solution for D-series poppet seat DIY?

[GJC]

Might be a challenge to get a perfectly flat and level surface.

The brass on my seat looks like it has a depression for the rubber seat. How deep is it? I don't want to destroy mine to see.

Could an o ring or thin rubber washer fit in that depression?

 

[Open Ocean Diver]

That could work. Looking for Shore A55. Maybe look at the thread @Angelo Farina started about his DIY SPEC Boot for the compound he used. Critical to get a perfectly flat surface on the side opposite the disc (which is actually a hat with a central cylinder). A challenge indeed!

After taking one apart I see what you mean it’s not just a flat disk. Looks more like a hollow rivet.

 

[lexvil]

Uses the 104 D420 a little bit yesterday on a pony, the 104 is glued to the plastic holder with the tiny o ring on top, it performed well although it put out a lot of chatter when dry it was very smooth in the water. I’m going to buy one of those in-line shut off valves before using it as a primary again.

 

[Open Ocean Diver]

Was just thinking the seat looks like a small laminated plumbing seal I’ve seen before.

 

[Kupu]

Uses the 104 D420 a little bit yesterday on a pony, the 104 is glued to the plastic holder with the tiny o ring on top, it performed well although it put out a lot of chatter when dry it was very smooth in the water. I’m going to buy one of those in-line shut off valves before using it as a primary again.

I was not aware of the in-line shut of option, thanks for mentioning it. That would be nice to have (in addition to pony) when testing rebuilds on old oddball second stages and using dodgy DIY lp seat replacements.

I will make a hint to Mrs Claus that the DGX version looks like a nice stocking stuffer.

 

[lexvil]

I have my in line shut off so the new 104 bonded to the poppet shaft will get a few runs in tomorrow. This is not something I would normally use but it will go a long way toward testing confidence.

This thing works well but I’m wondering if I should also try the shorter one.

 

[lexvil]

2 1/2 hours underwater yesterday with the 104 slightly bonded to the poppet shaft, no issues very smooth and easy breathing, the in-line shutoff took the load off of my mind so that I’m comfortable with this after the blow out. I think I’ll order the shorter shut off and try that out to see how it would work with dry gloves.

 

[rsingler]

I tried to get Doug to put an inline shutoff on his set while he was trying them out in Key Largo. But he said the boat crew would laugh at him if he showed up to dive like that, and he demurred. Kids.

 

[lexvil]

I tried to get Doug to put one on his set while he was trying then out in Key Largo. But he said the boat crew would laugh at him if he showed up to dive like that, and he demurred. Kids.

Have him wear split fins, they will be completely distracted and miss the shut off.

 

[rsingler]

I can't let go of this poppet project of @Kupu's!
My 50 duro 104 poppets are still looking great after a month of sitting under spring pressure:

There's some impression from the knife edge, but she still cracks at 0.5". So far so good.
But unlike @lexvil, I haven't been able to dive it myself, and am still concerned about my son's reports of leaking until he increased cracking effort significantly.
As I experiment at home, my biggest concern is the intermittent leaking as I increase spring pressure. There isn't a consistent increase in cracking effort as I screw down the adjustment cap. Instead, I get intermittent leaks that I presume are due to spring "winding" and changing pressure. That could be a real frustration for the DIY guy who gets a leak and simply screwing in the cap doesn't reliably fix it. More particularly, I'm concerned that minute shifts in poppet position during a season of diving might yield a leak that won't go away with a simple "extra 1/4 turn".

To eliminate one variable (seat impression), I found a specific Viton that was billed as "super-resilient" and resistant to permanent deformation. Unfortunately, its lowest available duro is 75. But I'm experimenting with it now. In an effort to minimize shear forces between components, I ordered some 1x2.5's also in duro 75. But the added stiffness made for a clear shelf where the 1x2.5 stood proud of the shaft as I screwed down the top nut:

This was inconsistent at sealing, though the stiffer 104 meant that I could seal at 0.4"!!!
However, the poppet went from seal to leak to seal as I screwed down the cap, again suggesting a spring winding issue. So I added two graphite impregnated washers under the cap and on top of the poppet, to help spring slippage. No joy. Still alternately leaked and sealed as I screwed in the cap.
I was next thinking that the problem was the knife edge intermittently catching on the shelf of that 1x2.5 as it sealed (see pic). So my next experiment was removing the lower 1x2.5 and only keeping the upper (I know. I know. I was the one insisting on the importance of the lower o-ring). I'm trying to get around that with the silicone cement filler:

But these poppets are still curing, so I don't have an answer yet. More to follow!