|
Post by vance on Nov 30, 2017 21:55:28 GMT -8
Phil, the E-Bay MR-12 is a great regulator. I hope someone pickes it up, but I have enough now with the MR-12III. The MR-12 doesn't have that air blast that you object to, as the air routes internally like the Healthways Scubair you like. But it has a larger exhaust than the Scubair. John I already have an MR12, so no need for another. I'm working on it now. I got it recently because the auction also included a yoke with a fitting that I need to make another Y valve adapter for two regs. There was also an SPG I wanted and the price was right! So I got the MR12 as an extra. I need to take this one and my 2 MR12 IIIs to the LDS and get some recall diaphragm goodness! I guess they need to be a Mares dealer?
|
|
|
Post by SeaRat on Dec 1, 2017 0:20:01 GMT -8
Phil,
They need to be servicing Mares regulators most probably to get the diaphragms. My LDS was a Mares dealer, but decided not to be anymore. They still had the diaphragms. Whichever dive shop you use, they will need to take the serial number of the regulator that they replace the diaphragm on, and they will probably collect the old diaphragm to send to Mares.
John
|
|
|
Post by SeaRat on Dec 1, 2017 15:55:12 GMT -8
I have a few more observations about the Mares MR-12 III. The U.S. Navy Experimental Diving Unit made a recommendation to Voit/Mares to increase the exhaust non-return to a one-inch diameter. Mares did not do that. Instead, they looked at the exhaust rubber tee. The MR-12 and the MR-12 II had the same exhaust tee. But the MR-12 III has an enlarged opening on either side for greater air flow. I kinda feel that the engineers looked at the design, and said that there was nothing wrong with the size of the exhaust mushroom valve opening, but rather that the exhaust tee itself was inhibiting air flow. So it is quite a bit larger, and re-designed.
I just did some calculations after measuring the exhaust tee openings of the MR-12/MR-12 II and the MR-12 III. Guess what? The exhaust tee openings of the MR-12 III are more than double that of its predecessors. Here are the calculations:
MR-12/MR12II
Length = 3 cm Width = 0.8 cm Area (A) = Length (L) x Width (W)
A = W x L A = 0.8 cm x 3 cm A = 2.4 cm^2 2A = 4.8 cm^2
MR-12 III
L = 4 cm W = 1.5 cm A = 1.5 cm x 4 cm A = 6 cm^2 2A = 12 cm^2
As you can see, the MR-12 III has two and a half times the area in the exhaust too as it's predicissors.
I doubled the area because there are two openings, one on each side. But this only applies when the diver is level and head-down. In other positions, there will be unequal water pressures on the two ends of the exhaust tee, and only one side will exhaust until the exhalation pressure from the diver's exhalation exceeds the water pressure differential between the two sides of the exhaust tee.
I also have pressurized my "new" MR-12 III, and it has held pressure with the air shut off for times from 2 hours to overnight. I am pretty confident in its ability now to take to the open water.
John
|
|
|
Post by spirou on Jun 28, 2024 21:42:22 GMT -8
Hello ,
I just bought a MARES mr12 III. This regulator is the first regulator from Mares after after the AMF period. When Voit/swimmaster, stop to be involved in diving, Mares could save or keep the knowledge and continue the development of the mr12 family. In Europe Mares had distribute since 1970, Voit/ Swimmaster regulator. In the mares Catalog we found the titan and the mr12.
Regarding part list in manual, the second stage mr12 II , Mr 12 III are identical, the abyss and voltrex box use the same diaphragm as mr12 series. So first mr12 until abyss, same diaphragm.
Fred
|
|
|
Post by spirou on Jun 29, 2024 12:33:57 GMT -8
|
|
|
Post by spirou on Sept 5, 2024 22:00:20 GMT -8
Hello, Few weeks ago. I purchase a little mr12III, I made a complete maintenance, and a little test dive. IMG_5571 by Patrick Michel, sur Flickr IMG_6214 by Patrick Michel, sur Flickr The regulator was in good state, and after a cleaning, it performed really well. The deflector in the second stage give a strange feeling, it like the air arrive on one side of the mouth. This feeling is much bigger with some VIPER. Ten minute after the beginning of the dive, I forget this strange feeling. Fred
|
|
ggdive
Regular Diver
Posts: 14
|
Post by ggdive on Sept 6, 2024 15:58:32 GMT -8
Good to see someone else has experience with the Mares MR12 III. I have one as well which is in the queue to rebuild as well. I have a few regulators ahead of that one. Just finished rebuilding a Conshelf Supreme, what an easy breathing regulator that is. I have two of them from 1980. It is no wonder why they are still being used by the Military and professional divers. I think I like it better than my Atomic M1 and B2 which are suppose to be the easiest breathing regulators ever. But more importantly the thing about the MR12 is that it basically is the Voit MRII which was the first regulator with the Venturi tube added and was the first single hose regulator fully approved by the Navy for active use. That is what triggered the demise of the Double Hose regulator. Shortly after that I bought a Brand new one in the early 70’s but never got to use it and to this day I still have not found it after many moves later. It would be nice if it showed up but I doubt it will.
|
|