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Discussion of diving methods and equipment available prior to the development of BCDs beyond the horse collar. This forum is dedicated to the pre-1970 diving.
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SurfLung
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First Name: Eben
Location: Alexandria, MN
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Re: Trieste Update

Mon Feb 08, 2021 12:55 pm

The Ultimate Solution...
- My original Trieste had one of the thin silicone duckbills in it and it was actually folded in half... Which may or may not have given some resistance to exhaling. I replaced this with the new molded silicone duckbill from The Scuba Museum.
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- Then, I finally noticed that the new silicone diaphragm is a little smaller in diameter so that the ridge on it's circumference doesn't grab the groove on the can. So I went back to the original handmade diaphragm and I could see the folded under part was correctable by trimming off excess silicone sealant. I was able to secure it full width and all the way around the circumference to the top can with Loctite Ultra Gel... It's a super glue that works with rubber. I had to do a little at a time but got the whole thing totally secured so it wasn't going anywhere.
Image
This is the original Bill Tucker ultra sensitive hand made diaphragm. You can see the new duckbill thru the diaphragm.

- With the diaphragm secure, it was easy to line up the top and bottom cans and fit the band clamp nice and tight.
- I put my thumb over the nozzle and sucked like heck on the inhale horn. It sucked down the diaphragm hard and held tightly without slipping, leaking, or sucking loose. Put the hoses on her and tried to hard suck it some more to see if I could get the diaphragm to suck loose or even leak. Nothing. We took it to the pool yesterday and dove it for about an hour. Works great. So my Trieste is restored to original cans and working great.

But the story doesn't end here... Phil has made me up a Titan conversion to put in my blue plastic cans. I'm looking forward to putting that together and I'll post the story here for those who might be interested :)
SurfLung
The Freedom and Simplicity of Vintage Equipment and
Vintage Diving Technique are Why I Got Back Into Diving.

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simonbeans
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Re: Trieste Update

Mon Feb 08, 2021 1:23 pm

Surf Lung:
But the story doesn't end here... Phil has made me up a Titan conversion to put in my blue plastic cans. I'm looking forward to putting that together and I'll post the story here for those who might be interested :)
I just posted a Titan II first stage for sale if anybody is interested doing what many have done.
Allan
Check out my website: www.vintagescubastuff.com

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SurfLung
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Re: Trieste Update

Fri Feb 12, 2021 3:16 pm

Looky What I got...
Image
- This is a Titan II single hose regulator which has been modified to include a double hose style 2nd stage. Vance did it for me. Now it works like a Trieste and I can install it in my blue plastic cans with double hoses!
SurfLung
The Freedom and Simplicity of Vintage Equipment and
Vintage Diving Technique are Why I Got Back Into Diving.

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antique diver
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First Name: Bill
Location: North-Central Texas

Re: Trieste Update

Fri Feb 12, 2021 9:34 pm

Very nice! :D
The older I get the better I was.

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rhwestfall
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First Name: Robert
Location: "La Grande Ile"

Re: Trieste Update

Sat Feb 13, 2021 12:35 pm

nice indeed
Bob

No Longer Awaiting my Kraken.....

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Vancetp
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First Name: Phillip
Location: Belmont CA

Re: Trieste Update

Sat Feb 13, 2021 8:15 pm

I am waiting on pins and needles for your dive report. It should be an excellent performer.

Please remember that the FX boxes can rotate on the first stage body under handling, which can degrade performance. The venturi jets are drilled precisely and need to point straight down the intake horn! You should make indexing marks on the first stage and the top box. Be sure to check them before entering the water!!

I am working on a way to key the 1st stage in the box. Not easy, b/c there's not much sealing surface.

BTW, you might think making the second stage body is difficult (and it isn't a piece of cake), but the double bend levers are a huge PITA to make. But, I'm getting into a rhythm.

My next project is a similar second stage for Dacor DH regs.

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antique diver
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Re: Trieste Update

Sat Feb 13, 2021 8:23 pm

Vancetp wrote:
Sat Feb 13, 2021 8:15 pm
I am waiting on pins and needles for your dive report. It should be an excellent performer.

Please remember that the FX boxes can rotate on the first stage body under handling, which can degrade performance. The venturi jets are drilled precisely and need to point straight down the intake horn! You should make indexing marks on the first stage and the top box. Be sure to check them before entering the water!!

I am working on a way to key the 1st stage in the box. Not easy, b/c there's not much sealing surface.
Maybe a pin going through the plastic from the inside, and into a shallow blind hole in the brass body. It would have to go in flush with the inside of the plastic can so the ring can screw on. Would the plastic be tough enough to handle that?
The older I get the better I was.

