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Post by Aquala1 on Jan 16, 2023 10:48:06 GMT -8
I have an exploded view of the GL in pdf if you want it - think you still have my email. For some reason, I think the oring is a 907, not sure but easy enough to measure. In any case, it should be a 90 durometer since it is across high pressure (basically 3k to atmosphere with a full tank). As a general rule, the more pressure differential across an oring, the harder (larger durometer number) it should be. Although different materials and durometers are used, burna-n in 70 and 90 are common in scuba equipment. I most likely have a big bag of them if you don't want to buy a bunch Herman, not to hijack and sidetrack this thread but I’m in the process of rebuilding a Voit manifold from the late’60s. One of the parts specs lists one of the o-rings as a “906”, but nothing in any of the dive parts catalogs (like Triton) show a 906. I even called a local rubber and gasket supplier and they said that anything in the 900 range would be huge. You mentioned a “907”, so do you know what a 906 is?
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Post by herman on Jan 16, 2023 18:56:53 GMT -8
Be very cautious if they don't know what a 900 series is... The 900 series is one specially for straight hose fitting. McMaster Carr has them, you might try a hydrolic hose shop since they are for that type of fitting. 906 0.078 thick 0.468 ID 0.624 OD, it is used with 3/8 straight thread tube fittings. www.mcmaster.com/o-rings/dash-number~906/
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Post by Aquala1 on Jan 16, 2023 21:59:43 GMT -8
Be very cautious if they don't know what a 900 series is... The 900 series is one specially for straight hose fitting. McMaster Carr has them, you might try a hydrolic hose shop since they are for that type of fitting. 906 0.078 thick 0.468 ID 0.624 OD, it is used with 3/8 straight thread tube fittings. www.mcmaster.com/o-rings/dash-number~906/ Thanks Herman, that’s exactly what I needed to know.
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Post by vance on Jan 17, 2023 9:10:12 GMT -8
As noted elsewhere (probably many times), the tiny o'ring that seals the pin on a Mistral is a PITA to get out and to install a new one. It is responsible for a lot of bad language.
The GL does not use an o'ring to seal the pin. I'm not sure anyone has tried it, but the Mistral would probably work fine without it. Of course, one should change it during a rebuild but it isn't strictly necessary, say if you were doing repairs on the boat/beach.
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Post by SeaRat on Jan 17, 2023 9:15:18 GMT -8
As noted elsewhere (probably many times), the tiny o'ring that seals the pin on a Mistral is a PITA to get out and to install a new one. It is responsible for a lot of bad language. The GL does not use an o'ring to seal the pin. I'm not sure anyone has tried it, but the Mistral would probably work fine without it. Of course, one should change it during a rebuild but it isn't strictly necessary, say if you were doing repairs on the boat/beach. I have worked on several Mistrals, plus a Stream Air and my Overpressure Breathing regululator, and have never replaced this O-ring. My understanding is that it is simply there to decrease/eliminate air from going around the pin and not out the nozzle. But a slight leak there will not really affect the regulator's performance. The old O-ring around the pin seems to still be doing its job after all these years. John
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Post by artc on Jan 17, 2023 10:30:08 GMT -8
As noted elsewhere (probably many times), the tiny o'ring that seals the pin on a Mistral is a PITA to get out and to install a new one. It is responsible for a lot of bad language. The GL does not use an o'ring to seal the pin. I'm not sure anyone has tried it, but the Mistral would probably work fine without it. Of course, one should change it during a rebuild but it isn't strictly necessary, say if you were doing repairs on the boat/beach. I have worked on several Mistrals, plus a Stream Air and my Overpressure Breathing regululator, and have never replaced this O-ring. My understanding is that it is simply there to decrease/eliminate air from going around the pin and not out the nozzle. But a slight leak there will not really affect the regulator's performance. The old O-ring around the pin seems to still be doing its job after all these years. John I’ve changed the o-rings (006) on all my Mistrals and Air Stream. I learned by following Bryan Pennington’s wonderful You Tube video on how to do it and have not had any problems. The key to easy removal is to get a new brass pick behind the o-ring and then twist the pick around and up. Works every time. To install the o-ring, I use a WD-40 straw and line it up per Bryan’s instructions. Then, I push the o-ring in using a wooden chop stick. Takes less than five minutes.
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Post by vance on Jan 17, 2023 11:46:43 GMT -8
It gets much easier with practice. I use a bamboo skewer to insert in the valve to guide the o'ring.
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Post by Tusker on Jan 17, 2023 14:16:12 GMT -8
These DW Mistrals are quicklly becoming my favorite DH regulator. They breathe great on LP tanks and are SO simple to repair and maintain. I found a nearly mint Warner with a long yoke on ebay and just finished rebuilding it. I will test dive it on Sunday. IMG_0266 by Arthur Challacombe, on Flickr I had my Gold Label open last night and looking back at this picture it's surprising to me just how similar the internals are — is this a general hallmark of single stage regulators? Jacob
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Post by SeaRat on Jan 17, 2023 17:14:04 GMT -8
Tusker, Most single stages are copies of the basic design that Gagnan invented for what ultimately became the Mistral. For U.S. Divers Company, there were three generations, the Overpressure Breathing, the Streamair, and the Mistral. The Overpressure Breathing was the best breathing of the three, but at that time divers did not like the "gush" of air it delivered; it used the hose-within-a hose to deliver the Venturi air directly to the metal mouthpiece. I have improved it be replacing the inner hose and the hose look with a much longer set of hoses, and am still blown away by its performance. The next is the Mistral, which has great characteristics, but is much noiser. La Spiro produced a number of variations of the Mistral, and also allowed companies in other countries to produce their own. _MG_5133 by John Ratliff, on Flickr The Healthways Scuba, Scuba Delux and Scuba Gold Label followed this same basic design. IMG_2683 by John Ratliff, on Flickr IMG_1423 by John Ratliff, on Flickr The exception is a rather rare regulator now, by AMF Voit, which developed a downstream single stage regulator that they called the VCR 50 Fathom, and marketed it from 1959 through 1961. It has an interesting, two-lever system that pulled the seat and disc assembly out, creating a very powerful Venturi. Voit then positioned the small hole toward the intake horn, and the large one (which had the major flow) into the case. This positioning vastly decreased the regulator's performance. When I had mine, I positioned the large hole down the intake hose, and WOW, what a difference. Had Voit done that, they would have blown their own two stage VCR Navy regulator, a knockoff of the USD Aquamaster, out of the water. John
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Post by nikeajax on Jan 17, 2023 17:29:26 GMT -8
The exception is a rather rare regulator now, by AMF Voit, which developed a downstream single stage regulator that they called the VCR 50 Fathom, and marketed it from 1959 through 1961. It has an interesting, two-lever system that pulled the seat and disc assembly out, creating a very powerful Venturi. Voit then positioned the small hole toward the intake horn, and the large one (which had the major flow) into the case. This positioning vastly decreased the regulator's performance. When I had mine, I positioned the large hole down the intake hose, and WOW, what a difference. Had Voit done that, they would have blown their own two stage VCR Navy regulator, a knockoff of the USD Aquamaster, out of the water. John Jacob, here's what John is talking about: I had waaaaaaaay too many regs, so I sold this one to Ty: BTW this one was never ion the Voit catalog, only the chrome version. Hope this helps? JB
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Post by Tusker on Jan 18, 2023 5:42:46 GMT -8
Thanks John and JB, that makes a lot of sense. Now it seems like I'll need a Mistral and an Overpressure to compare to the Gold Label once it's finished. . .
Jacob
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