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Post by vance on Sept 25, 2019 15:47:57 GMT -8
I have a couple ideas about converting a Healthways ScubaStar type first stage to a doublehose. Any thoughts?
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Post by SeaRat on Sept 25, 2019 18:28:59 GMT -8
It's an awfully small first stage to go with a conventional housing for a double hose second stage. How about a stand-alone second stage/double hose housing which could be fed by any first stage. As an added bonus, it could be chest-mounted.
John
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Post by herman on Sept 26, 2019 3:31:17 GMT -8
the only way I can see to do it would be to do something similar to what A L did with that mess they made in 2000, basically attach the first to the cans then install a second stage into the cans, supplying the second with air via a hose. IMO the only good way to do this is to use one of the few linier flow pistons regs ( I only know of a couple that were made), make a new end cap for it and somehow create a second stage to go with the end cap. I have toyed with this some and have a reg in mind but like so many things these days I have more ideas than time to spend on them. The new end cap is fairly easy but I have yet to figure out a second stage design to go with it.
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Post by vance on Sept 26, 2019 9:02:00 GMT -8
It's an awfully small first stage to go with a conventional housing for a double hose second stage. How about a stand-alone second stage/double hose housing which could be fed by any first stage. As an added bonus, it could be chest-mounted. John That's one way to go about it. It would be pretty easy to do. It is also pretty much the same concept I have in mind, but the first stage would be mounted to the can, and a short pipe and fitting for the second stage would be screwed into the LP port of the first.
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Post by vance on Sept 26, 2019 9:14:47 GMT -8
the only way I can see to do it would be to do something similar to what A L did with that mess they made in 2000, basically attach the first to the cans then install a second stage into the cans, supplying the second with air via a hose. IMO the only good way to do this is to use one of the few linier flow pistons regs ( I only know of a couple that were made), make a new end cap for it and somehow create a second stage to go with the end cap. I have toyed with this some and have a reg in mind but like so many things these days I have more ideas than time to spend on them. The new end cap is fairly easy but I have yet to figure out a second stage design to go with it. I'm thinking of cutting and threading the end of the piston cover of a Healthways Scuba Star type first stage for a large nut to attach the can. It will probably need a flange to provide a seat for a gasket. I'd prefer to have the holes inside the can rather than in the water, but these were made to be flooded, so it doesn't matter much. I suppose the cover could be machined on the inside end to become the attachment nut, and would accomplish my preference. I'll look into that. A short, curved brass tube with fittings on both ends would both supply and mount the second stage. It might be possible to use a modified singlehose second stage with an adjustable seat like I wanted to use in the Dacor conversion, since this is the same kind of setup as a single hose.
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Post by nikeajax on Sept 26, 2019 9:26:58 GMT -8
Phil, what if had it so that the bonnet/end cap is what secures the first stage to the cans? Are you going to use FX-cans?
JB
EDIT: I think Scubapro had a flow-through piston that would allow you to avoid all the screwy plumbing...
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Post by vance on Sept 26, 2019 10:21:39 GMT -8
Phil, what if had it so that the bonnet/end cap is what secures the first stage to the cans? Are you going to use FX-cans? JB EDIT: I think Scubapro had a flow-through piston that would allow you to avoid all the screwy plumbing... That's what I was talking about when I was ruminating about machining the bonnet (that's the word I was trying to remember!) on the inside end. That is probably the best way to go (if it'll work). I am thinking about using cans from GL or a Deluxe just to keep it all in the family. I have both that have no valves and aren't in great shape. If I make this DH, I'll probably get all the parts chromed. The tube supply line/second stage mount could be an advantage, since it can be placed right at the intake horn. Which model Scubapro first are you thinking of?
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Post by SeaRat on Sept 26, 2019 10:34:36 GMT -8
I would second Jaybird's idea of using a Scubapro flow-through piston first stage, as these are balanced first stages. The Scuba Star piston first stage is unbalanced, meaning that the interstage pressure will go down as cylinder pressure goes down--a regulator made with this first stage will breath harder toward the end of the dive.
John
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Post by nikeajax on Sept 26, 2019 11:02:21 GMT -8
Phil, sorry I really don't know, I just have a vague recollection of it: look on eBait?!?!?!?
JB
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Post by nikeajax on Sept 26, 2019 12:17:08 GMT -8
Hmmmm? I know for a while people were gutting the first gen 1665 Scubairs just to get the plunger out of them. See if you can find one of those instead maybe? But the 1664 Scuba Star is quite ubiquitous though... Again, just brain storming... JB
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Post by vance on Sept 26, 2019 17:19:42 GMT -8
That's what I was thinking. Don't care if it's balanced. I'd like to make a simple piston type first stage mod from SH to DH. Just for grins?
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Post by vance on Sept 26, 2019 17:23:17 GMT -8
I'm turning some more second stages for Dacor Oly conversions and Titan IIs. I think I have a simple second stage for the HW piston conversion based on them. The new part, the curved tube with an LP connector and a second stage fitting is the wild card. It should work, though.
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Post by nikeajax on Sept 27, 2019 14:55:18 GMT -8
No, it will work: I know you, you'll make the damned thing work even if it kills you But I doubt you'll need to go to that length... JB
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Post by vance on Sept 28, 2019 8:00:56 GMT -8
I'm eyeing a Conshelf VI first stage for this mod as well. I don't know which one will win out, but the Conshelf has a couple of advantages. Being balanced is part of it, but the body looks like it would be easier to mod for attachment to the can. It would still need the tube.
I'd narrow the hex on the HP seat retainer to gain a little more length for a threaded section to slip inside the can and hold with a large nut. That would also provide a flange for a gasket.
The HW bonnet would need to be cut similarly, since having the bonnet protrude into the can would be awkward and might interfere with the diaphragm. Also, a flange would have to be made or added somehow.
Dunno. We'll see.
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Post by vance on Sept 28, 2019 17:04:08 GMT -8
I made a couple of upgraded Delrin second stage bodies for my Titan II conversions today. They came out really good, BTW. While at it, I was thinking about how to go about the double hose/single hose conversion I've been geeking out about lately. This is not so hard, I'm thinking.
While you all might be feeling that an external tube from first stage LP port to second stage mount might be all kludgy and awkward, I don't think so. I think it could be done tastefully, ala the tube on the MR 12 III second stage. We'll see.
That kind of setup would work with a lot of single hose first stages as long as you can come up with a way to mount the can.
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