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Post by nikeajax on Jan 3, 2019 18:03:47 GMT -8
Good for you buddy--REALLY! Before starting work on any reg, you should have at least a basic knowledge as to what kind of valve you're working with and the principals behind said valve's operation. I know that Phil knows what he's doing, but as a personal friend of his, I know I can give him some friendly ribbing: that's just our sense of humor JB
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Post by SeaRat on Jan 3, 2019 18:27:49 GMT -8
I want to reiterate that the Snark III can be relatively easily converted to utilize LP peripherals, but YOU MUST HAVE A MEANS OF MITIGATING runaway IP WHEN it happens. And, it is likely to happen! The Snark has an overpressure relief valve in it because it has a tilt valve 2nd stage. This is an upstream valve that gets closed tighter with higher pressure, rather than looser like a downstream 2nd. If/WHEN the high pressure side fails, the OPRV allows the excess pressure to vent, rather than blow up a hose or some other part. If you convert your Snark III for LP peripherals and eliminate the OPRV, you MUST add a DOWNSTREAM 2nd stage. I can see someone wanting to maintain the Snark heritage and installing a Snark II, Ibiza, etc., tilt valve 2nd stage into an adapter fitted into the OPRV port. NOOOO! I don't know what happens to the Snark internals if the IP becomes over-pressured to, say 3000 psig. Maybe nothing will explode, but you aren't getting the reg off the cylinder, unless you can bleed pressure off the reg. Doing so can't be safe, at least with anything I can think of. OK? Please let me know if anything I've stated here is not accurate. I think this mod is a good one, but I don't want anyone hurt! That's why the LP plug adapter is better, because the OPRV stays in place. If you put a downstream second stage octopus onto one of those LP ports, you automatically have an Overpressure relief valve too John
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Post by vance on Jan 3, 2019 18:57:26 GMT -8
I want to reiterate that the Snark III can be relatively easily converted to utilize LP peripherals, but YOU MUST HAVE A MEANS OF MITIGATING runaway IP WHEN it happens. And, it is likely to happen! The Snark has an overpressure relief valve in it because it has a tilt valve 2nd stage. This is an upstream valve that gets closed tighter with higher pressure, rather than looser like a downstream 2nd. If/WHEN the high pressure side fails, the OPRV allows the excess pressure to vent, rather than blow up a hose or some other part. If you convert your Snark III for LP peripherals and eliminate the OPRV, you MUST add a DOWNSTREAM 2nd stage. I can see someone wanting to maintain the Snark heritage and installing a Snark II, Ibiza, etc., tilt valve 2nd stage into an adapter fitted into the OPRV port. NOOOO! I don't know what happens to the Snark internals if the IP becomes over-pressured to, say 3000 psig. Maybe nothing will explode, but you aren't getting the reg off the cylinder, unless you can bleed pressure off the reg. Doing so can't be safe, at least with anything I can think of. OK? Please let me know if anything I've stated here is not accurate. I think this mod is a good one, but I don't want anyone hurt! That's why the LP plug adapter is better, because the OPRV stays in place. If you put a downstream second stage octopus onto one of those LP ports, you automatically have an Overpressure relief valve too John Thanks for underscoring that, John!
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Post by vance on Jan 3, 2019 19:01:17 GMT -8
I can see how some folks would want to add only a BC inflator hose to the Snark, w/o a safe second. Again, if you do this, you must retain the OPRV or add a downstream octopus/safe 2nd!!
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Post by herman on Jan 4, 2019 3:23:43 GMT -8
If/when IP runs away either a LP hose is going to explode or the HP diaphragm is going to rip. In either case, it's a bad day to be underwater with the reg.
A few more thoughts on the adapter. I think the port cover adapter is the way to go. Maybe making a 2 piece unit with a center bolt and radial ports around it. A circle or hex with a half moon shaped notch cut in it might look cool and give you multiple ports. The OEM OPV on those regs is a problematic and needs rebuilding. Why not leave the adapter in the OPV port and install a modern in it. They are adjustable and easy to find. Cheap at $6 or so. Or just make a plug for the OPV port and add a modern OPV to the adapter you have made.
