sure what the reason was behind designing the body that way.
Hank49
Contributor
halocline
Contributor
It will say either G200 or G200B on the purge button. If it says G200, and you want to upgrade it to a G200B, you would need to replace the poppet, spring, and add the balance chamber. If your dive shop or whoever services your reg has an older stock G250 kit, the poppet and balance chamber come in the kit, and the spring is under $5. So it's a very inexpensive upgrade with a regular service.
A G200B should theoretically perform identically to a G250, as it is essentially the same reg except without the adjuster, and SP practice is to tune the G250 with the adjuster all the way out. The G200 could be set to have the same cracking effort, but theoretically will require a little more effort to keep air flowing as you're working against a stiffer spring. In practice, there is a much wider range of performance based on how well the regs are tuned than there is difference between the models themselves. The same thing is true with the older metal case 2nds. A well tuned 109 (unbalanced) will breathe much better than a poorly tuned 156.
A G200B should theoretically perform identically to a G250, as it is essentially the same reg except without the adjuster, and SP practice is to tune the G250 with the adjuster all the way out. The G200 could be set to have the same cracking effort, but theoretically will require a little more effort to keep air flowing as you're working against a stiffer spring. In practice, there is a much wider range of performance based on how well the regs are tuned than there is difference between the models themselves. The same thing is true with the older metal case 2nds. A well tuned 109 (unbalanced) will breathe much better than a poorly tuned 156.
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