Change to diaphragms

[Bryan]

I am anxious to hear what Jim thinks of the Argonaut after a 100' ice dive

I'll be reading about it wearing shorts and sandals though

[EHowe]

Using an original diaphragm with an HPR is like putting snow tires on a super car...

When I say "Old Style" I meen the VDH replacement & maybe what I'm drinking when playing with my regulators in the garage

[Nemrod]

I have my Navy PRAM/HPR set to approximately .6 inches as measured on a Magnahelic, upstream of the intake cage valve. This is with the grey colored single stage diaphragm which I think is a Gen II version. Simply remove the grey diaphragm and install the superflex diaphragm and now the cracking effort is right at .3 inches.

I know I could dive this reg as is because my round label PRAM/HPR does exactly the same thing, Gen II to the new Gen III diaphragm and it has dozens of dives on it and some of them (shhhh, do not tell M.C.) exceeded 130 feet. It also was my regulator in Cozumel, max depthI think for this trip was only 100 feet (shhhhhhh, maybe a little bit more) and it was fine. Yes, it will try to free flow on the surface if I do not plug the mouthpiece or put my thumb on it and yes if I do a swimming roll, it will pressurize a little bit but nothing unusual. I think I like this sub .5 inch capability. I suppose one could install the shim for the HPR spring to get the cracking effort back up to a woeful .6 inches or just use a Gen II diaphragm instead of the Gen III (?) superflex type.

Really, it bears repeating if it is a repeat, subjectively, these regulators do truly perform on par with modern high performance single hose regulators. No, we will never eliminate some double hose idiosyncrasies such as the need to pay attention to tank placement or free flow tendency upside down etc. but but some of those things are what we love about them, the things I never particularly loved or found acceptable was the high work of breathing and that now is simply no longer an issue.

James

[Bryan]

These regulators do truly perform on par with modern high performance single hose regulators. No, we will never eliminate some double hose idiosyncrasies such as the need to pay attention to tank placement or free flow tendency upside down etc. but but some of those things are what we love about them, the things I never particularly loved or found acceptable was the high work of breathing and that now is simply no longer an issue.

James

Right on the $$$$

If I could get EVERY new double hose diver to spend the extra time and perhaps a little extra coin to get their regulator properly placed on their back from day one it would save dozens of E-mails that start out like.....The regulator you serviced for me breathes very hard....or I thought the Phoenix was supposed to make my DA breathe like my Atomic
Despite repeated attempts I have failed at getting double hose 101 clear enough for everyone....

[luis]

I always find it interesting how some divers try a double hose and immediately love it and others complain about how it breathes. I have not found an exact pattern, but obviously poor tank position is an immediate handicap.

Experience divers (especially those with any re-breather experience) tend to do better with a DH, but not always. I have also found some beginners that immediately love it.

In Cozumel we had two divers new to DH regulators that immediately loved it. Both of them are very experience divers, but one has never tried a DH before and the other had just very limited experience.

The first was Geiser, one of the dive masters. He used it with his normal jacket BC. He just lowered his tank and it worked perfect for him. Yes a DH can work with many jacket BCs if you can adjust it properly.

When he came out he said that it was one of the best regulators he has ever tried, he loved it. Keep in mind that he probably does well over 500 dives a year.

Here is a picture of him.



The second diver was Couv. He is also a great diver. He was using a Phoenix HPR with his Freedom plate. He tinkered with it for a few dives, but he was very happy from the very first dive. For a moment I thought that I was going to have a hard time getting my regulator back.

He was so impressed by the Phoenix HPR that he said (several times) that it breathed better than any single hose he ever tried (including his Scubapro Pilot)… I think the warm water and warm fresh air in Cozumel had him a bit narced


Here is a picture of Couv on the right.




Tank/ regulator position is probably the number one factor for a good breathing DH regulator to become an excellent breathing regulator in the water.

But, it also helps if it is an experience diver, with an open mind, and is willing to make adjustments to his kit, his diving position, and his breathing if needed. Having a bit of knowledge about the very basic diving physics also helps… It is all about the pressure in the water column.

The two divers mentioned above have all of those characteristics.

Edit: forgot to mention, pictures by Nemrod.

[Drado]

Something I've been meaning to ask for a time: Did the diaphragm get either thinner along the edges or softer? I noticed that I had to tighten down my band clamp a bit more than when using the previous silicone diaphragms, and even then - with a little force on the horns - I can still rotate the cans a bit. I'm getting 2.99mm on my old diaphragms and 2.6mm on the new ones around the edge measured with my micrometer.

[Bryan]

Slight change in thickness and durometer...Lots of folks re-chroming, powdercoating could not use the reproduction diaphragms since the finish on their cans was thicker. The LaSpirotechnique divers wanted one a bit thinner than the USD so it would make assembly of their regulators easier. Plus Luis and I were looking forward and planning for the future.
One mold is used to make the single and two stage diaphragms so I did my best to make everyone happy.

[Creed]

I noticed that I had to tighten down my band clamp a bit more than when using the previous silicone diaphragms, and even then - with a little force on the horns - I can still rotate the cans a bit.

My PRAM also allows a small bit of rotation in the cans, even tightened up pretty good. I've thought about making a thin nylon gasket to fit the outside lip of the diaphragm to allow a bit more compression, but it occurs to me that this would likely introduce a new area of slippage.

[Nemrod]

People hav occasionally had slippage with original diaphragms. The culprit can be several things;

1. Using lubricant on the parts.
2. Band clamp is oversized due to spreading and over tightening or original tolerance.
3. Cans have slight variation in the height of the lip.
4. Cans are warped.
5. Band clamp is simply not drawn down enough.

Solutions:

1. Clean all parts with Dawn or similar.
2. Replace band clamp.
3. Compare suspect cans with another set, possible in some cases (one I came across) that the band clamp just does not work.
4. Straighten or replace cans
5. Tighten clamp fully

It is also possible, maybe, to squeeze the band clamp at three locations evenly spaced to restore clamp grip.

James