Inexpensive LP & HP Quick Disconnects?

[SlugLife]

I would like to have quick-disconnects between the 1st stage & the LP hoses. I have several octos I'd like to setup this way, making it possible to remove or swap both the inflator hose & backup 2nd stage regulator. I'd like to do this to a number of octos, if I can get the cost per fitting down enough.

If I'm understanding correctly, I'd need a 3/8-24 threads to Quick-Disconnect on the 1st stage side, then Quick-Connect to 3/8-24 threads?

• What size of fittings should be used? (Does anyone have a good scuba-fittings guide?)
• Should I be careful to ensure the female side of the quick-disconnect is one way and auto-closes? Or are they usually that way by default? For example, if swapping a 2nd stage regulator underwater (not that I expect to do that in the near future).
• What's the difference between "locking" and "non locking"
• Direct links where you can pick up the correct fittings inexpensively or in bulks are also appreciated.

My regulators and hoses are Scubapro MK10, G250, and Apeks AT20 & ATX200, and standard BCDs if that matters, so fairly standard threading and fittings. I've also ditched all of the oddball 1/2 size hoses/items.

 

[Jim Lapenta]

You're liable to be introducing additional failure points needlessly. Why would you want a quick disconnect on the inflator? Hoses are cheap. If you need to swap a second stage underwater, unless you're in an overhead, the dive is over. Go to your other reg and surface. If the reg is free flowing and you can't shut it down, an inline shutoff is only 14 bucks at Piranha.
Or you can get the reg quick disconnect at DGX for 28.00 and it does seal when disconnected. LP reg hose is 20 at Piranha. But this only makes sense if you happen to have another second in your pocket with the same fitting. So three of them is 90 bucks.
One of the things I do with my AOW, rescue, tech, and solo students is take a hard look at their gear. They need to explain the benefits of everything they have and the possible downfalls. Not just how they work, but why they feel they need them. Anything that introduces problems or increases risk is gone. And they are told why.
There are quick disconnects used on full face masks for example. I have yet to see one on a "naked" second stage.
Tech divers will carry a wrench to swap seconds in an overhead but that usually means the stuff has hit the fan and there is one gas source that is compromised or is gone and taking it's second may be necessary.
the cheapest way is to just swap the stage and have an extra hose or two.

 

[Zef]

You're liable to be introducing additional failure points needlessly. Why would you want a quick disconnect on the inflator? Hoses are cheap. If you need to swap a second stage underwater, unless you're in an overhead, the dive is over. Go to your other reg and surface. If the reg is free flowing and you can't shut it down, an inline shutoff is only 14 bucks at Piranha.
Or you can get the reg quick disconnect at DGX for 28.00 and it does seal when disconnected. LP reg hose is 20 at Piranha. But this only makes sense if you happen to have another second in your pocket with the same fitting. So three of them is 90 bucks.
One of the things I do with my AOW, rescue, tech, and solo students is take a hard look at their gear. They need to explain the benefits of everything they have and the possible downfalls. Not just how they work, but why they feel they need them. Anything that introduces problems or increases risk is gone. And they are told why.
There are quick disconnects used on full face masks for example. I have yet to see one on a "naked" second stage.
Tech divers will carry a wrench to swap seconds in an overhead but that usually means the stuff has hit the fan and there is one gas source that is compromised or is gone and taking it's second may be necessary.
the cheapest way is to just swap the stage and have an extra hose or two.

Aqualung used to make the Calypso and Titan second stages in a quick disconnect model. It was mainly marketed for rental fleets and clubs where frequent cleaning and tool-less removal/installation was a consideration to save time between users. They were also sold to the general public. The major downside of the AL QD 2nd stages is that they require a hose with a propriety fitting or an expensive adapter that has the QD fitting on one side and is threaded to accept a regular LP hose on the other. The last I looked, the adapter was around $50US. My wife's first reg set had a pair of the QD 2nd stages and luckily we were able to purchase the adapter for our save-a-dive kit for about half the US price while we were living overseas. If we could go back in time and make the purchase again, we would avoid the proprietary QD 2nd stages all together.