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Post by surflung on Jan 4, 2019 6:44:23 GMT -8
Over Pressure Relief Valves - Vance/Phil, remember on another thread where I was showing my home made IP pressure gauge that doesn't have a relief valve? It has a bleed valve that starts in the open position when I turn on the pressure and is closed slowly with extreme attention to the progress of the needle on the gauge... So I can quickly open the bleeder valve if it's over pressuring. In this case I'm the human OPRV. - Well then, you showed off your much smarter IP gauge that incorporated its own OPRV. That got me to thinking and I did some searches to find a generic OPRV that I could just screw into my goofy IP gauge contraption. I actually found several but never got around to pursuing it further. I think I found less expensive IP gauges that already had the OPRV system integrated. - My Point? It's that OPRVs are not unique to the Snark IIIs. They're not a mystery and in fact they're completely logical and they're even part of the diagnostic process when solving problems. I have OPRVs on my RIX compressor and one day the second stage OPRV started burping. I asked my buddy Antique diver what to make of it and he said "There's nothing wrong with your 2nd stage... It's your 3rd stage leaking back into the second stage." I confirmed the leak with a gauge and ended up rebuilding/servicing the 3rd stage piston head... Basically cleaning the reed valves and replacing a few pennies worth of O-Rings. The fix was confirmed successful first with a gauge and then when the OPRV no longer "burped".
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Post by Deleted on Jan 4, 2019 9:59:35 GMT -8
Regarding the OPRV.......Yep, years ago I've been known to run thru three or four IP gauges before I got smart and opened the relief valve prior to turning on the air. I get my valves from Tractor Supply for about $16.....0-180psi........bending several in a row gets very expensive.
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Post by vance on Jan 4, 2019 10:02:43 GMT -8
Herman,
Good point on replacing the valve. I ruined the little rubber gasket taking it out. It was pretty crumbly. An o-ring might work as a replacement, but why not get a new and reliable one?
I won't use one on my setup, though. I have some period correct downstream 2nd stages, including a Nemrod Delta. I'll probably use a better breather than that one since this is supposed to be a diver.
At this point, I'm going for the simple adapter with a 3-way. The radial, multi-port adapter you describe would probably be better left to a proper machinist!
Eben, That's true! There's nothing mysterious about them. They're a safety feature. Many single hose regs have OPRVs. They are mostly tilt valves, but I've even seen them on regs with downstream 2nd stages (this may be the result of parts switching).
The Sportsways HydroTwin and DualAir DH regs have them, too, since they use a tilt valve second stage. My HydroTwin II has a downstream 2nd stage, and doesn't have a relief valve.
The OPRV can be used to set your IP w/o a gauge, as well. John outlines a procedure for ball-park setting the Dacor double hosers w/o using an IP gauge, either on this thread or the one he referenced on page 1 of this thread.
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Post by vance on Jan 8, 2019 14:28:39 GMT -8
Here's my newest LP adapter. I think it's a good one! I got brass in pocket! Here's the 250ft Snark wearing its new port!
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Post by nikeajax on Jan 8, 2019 16:33:24 GMT -8
Heeeeeyyy, that piece... looks... mighty familiar...
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Post by vance on Jan 8, 2019 17:48:23 GMT -8
Yup, that's the swivel you sent me! It isn't the right thing for this application, but it shows the function of the LP port! The swivel goes back on my HTII when I'm done reworking it.
But, don't you recognize that Snark Super?
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Post by nikeajax on Jan 9, 2019 9:00:26 GMT -8
Oh, that one also? Glad you're usin' that too JB
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Post by vance on Jan 10, 2019 10:37:44 GMT -8
Oh, yeah! I've got 4 Snark IIIs. I've got the Super, the 250ft Snark, a black label Silver, and the newer style Silver. Have I mentioned that I like Snark double hosers?
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Post by nikeajax on Jan 10, 2019 13:11:44 GMT -8
Phil, could you give us a brief synopsis as to the differences in each model: please? JB Here are some of my images of the Super:
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Post by vance on Jan 10, 2019 19:32:10 GMT -8
The Super is...,.... well, Super! It's a nice shiny chrome model, as opposed to the satin Snark III blue label, which is what the 250ft Snark happens to be. There are earlier models, the V-1 and V-2, which look a lot like the satin blue label. The Snark III also came in shiny chrome. Here's some pics of my regs. I've had a few: Label side of the Super Valve side of the Super Label side of the early Silver Valve side of the early Silver Label side of the later Silver Valve side of the later Silver Label side of the satin III
Valve side of the Satin III Label side of the shiny chrome III Valve side of the shiny chrome III I like all the Snark IIIs, but the black label Silver is my favorite, and the best one for my uses. It still has the retro label, engraved bottom can, AND has an HP port. Add an LP port plug and you can carry all the modern peripherals in a WAY kew vintage double hose regulator. I recently had a black label Silver which had the fancy peacock top casting, but NO HP port. Dunno. Maybe a built out of parts reg?
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