Mistril and banjo

[Mudhog]

Seems mine won't cooperate, my yokes just a tiny bit short, would there be a proablem making a stainless steel spacer to shim out the yoke retaining nut enough to make a stainless banjo work?
TIA!

[luis]

That should work OK. Just don’t make any thicker than necessary. You want the ring that compresses the valve O-ring sticking out enough that the yoke would never touch the sides of the valve.

If you need an actual dimension of how much it need to stick out I may be able to help you later, when I am at home.

Good luck.

[Bryan]

would there be a proablem making a stainless steel spacer to shim out the yoke retaining nut enough to make a stainless banjo work?
TIA!

I agree with Luis on this one, On the European Mistrals the yokes come in three or four thicknesses. Some work with banjos some not so much...I think you would be fine if you used a thin shim. Please tell let us know what you use and post some pictures if you can please.

[Mudhog]

Yes I had, but looked again to be sure (in refferance to the nice online guide about what tank valves work with banjos).
Tried several difftent old US Divers J valves, one almost let it go on, the rest not so much. Wonder if I have fallen victim to tollarance stack.
Yoke opening 1.020"
Putrusion of body from yoke nut 0.205"
Yoke nut head thickness 0.140"
US divers Santa Anna J valve with banjo 1.035"

I thinking reduce the putrusion to 0.100" or a yoke opening of 1.100" will allow me to us it on enough valves to be happy.

As a comparison the yoke opening of a Calypso III is 1.080"

Thing is the main reason I got the banjo was for use with the Mistral.

[Bryan]

The long yoke(harder to find) Mistrals work best with the banjo fittings. Sounds like you are on the right track though! Please let everyone know how it works out.

[Mudhog]

Okay, bored out a stainless steel washer on the old Southbend, screwed the Mistral back together, hooked it up with banjo to the only tank with preasure in the house, a Catalina al80 with a DIN valve. Opened the tank valve and it held, closed the tank valve and even with a hp hose that looks like it was swiped from the trash heap the retained preasure after half an hour only droped from 2800 to 2400. Yeah, I am happy.
BTW, to remove preasure on a double hose reg sans hose, I carefull stick a wooded chopstick through an exhaust hole and depress the center the the diaphram, kinda a poor mans purge button.

[luis]

Sounds good, except for the use of 2800 psi on a Mistral. My understanding is that the Mistral seat does not like that high pressure. The good news is that Bryan is now making reproduction replacement seats.

Even if it doesn’t damage the seat, the Mistral will perform very poorly with high tank pressures.

Can you post some pictures of your modification? It sounds like a reasonably easy solution for a number of Mistrals with short yokes.

[Mudhog]

Well Bryan rebuilt that Mistral for me, not sure the status of the seat.
Will be going to town tomarrow to the eye-doc, should have time to stop and see if any thicker washers are avaible. Could have made it from some stainless 1/2 pipe we have around but that was to small an outside diameter, might crush and allow slack, a very bad thing. Nicest option would be a replacement body washer that was thicker but that would run into real money, done as chrome plated brass.

[Bryan]

Well Bryan rebuilt that Mistral for me, not sure the status of the seat.

If I rebuilt it in the last 6 months the seat is a new reproduction of the original seat...If the problem lies there let me know and I'll replace it ASAP...

[WD8CDH]

Sounds good, except for the use of 2800 psi on a Mistral. My understanding is that the Mistral seat does not like that high pressure. <snip>

Didn't JYC use the Mistral at 5000psi?

[Mudhog]

Well Bryan rebuilt that Mistral for me, not sure the status of the seat.

If I rebuilt it in the last 6 months the seat is a new reproduction of the original seat...If the problem lies there let me know and I'll replace it ASAP...

Rebuilt in the last 6 weeks, very happy with the work and astounded by the quick turnaround.
No proablem here, because the tank valve was closed that preasure drop was just the air in the gauge, hose, adapter and hp section of the Mistral, thats a lot of surface area for a tiny bit of air, maybe 1/4 of a lungfull and it only lost a fraction of that and don't forget that hp hose is not one I would dive with either!
BTW the gauge must be an old one, US Divers orange face back stem marked C. P. G.

[Bryan]

Sounds good, except for the use of 2800 psi on a Mistral. My understanding is that the Mistral seat does not like that high pressure. <snip>

Didn't JYC use the Mistral at 5000psi?

He used LaSpirotechnique Royal Mistrals at that pressure. According to Ryan Spence they were not modified.

In speaking with Sam Lecocq at Portage Quarry this summer his thoughts were that using a Mistral at high pressures would not damage the seat but would cause it to wear more quickly..... That is wisdom from our elders that invented this stuff!!!

IMO a well setup U.S. Divers Mistral is a real pleasure to use with lower pressure cylinders. I'd put it near the top of my list.

[Mudhog]

Well, long as I'm messin with Mistrals, (see I can spell it right) I took apart #2 or as I will always think of it as Old Stinky. Somebody dunked or sprayed this poor thing with something that is suppose to smell good or cover up bad smells, but to my nose is just vile. Left outside it has purged most of the maloder thankfully. Just got the top can off and found the duckbill laying on top of the diaphram, no sign it was ever installed on the exhaust horn. Spose that was an LDS trick to convince divers to "upgrade" their equipment?
Anywho, enough corosion to warrent a rebuild kit.