-Z

 

[SlugLife]

You're liable to be introducing additional failure points needlessly. Why would you want a quick disconnect on the inflator? Hoses are cheap. If you need to swap a second stage underwater, unless you're in an overhead, the dive is over. Go to your other reg and surface. If the reg is free flowing and you can't shut it down, an inline shutoff is only 14 bucks at Piranha.
Or you can get the reg quick disconnect at DGX for 28.00 and it does seal when disconnected. LP reg hose is 20 at Piranha. But this only makes sense if you happen to have another second in your pocket with the same fitting. So three of them is 90 bucks.
One of the things I do with my AOW, rescue, tech, and solo students is take a hard look at their gear. They need to explain the benefits of everything they have and the possible downfalls. Not just how they work, but why they feel they need them. Anything that introduces problems or increases risk is gone. And they are told why.
There are quick disconnects used on full face masks for example. I have yet to see one on a "naked" second stage.
Tech divers will carry a wrench to swap seconds in an overhead but that usually means the stuff has hit the fan and there is one gas source that is compromised or is gone and taking it's second may be necessary.
the cheapest way is to just swap the stage and have an extra hose or two.

The main (theoretical) benefits I was thinking of at the time I created this thread was:

• Faster swapping from a minimalist side-mount or pony-bottle to/from a standard backmount setup.
• Easier and more compact storage.

However, since creating this thread, I also realized how easy it is to unscrew one hose or plug and install another.

The inline shutoff is probably more inline (pun intended) with pragmatic goals.

Aqualung used to make the Calypso and Titan second stages in a quick disconnect model. It was mainly marketed for rental fleets and clubs where frequent cleaning and tool-less removal/installation was a consideration to save time between users. They were also sold to the general public. The major downside of the AL QD 2nd stages is that they require a hose with a propriety fitting or an expensive adapter that has the QD fitting on one side and is threaded to accept a regular LP hose on the other. The last I looked, the adapter was around $50US. My wife's first reg set had a pair of the QD 2nd stages and luckily we were able to purchase the adapter for our save-a-dive kit for about half the US price while we were living overseas. If we could go back in time and make the purchase again, we would avoid the proprietary QD 2nd stages all together.

-Z

I ended up on piranah & dgx I noticed a bunch of different types of quick-disconnect styles, which only added to my confusion.

 

[Zef]

I think there are plenty of better things to spend money on in diving unless you are in the very small percentile who have an express need for the devices you are eyeballing...but there are also worse things in this world to spend money on as well.

-Z

 

[mdwalter]

I would like to have quick-disconnects between the 1st stage & the LP hoses. I have several octos I'd like to setup this way, making it possible to remove or swap both the inflator hose & backup 2nd stage regulator. I'd like to do this to a number of octos, if I can get the cost per fitting down enough.

If I'm understanding correctly, I'd need a 3/8-24 threads to Quick-Disconnect on the 1st stage side, then Quick-Connect to 3/8-24 threads?

• What size of fittings should be used? (Does anyone have a good scuba-fittings guide?)
• Should I be careful to ensure the female side of the quick-disconnect is one way and auto-closes? Or are they usually that way by default? For example, if swapping a 2nd stage regulator underwater (not that I expect to do that in the near future).
• What's the difference between "locking" and "non locking"
• Direct links where you can pick up the correct fittings inexpensively or in bulks are also appreciated.

My regulators and hoses are Scubapro MK10, G250, and Apeks AT20 & ATX200, and standard BCDs if that matters, so fairly standard threading and fittings. I've also ditched all of the oddball 1/2 size hoses/items.

