Vintage Double Hose

Amateur Diaphragm Project...
- I got the conshelf diaphragm but I don't have a hole punch and I didn't want to tear the new diaphragm by peeling the metal off the back. So, I've been procrastinating on this project... Finally yesterday I just jumped in with a different approach.

- The original diaphragm had a hole the size of a penny...

- I used the penny as a template to cut the hole. Then used drills to cut the openings. Caution, the drill can bite and nearly rip the diaphragm out of your hold.


Conclusions
- The drilled openings work fine but cutting the hole with a razor blade leaves rough edges and a possible poor seal. This diaphragm now works but whistles on exhaling... I think that's the rough edges. I also think it needs a larger one way valve with a little longer clearance on the center... This one is so tight it's kind of like an inside out umbrella.
- This is good enough to use for working on this reg further... It actually breathes pretty good but it occasionally has a pop or a snap of air that is unnerving... feels like its going to let loose and then stops... Then it breathes fine afterward.
- I think after I get the pop and snap figured out, I might do another diaphragm... This time with a punch hole.

That was a pretty clever idea of how to deal with the exhaust valve! The whistling will very likely not be an issue while diving. The water will dampen the exhaust valve's vibrations.

It is not uncommon for modern regs to have the same type of sound from the exhaust valve while at the surface.

Greg

Find a piece of thin wall pipe or tubing in the diameter you want the hole to be. Sandpaper the lip of the tube inside and out till its smooth. then you simply use it as a punch. If you use a dremel to sharpen or bevel the edge it works even better. I have seen guys heat the tubing before they punched out the hole but I don't think its necessary.

A scrap piece of electrical conduit and a bench grinder would make a great punch.

Jim

Neat idea to make the diaphragm. Cool to see another 40 Fathom ready to return to the deep..

Very resourceful!

- Thanks for the kind remarks and good advice... So its the old make-your-own-hole-punch-from-tubing-trick... I wish I would have thought of that! I may still be able to do that and clean-up the hole on this diaphragm... There's still plenty of surface area for a larger diameter exhaust valve.
- I won't worry about the whistle then. But that "pop" or "snap" of air sometimes happens on the first breath after turning on the pressure. It's like it's spitting for a second and then it stops and breathes normally. I'm thinking it's the low pressure seat. Is that something I can get parts for?
- Also, the original first stage has zero nostalgic value for me. That long, skinny piece of steel banged me in the back of the head eveytime my Dad let me try his tank and regulator. I'd like to replace that with something stubby and re-buildable. Can you guys suggest a first stage that will be compatible with this second stage?

Pretty much any first stage you like. If you want to stay small, I really like the old Healthways piston regs, they are tiny, parts are common and they work well.

Herman wrote:Pretty much any first stage

Conshelf....Been working for the last 47 years since it grew out of the Royal Aqua-Master....

What the Bumps Were For on the Old Diaphragm...
- I think I may have figured out what the four bumps were for on the original diaphragm. CLEARANCE... to ease the exhaling effort.
- I was test breathing this reg last night and it seemed kind of difficult to exhale. I'm wondering if the exhale pressure is pushing the diaphragm (and the exhale valve in the middle of it) against the front of the regulator... And holding the exhale valve closed? Bumps like the old diaphragm has would leave some clearance for the valve to open even with the diaphragm pressing against the front of the reg.
- The purge valve button may be protruding enough to blow this whole theory... I have to open it up again and look. But, it sure is difficult to exhale for some reason.

Good thought on the "bumps". Also keep in mind that the open area of your round holes is much less than the original cut out design, and the exhalation will be noticeably greater. The original wasn't too great on exhaling due to small size, and a quick estimate is that your openings may have half the surface area of the original.

Maybe you could take a Dremel to it and try to enlarge those openings. (I hope you have a steadier hand and more patience than I do!) Anyway, cool job on making your diaphragm.

BTW, it's not that hard to remove the old plate, carefully remove the plate from the new diaphragm with a good brand-new razor blade, and cement the old one into the new diaphragm. Cutting the plate off the new requires keeping the blade angled into the SS plate so that you are "shaving" the rubber off without damaging it. If you are inclined to try this, practice on the old one first... it's easy to nick the rubber.

Though I admit the nubbins might aid in that, if I were to hazard a guess, I think that a lot of the difficulty in exhaling can be seen in this photo first:


If you look at the amount of contact between the valve and the diaphragm, there's a lot of it that means more force to make it break away. I think minimizing the surface area of contact- sort of what was done with the umbrella valves and tapered spokes of the wagon wheels - would help.

(remember, this is just a guess though...)

Drado wrote:If you look at the amount of contact between the valve and the diaphragm, there's a lot of it that means more force to make it break away. I think minimizing the surface area of contact- sort of what was done with the umbrella valves and tapered spokes of the wagon wheels - would help.

(remember, this is just a guess though...)

- I think you're close to what's happening, Drado. That valve is so tight it's flexing inward. I breathed through the holes before I put the valve on and it wasn't bad at all. I've got a couple of the new wagon wheel valves and I think I'll try one here. I think I can get the right tightness with small washers on the the valve retainer flange.
- I also think I'll use a small file to open and square up the holes for more flow capability. The lever on the back is a horseshoe and I can't go much beyond the original diameter without the horseshoe ends overlapping the holes. But, there IS room for those holes to open up a bit.
- I took the first stage apart to see what could fix that spitting problem. Not much to it. If I could get a new seat from someone that would probably be good. Anybody out there have a new seat I could buy?

Yes, I know this is an old topic...but I just bought a Voit 40 Fathom Regulator online last night. It is my "entry level" Voit Regulator and I'm guessing that it will need to be worked on before diving. This topic might be of help...or I might have more questions to ask. Looking forward to getting my first Voit, even if it is not an iconic double hose Voit.
Mark

TomcatPC wrote:Yes, I know this is an old topic...but I just bought a Voit 40 Fathom Regulator online last night. It is my "entry level" Voit Regulator and I'm guessing that it will need to be worked on before diving. This topic might be of help...or I might have more questions to ask. Looking forward to getting my first Voit, even if it is not an iconic double hose Voit.
Mark

Show us a photo of the first stage, or email it to me. If it's what I think, I have rare New Old Stock high pressure seats for it!