Turning a BC pressure valve into a dump valve

[Marek K]

It takes a little bit of practice to find it, but after a few dives it's easy.

What's your reason for asking? And just who are you asking? I don't personally have a problem with dump valve doodads.

Well, I'm asking you, since you brought it up.

The reason I'm asking, since you asked (so this doesn't count as a hijack ), is that my wife has a very old (1985) SeaQuest stab jacket that she's going to be using now, after 14 years of not diving. All it has is the inflator hose to deflate it; the hose does have a pull dump. Beside that, there's a single overpressure valve at the bottom rear, but without a cord to make it a dump valve. And I'm thinking of converting it for her, so she doesn't have to go vertical to dump air.

I'm not at home right now, but I'm pretty sure I can easily attach a cord to the spring-loaded valve disk itself; it's recessed, so the knot wouldn't interfere with the rubber gasket. I'd just have to make a hole in the threaded cover; maybe melt it through, so it would end up with a reinforcing welt.

And add a "dump valve doodad" to the end of the cord.

These valve assemblies aren't standard; the threading is completely different than on my BC's dump valves... so just finding a new cover won't probably work.

Comments?

--Marek

 

[jagfish]

Sounds like you have an enviable excess of time on your hands...

 

[Marek K]

Sounds like you have an enviable excess of time on your hands...

You talkin' to me?

If so... it's not so much excess of time, as shortage of money... like for a new BC for her. And making a hole and tying on a cord won't take much time, either... assuming I won't screw anything up structurally to the valve -- particularly the cover.

 

[jonnythan]

Well, I'm asking you, since you brought it up.

The reason I'm asking, since you asked (so this doesn't count as a hijack ), is that my wife has a very old (1985) SeaQuest stab jacket that she's going to be using now, after 14 years of not diving. All it has is the inflator hose to deflate it; the hose does have a pull dump. Beside that, there's a single overpressure valve at the bottom rear, but without a cord to make it a dump valve. And I'm thinking of converting it for her, so she doesn't have to go vertical to dump air.

I'm not at home right now, but I'm pretty sure I can easily attach a cord to the spring-loaded valve disk itself; it's recessed, so the knot wouldn't interfere with the rubber gasket. I'd just have to make a hole in the threaded cover; maybe melt it through, so it would end up with a reinforcing welt.

And add a "dump valve doodad" to the end of the cord.

These valve assemblies aren't standard; the threading is completely different than on my BC's dump valves... so just finding a new cover won't probably work.

Comments?

--Marek

I'll split this off into a new thread if anyone but me responds to it, but it sounds like an OK idea to me. Not sure how you plan on getting the string to solidly attach to the disk, but go for it.

 

[Marek K]

I'll split this off into a new thread if anyone but me responds to it, but it sounds like an OK idea to me. Not sure how you plan on getting the string to solidly attach to the disk, but go for it.

Thanks for the potential split, Jonny.

If I remember right, unlike the threaded cover, the disk already has a cord-sized hole in the middle of it with a knot-sized recess on the interior side of the disk, so the gasket isn't affected. It's just the cover I'm worried about, if I make a hole in it... if the hole structurally weakens the cover, and it splits/breaks, then there's obviously nothing holding the valve together. Hence my thought of building up a lip or flange around the new hole by melting, to reinforce the hole.

Oh... and like walkinghispath, I'd need a doodad. (See how I tied this back in to this thread?)

 

[jonnythan]

Split done

 

[redacted]

While not a single standard dump valve, I think I have found 4 different sizes so far. If you do mess it up, you should be able to find a replacement. I think I'd just go ahead an drill it. It should not be a high stress point and hot nails somehow like to get stuck in plastic.