Well, interesting afternoon with some, anyways. Jay and I spent a lot more time in the car than working on MR12s. We met up with CJ at our favorite Russian Louisiana-style BBQ restaurant and had lunch, then went to the Breakwater to look at the water and take some regs apart on the tailgate of CJs Tacoma. Not optimal, but not the worst place I've service a regulator.
I took one of mine apart and inspected it under the very watchful eye of JB, and Jim went to school on me. I attacked the dreaded o-ring with a bit of trepidation, but got the little sucker in without too much bad language. It got put back together, hooked up, and IP set. Works. I should probably replace the seats.
CJs reg then got the teardown. His was more corroded than mine, and needs a dip in the vinegar. It went home in a body bag.
I have finally gotten around to re-assembling my MR-12 (serial number 46327). I am awaiting the rebuild kit that I just ordered and the pieces and parts are in a vinegar/water soak. While I was sorting through my stash, I found another one marked "Titan II, MR-12 in need of an exhaust diaphragm. Now I must find the assembly diagram (again).
After re-reading Greg Barlow's post, it appears that I have an early model (Titan II) and a late model (serial number 46327) MR-12. I can hardly wait to try out my chicken-like, close motor skill on these. By the way, thanks to Jaybird I was able to easily remove the exhaust tee's via his hot water soak method. Thanks Jay!
"Did Phil mention his recent conversion from vintage horse collar to back mounted wing with power inflator? "
Yep. It's true. And will probably never go back. Soooooo much better and easier. The vintage part of my rig is the tank, regulator, gauges, and most vintage of all, me.
I will always qualify as a vintage diver, no matter what! Or maybe even ancient mariner!
For a while in the 1980s I had the most unique, perhaps best, back-mounted BCD anywhere.
If you look at this photo, everything on my wetsuit in white is BCD. Bill Herter, of Deep Sea Bill's fame (now deceased, unfortunately) built custom wetsuits, and then the whole back of the suit was a sandwich of two 1/8th inch neoprene pieces with the outer edge sealed with 1/2 inch strip neoprene. An inflator hose was built into the top of the wet suit too. This was the most comfortable, and streamlined, back-mounted BCD ever built, iMHO.
This back-of-wetsuit BCD allowed very fine tuning of the buoyancy, and was a completely balanced system.
By the way, I love my MR-12, and use it on my Trieste II as an octopus. The MR-12, MR-12 II, and MR-12 III are very good regulators.
Certainly unique. I think that a “u” shaped bcd would work better than the “donut” shape currently in use because the bouyancy would be at the midpoint of the body. Now, back to the MR-12. Would someone please post a video on how to rebuild these regulators? Phil, I have seen you take one apart. A video would be very helpful.
Post by technidiver on Mar 20, 2019 15:15:39 GMT -8
I used pliers to get the HP Valve out. Just s pair of needle nose pliers with tale on the teeth and then I gave it a firm twist and poof it can't out. The MR12 definitely has a couple quirks in its design that make it tougher to assemble than another diaphragm reg. The Conshelf and Dacor 400/800 are my favourite diaphragm regs.
"If not now, when? If not us, who?" John F Kennedy
Using the tool is no problem, just insert the pins in the holes and turn CCW to remove the HP assembly. No need to torque it down hard when you reassemble, the oring does the sealing, not how tight it is. The balance chamber oring is the PITA.
I was looking through the illustrious box of junk I picked up. There are 2 MR12 second stages in there. They appear to be complete except for the diaphragm. Maybe I need to find a first stage. One cool thing about them is the serial numbers are 12028 and 12030. I think its cool they came off the line almost together and they are still together
Skip, if you do get a first stage for them, get the newer one with the upgraded yoke and 3rd LP port: the Scubamaster uses the very same first stage:
If you don't know already, the original type of diaphragms on them can be dangerous because they cut corners and didn't rivet them in and will delaminate pulling the friction plate away. But, if that does happen, you can use the diaphragm to make an exhaust horn diaphragm for a model-A (original) scuba