USD diaghram identification

[Michel]

Since we're on the identification train,
Does anyone know the difference between the bronze colored inner
plate of the diaghram and the ones that were shiny (silver) plated on the USD AM? I think Chucko may have mentioned a while back that the bronze colored ones were military????? Any info....anyone.
Cheers,
Michel A.

[duckbill]

Pretty sure the colored ones were the military ones, and the rubber is said to be thicker in them too, though my military diaphragm and civilian diaphragms all measure about the same through the rubber web.
It's interesting, too- I just measured the metal plates, and the military one is thinner than ther civilian ones. Military .020", civilians .025. I only have one military diaphragm, so it's hardly conclusive.

[Broxton Carol]

I have not seen seen a bronze colored diaphragm in a usd reg, those are the ones that were in the VOIT products. They didnt hold up well. The USD had 2 different rubber diaphragms, the early one which was similar in posture to the fabric ones in the very early broxtons, and the later one with the higher crown, that more conflrmed to the finger position of the levers on the aquamaster and royal. The early fabric diaphragm sat way low, right even with the lever, and had a big brass plate rivited in to secure the fabric. The BLACK diaphragms were what I call the low profile ones, and these set the tabs on the diaphragm right on the lever in these early BROXTONS, and the DA NAVY! These were BLACK on the metal part with the tabs. The later Aquamaster types were of stainless steel, and looked shiney. The rubber part on these sat up a little higher, and was more conformed to the aquamaster lever. You can use a late type in a broxton, it works fine, but breathing on land will be bad, as so much of your breath will be needed to displace all that air, and cause a vacuum to facilitate air flow! In the water, the pressure immediatly puts your diaphragm into position on the fingers, or horseshoe, and the reg is right in sinc then. Dont worry about having a real like new diaphragm. The water is a powerful force in its operation and its not just you breathing in to create a lower pressure than the ambient water pressure, its the water pressure on the outside of the regulator thats doing the hard work, operating your regulator. GENIUS!! Hope this helps you Michel.

[nemrod]

I have some with the brass insert, they seem to have a thicker skirt and lower profile and the outer rim does not have the indentation for the can. I have some with a "shiny" silver insert and they seem to have a taller profile and thinner skirt and breath noticeably better than the brass colored versions and have an indentation in the rim for the cans. I have another that has a black metal insert and it is very thin and flexible.

None of them compare favorably to the performance of the new silicone diaphrams other than the outer rims of older indented diaphrams seem to lay in the can better. Well, actually, the brass colored diaphrams I have have a rim shape the same as the new silicone diaphrams--a little thicker but they clamp down nicely with the band clamps and do not leak and breath very nice and easy.

My NOS RAM has a silver diaphram, clear cage valves and apparently it has factorey silicone cage valves. This was a new regulator, it is a late round label with heavy yoke.

I wonder if some of the variations were just that the vendor sourcing changed over the two decades of production more than an actual change of specification by USD/Voit?

Nemrod

[Michel]

Chuck,
I'm not sure you're right on the bronze being a Voit destined product. I remember reading somewhere on VDH site that the
bronze ones were military and stiffer for response and durability,
although I think it would be fairly hard to measure. As the Brits would say maybe we're just making 'a tempest in a teapot'? A little like saying a Green label trademark is better than a pale Blue label trademark?! What do say Chucko?(I think I already know the answer).
All the best ,
Michel A.

[Broxton Carol]

Michel, I thought you meant the color of the diaphragm. Thats what I was talking about. The old flat diaphragms, most all have the black paint on the metal piece. They are bronze color underneith the paint! They are for the old da navies, navy type DA, and broxtons as replacement. These are the bronze color metal under the black coating..... The ones that are new that Ive seen have no indentation for the cans in the rubber, but if you clamp them in there, they will soon get them! As to which broxton is better, they all breathe about the same. A popular improvement is to install a pair of hoses with the inhale exhale valves. This makes them breathe better, as your not displacing ALL that area in BOTH hoses at the same time, just the inhale side.........to lower the internal pressure of the can, and let the water do its work.There are two factors to remember..... beauty is in the eye of the beholder, and the other factor is pride of possession. I have several broxtons, and while they are no big deal, I Like them, as they were from the same era I was young and would have given anything to have one back then. Now I am the kid again..!!! ;D

[Michel]

Chuck,
I understand perfectly! The older stuff is like a mini time machine for
me too and 'perdition to our enemies!', it works does'nt it?
Michel A.

[duckbill]

In my post, I was referring to the color of the metal disc of my DAAM diaphragms, not the rubber itself. All the rubber on my DAAM diaphragms is black. Some are older and stiffer, but they all measure about the same (hard to measure soft materials).

BTW, here's a quick tip-
If you have a Mistral whose seat vibrates and chatters (makes a honking sound during use), try a stiffer diaphragm.

[SeaRat]

Michel,

Actually, there were some rather different diaphragms from USD for the Jet Air regulator. It had a plastic insert in the diaphragm that was thicker and very slick. But it lacked the raised sections, as the Jet Air regulator did not use the horseshoe demand valve, but instead used the Mistral double lever system.

John