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Vancetp
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Re: Trieste Update

Sat Feb 13, 2021 8:28 pm

I think so. That could work. I don't think there's a lot of stress here. My concern is a seal.

My idea is to make a metal part like a washer with opposite sides cut down so it's a flat sided oval, then glued to the plastic box.

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antique diver
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Re: Trieste Update

Sat Feb 13, 2021 10:05 pm

Vancetp wrote:
Sat Feb 13, 2021 8:28 pm
I think so. That could work. I don't think there's a lot of stress here. My concern is a seal.

My idea is to make a metal part like a washer with opposite sides cut down so it's a flat sided oval, then glued to the plastic box.

Think about the Mistral. It uses a rubber gasket to seal around the registration pin, but you might be able to just use silicone sealant on the pin.
The older I get the better I was.

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ScubaLawyer
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First Name: Mark
Location: Laguna Beach, CA

Re: Trieste Update

Sun Feb 14, 2021 7:42 pm

As long as it is show and tell time: Here is my Tital II Fx conversion I put together last year. Breathes great!

Image
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"The diver who collects specimens of underwater life has fun and becomes a keen underwater observer. .. seek slow-moving or attached organisms such as corals, starfish, or shelled creatures." (Golden Guide to Scuba Diving, 1968) :D

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Vancetp
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First Name: Phillip
Location: Belmont CA

Re: Trieste Update

Sat Feb 20, 2021 8:44 pm

antique diver wrote:
Sat Feb 13, 2021 10:05 pm
Vancetp wrote:
Sat Feb 13, 2021 8:28 pm
I think so. That could work. I don't think there's a lot of stress here. My concern is a seal.

My idea is to make a metal part like a washer with opposite sides cut down so it's a flat sided oval, then glued to the plastic box.

Think about the Mistral. It uses a rubber gasket to seal around the registration pin, but you might be able to just use silicone sealant on the pin.
Yes, but the Mistral washer is more than 1/2" wide. The Titan II has a 1/4" -ish surface. Agreed, sealer will work, most likely, but it's hairy.

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luis
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Re: Trieste Update

Sat Feb 20, 2021 9:51 pm

When I was playing with the Voit Titan or Trieste (the Pegasus project :) ) in the plastic cans all I did was tighten the body ring with the gasket in place (fairly tight). I never had any issues with the can rotating.

Since the diameter of the two stage body (Trieste or Voit Titan) is much bigger that a single stage (Mistral), the amount of torsion required to overcome the resistance of friction is a lot higher. Torsion is directly proportional to the moment arm.

The friction from just clamping down on the gasket, times the moment arm, due to the diameter of the two stage body, seemed to be secured enough for me.

I tried twisting the can and I never could, but I didn’t actually measure how much force I could apply to the horn… I stopped applying force to the plastic horn when it felt like more than I was comfortable with. I have no numerical torque data.

YMMV
Luis

Buceador con escafandra autónoma clásica.

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Vancetp
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Re: Trieste Update

Sun Feb 21, 2021 2:49 pm

You must have applied a lot more torque to the ring than I! My boxes don't move super easily, but they do move during handling, sometimes.

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luis
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Re: Trieste Update

Sun Feb 21, 2021 11:17 pm

I applied a fair amount of torque. I applied enough torque so it would not move.

But just as important is to make sure the can and the regulator body are both clean. I use one of the new reproduction gaskets sold here (and make sure it is also clean). The coefficient of friction of rubber against either surface is very high, sometime rubber tends to even stick creating a coefficient of friction greater that one (we call it sticktion).
Luis

Buceador con escafandra autónoma clásica.

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SurfLung
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Location: Alexandria, MN
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Re: Trieste Update

Mon Feb 22, 2021 3:13 pm

How About the 50 Fathom Alignment Trick?

Neither of my Voit 50 Fathom VCR-2 regs will position the large venturi port to point directly down the inhale hose. So I have to mount it without the anchor pin and rotation is a possibility. I think Greg or Allan told me to use the snap ring on the nozzle sieve to mark the position of the venturi port. I kind of forgot about this and haven't checked it in awhile. But that's one way to reference the proper alignment.

BTW- Sorry so late on commenting. I was vacationing in Cozumel. Used my Kraken for some great nitrox diving. I'll give a report elsewhere.
SurfLung
The Freedom and Simplicity of Vintage Equipment and
Vintage Diving Technique are Why I Got Back Into Diving.

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