Service kit for this Beuchat Regulator 1st and 2nd stage

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gumbumgum

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Tony Pr

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Thanks @gumbumgum and @SubseaSports for the responses. Very useful. Especially the instructions and IP at tank pressure of 200 bar.

@SubseaSports I am not planning on modifying the spring. It is clear that the seat needs to be replaced in the 1st stage, I was just wondering hypothetically how to decrease the IP with just that spring and no other adjustments. I am sure a new seat will decrease the IP and get rid of the free flowing second stage issues, given the age between services.
 

rsingler

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Yes, changing the seat will present the volcano with a surface that's no longer indented, and therefore fractionally closer to the knife edge. That means the mainspring won't be compressed as much and will seal sooner at lower IP.

But for the record, if you have a spring from which you just can't get a low enough IP, you can indeed shorten it. Using a belt sander, and careful placement of the top or bottom flat against the belt with low belt speed and frequent water cooling to prevent changing the temper, you can take off 10/1000th's of an inch and lower your IP 5-8 psi, with about 3 minutes work. It's a strictly unauthorized repair, but done carefully, it's an easy, safe solution to the problem, especially if getting a new mainspring is no longer possible.
 
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Tony Pr

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Thanks @rsingler ! I like your idea and if having trouble in the future will use it. I have not yet ordered a service kit (I should though). To give you a bit more of an update, there was IP creep in the regulator until the second stage started freeflowing (need a new seat). I took the old seat out and sanded the round indent that was on it (from the volcano) down to flat. used some rough paper to start with then got finer. Cleaned it all up, re-installed.

No more IP creep now. When on a full tank the IP is 130 PSI then slowly drifts (over about 60 seconds) to 175 before locking up. I assume this drift will go down as the regulator "reseats". No freeflow on the regs now. I am yet to take for a test dive, but will do in the coming weeks. This seems fine to me. I believe by shortening the seat this will increase the IP (needing more pressure against the spring to close the valve).

This is a temporary thing until I get a service kit.

I don't think my seat sand down is an authorized repair either haha.
 

rsingler

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You can punch a disc of the right diameter out of sheet plastic, and shim behind the HP seat you sanded. You might need a thinner sealing oring on top of it to allow it to move closer to the piston, but that'll reduce your max IP.
 
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Tony Pr

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You can punch a disc of the right diameter out of sheet plastic, and shim behind the HP seat you sanded. You might need a thinner sealing oring on top of it to allow it to move closer to the piston, but that'll reduce your max IP.
That makes a whole lot of sense.

Purely out of interest, I assume these techniques are able to be applied to most piston regulators?
 

rsingler

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That makes a whole lot of sense.

Purely out of interest, I assume these techniques are able to be applied to most piston regulators?
Yes, as long as you understand that they're strictly unauthorized modifications from the mfr's point of view.

But yeah! They all make sense...
Increase the distance from piston knife edge to seat and it requires more spring compression (higher IP) to seal.
Increases are from knife edge restoration (that shortens the piston microscopically), and seat reflattening as was described here.
Decreases in distance (which allow sealing before much main spring compression, with lower IP) are by using a taller seat, or shimming it as I described.
And of course, direct increases in spring tension by spring shims (which ARE authorized) will also increase IP.
 

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