Really, how much creep is a problem.

[AquaNSun]

I will use the Mk2 for testing. I just need to take out 2 LP plugs (on opposite side) and I can see/inspect the seat immediately without dissembling the body. With the help of an IP gauge, this process should be painless. For those who is doing this experiment, I think a long term wear testing (with different hardness) is important. Actually, if we can test 2 seats (one original, one homemade) side by side under the same controlled environment, the results collected would be very useful. If the Mk2 material works, the balanced seats should be closed. We just need to get the first one right!

 

[AquaNSun]

Couv, I would like to make the first stage torture chamber like yours, would you show me the steps and parts?

Thank you.

 

[Couv]

Sure,

I went to Granger and bought a 175psi relief valve, then to the hydraulic shop to get the reducers except the one that is screwed directly into the lp port, I had that one. It's the type that allows you to use a modern SPG with an older regulator. (7/16 to 3/8 adapter)

Ref the picture, it's: pressure relief valve-union-reducer-reducer.

The only modification I did to the relief valve was to put a key chain ring on it to make it easier to pull.

If I were to do it over again, I would start with a smaller diameter relief valve to eliminate some of the adapters and reducers.

Couv

 

[Paladin]

Shees, I just realized I was neglecting my own thread, sorry about that.

First off Couv, I started with know working regs, carefully removed the HP seats and installed my homebrew ones in their place. Since my last post I have added a US Divers Aquarius to the mix. It is a basic flow by piston like the MK-2. After a few cycles it seems to have locked up solid and the MK-5 is also locking up fairly good now. The seat material may be just a little harder than factory and needs a little longer to take a set. There is another USD Aqu being tested by another SB member with homebrew seats and from what I have heard, his are doing well also.

I will try and work up some details for you guys tonight and post something later this evening.

I am that "other SB member" Herman mentioned. The Aquarius I am testing stabilized at about 137 psi with no further creep after sitting on a tank at 3000 psi for over a week. I took it out yesterday and dived it to 24 ft in the Ohio river. It worked flawlessly.

The factory IP for the Aquarius is supposed to be 128 psi to 132 psi. I prefer mine to be between 135 and 140, as this seems to make the reg breathe a bit easier as the tank pressure drops.

Even if it should turn out that the material is a bit soft and the seats wear faster than normal, they are ridiculously cheap and easy to make and replace.

Thanks, Herman!

 

[AquaNSun]

Paladin954,

Are you also using the same material as Herman - the Extruded Plastic NATURAL Round Teflon Virgin, hardness 50?

I got one similar material from McMaster and it costs $0.90/ft which you can make about 40 seats!

 

[Paladin]

Paladin954,

Are you also using the same material as Herman - the Extruded Plastic NATURAL Round Teflon Virgin, hardness 50?

I got one similar material from McMaster and it costs $0.90/ft which you can make about 40 seats!

Yeah. Herman sent me a sample of his material to play with and, so far, it works just fine.

 

[AquaNSun]

This is my preliminary testing results of a homemade HP seat for Mk2. My setup was Mk2 + IP gauge + SPG + 2nd stage. Testing period was 52 hours and manually purging my 2nd stage 100 times each for a total of 1000 times. Purging were performed at different intervals over the entire 52 hours. Since my tank was low I was only able to test at lower range. Also, I didn't have the cutting block yet so I just manually trim off the sliver as flat as I could.

Results:

Tank pressure: 750psi - 500psi.
IP reading: 125psi - 122.5psi stable with creeping no more than 3psi.
IP dropped per breath: 15psi and 10psi stable at the end.

Observations:

1. When I turned on the air for the very first time with homemade seat, IP was locked at 127psi at 750psi tank pressure. Everything was normal.

2. The grove pattern seemed to be different from the original seat as shown in picture. I think once it's cut-in and become stable, the uneven surface of homemade seat seemed ok.

3. After 52 hrs (actually sooner), IP locking was good but not solidly as it crept slowly a bit but no more than 3psi and then stayed solidly.

Any thoughts/inputs are welcome and thanks Herman for helping me to make this experiment possible. Testing at 3000psi will be done later when I get my tank filled.

 

[Md Spear]

Dude....you gota get out more!!!!!

all kidding aside , well done my friend.

 

[AquaNSun]

Question for the experts and scuba technicians:

Looking at the grove pattern, do you think the wear is normal or too soon if there is an indication at all?

 

[halocline]

Hard to say anything about the wear pattern, but if the original seat is slightly conical (it's hard to see, but the MK2 seats I've seen look flat to me) then the flow might be a little better than on the home made one. I doubt it would ever be noticable, but theoretically the conical seat will allow more flow.