Unless you can express a legitimate NEED to be able to change out octos, hose and all, right now, I would give a big fat "NO!" (or maybe even a "HELL NO!) to this idea. I'll leave it to the others to explain why this is a bad idea (failure points, complexity, adding clutter behind your head, etc.) and just focus on why it is completely unnecessary. If you want to use a different octo and hose on the next dive, I recommend you invest in a 9/16" wrench to simply swap it out in about 45 seconds at the surface. If you are happy to keep the hose, but want a different 2nd stage for the next dive, invest instead in an 11/16 inch wrench instead. And if you think you may want to do both of these things, get an adjustable wrench. Problem solved and you can do all the shopping at the Home Depot for like under $10.

If you really DO have a need to swap a second stage underwater, I would recommend the best way is still a wrench (but a small rust resistant one that you carry with you on the dive). If you REALLY have your heart set on QD, a better place to put the QD is at the 2nd stage end of the hose, and I would get a QC-6 for that. QC-6 will seal up on both sides when disconnected, has good positive lock-up when connected and will not restrict gas flow (that's why they use them on rebreathers). You won't be too happy with the price tag, though. It's about $95 for each half of the connector, so you're in for about $300 just to have 2 second stages and one hose to swap them out onto.

 

[SlugLife]

Unless you can express a legitimate NEED to be able to change out octos, hose and all, right now, I would give a big fat "NO!" (or maybe even a "HELL NO!) to this idea. I'll leave it to the others to explain why this is a bad idea (failure points, complexity, adding clutter behind your head, etc.) and just focus on why it is completely unnecessary. If you want to use a different octo and hose on the next dive, I recommend you invest in a 9/16" wrench to simply swap it out in about 45 seconds at the surface. If you are happy to keep the hose, but want a different 2nd stage for the next dive, invest instead in an 11/16 inch wrench instead. And if you think you may want to do both of these things, get an adjustable wrench. Problem solved and you can do all the shopping at the Home Depot for like under $10.

If you really DO have a need to swap a second stage underwater, I would recommend the best way is still a wrench (but a small rust resistant one that you carry with you on the dive). If you REALLY have your heart set on QD, a better place to put the QD is at the 2nd stage end of the hose, and I would get a QC-6 for that. QC-6 will seal up on both sides when disconnected, has good positive lock-up when connected and will not restrict gas flow (that's why they use them on rebreathers). You won't be too happy with the price tag, though. It's about $95 for each half of the connector, so you're in for about $300 just to have 2 second stages and one hose to swap them out onto.

I've since abandoned the quick-disconnect idea, and agree with pretty much everything here.

The other major issue is that quick-disconnects add a LOT of bulk to the regulator when stored. Part of my initial idea was using QDs to make disassembling my regulator and storing it compact easy, and the QDs actually achieve the opposite.

 

[Ross19966]

I wanted to put a QD on my FFM, but to make it a workable solution I would need a male end on my other Aqualung 2nd stage. The plan was to make the FFM and 2nd stage easily swappable without a wrench. The two issues I came up with are 1) An added failure point and 2) I thought the extra weight of the QD pulling on the Aqualung 2nd stage would get annoying. Not an issue with the FFM.

I've since abandoned the idea and just carry a wrench to swap out on the surface. Generally speaking, I'm not switching mid dive. Once I commit to the FFM, that's the way I roll for the entire dive.

 

[SlugLife]

I wanted to put a QD on my FFM, but to make it a workable solution I would need a male end on my other Aqualung 2nd stage. The plan was to make the FFM and 2nd stage easily swappable without a wrench. The two issues I came up with are 1) An added failure point and 2) I thought the extra weight of the QD pulling on the Aqualung 2nd stage would get annoying. Not an issue with the FFM.

I've since abandoned the idea and just carry a wrench to swap out on the surface. Generally speaking, I'm not switching mid dive. Once I commit to the FFM, that's the way I roll for the entire dive.

Precisely! Swapping with a simple wrench is so easy and fast, that at best you're saving 30 seconds, with 15 of those seconds being looking for the tool.

 

[Robert H. Diver]

Just seems like you’re creating a solution for a problem that doesn’t exist. I wouldn’t bother.