Atomic B2 and M1 Questions

[Pressure Group X]

Greetings all...please pardon my “rookieness” as this is my first post but I am feverishly looking for information for a pending Atomic M1 purchase.

I currently own an unsealed, Atomic B2 with a yoke first stage. I love this regulator and have no complaints nor issues but am looking into the M1 after a recent “cold” water dive.

Three things became immediately obvious to me after this “cold” water dive:

1). After thinking I would NEVER want to dive cold water...I am now looking to continue diving in colder waters and pursue further training in colder after diving. While my dive was a mere 84’ in 54 degree water, it was absolutely invigorating and the usual TX waters being next to boiling are now of little interest to me.

2) “Cold” is a very relative term. What one diver considers cold, another may consider to be a hot tub...Because if this, I am wondering how cold / deep is safe for an unsealed B2?

3) At what point should I truly consider a new “cold water” setup?

I am very interested in an M1 with a DIN first stage. Any insight is appreciated...

 

[rsingler]

Hi! Welcome to ScubaBoard! This is a place where you'll find a thousand opinions, all of them right. We hope you post often.

Re: the Atomics, they're a fantastic, precision manufactured regulator. But they are all identical! Yes, one has zirconium plated brass, one has stainless, one has titanium, but the designs are identical. They all perform the same.

So when it comes to cold water, the M1 has little to recommend it over the others except for a huge chunk of metal to secure the reg barrel to the body. That might be a nice heat sink!

There's more info on their website, but the M1 was introduced for high oxygen technical diving. They have substituted Monel and stainless for a few bits of titanium that theoretically have a lower ignition point in high pressure oxygen. I use two DIN sets for some of my tec diving.

For true cold water diving, I'll defer to some of the Great Lakes and Northeast members, but I would have zero hesitation diving an unsealed Atomic down to 48°F or lower. It's all about technique, and perhaps lowering the Intermediate Pressure of the first stage a bit. But there's nothing really to recommend the M1 over your B2.

And of course, you could always seal them, which I do for ALL my Atomics, mostly to keep grit out of the ambient chamber. But that's another story, about which I'm a bit of a fanatic.

Cheers, and welcome to SB!

 

[saxman242]

If you keep an eye out on ebay, you can occasionally find the din conversion kits for ~$50 or so. Worst case scenario, MSRP is about $100 for it. It just replaces the yoke fitting. Put that on and seal the reg and you essentially have the same thing as an M1, as long as you're not using it for high 02% use.

 

[Ouvea]

Rslinger has convinced some of us to seal the first stages of our Atomic regulators. However, we do so to protect the piston land of the first stage body. Also makes cleaning the regulator, after each dive, much easier and simpler, as I don't sit there trying to flush the ambient pressure chamber with fresh water after soaking the unit. Presently, I dive in Monterey/Carmel, off the coast of California. The water temperature averages 50F, although I have seen it drop down to 46F on some occasions. In the winter, the air temp can drop down to high 30Fs and low 40Fs. Never experienced any issues. If your diving conditiosn and topside conditions mirror these, you won't have any issues with your current setup.

Also, if you want to seal the first stage of your regulator, you do not need to purchase an M1. Your LDS can inject the Christolube lubricant and install the sealing boot. If you look at Atomic Aquatic's website, you can purchase the Z2,Z3 or B2 sealed or unsealed.

 

[Pressure Group X]

So in y’alls experience...Is there a depth or temp that tilts the scales to “needing” an M1 vs a sealed B2?

 

[saxman242]

So in y’alls experience...Is there a depth or temp that tilts the scales to “needing” an M1 vs a sealed B2?

Not really. More of a use case issue. High 02 or no high 02. You can add the M1 heat sink to your B2 second stage very easily if you so desire.


Unless you can get a good conditioned, used M1 for under the cost of the DIN adapter, or you just want/need to have a second reg, I don't see a good reason to pick up an M1 over what you currently have. Any used M1 should be serviced, so the cost of servicing it vs sealing your current B2 is a wash, so the only difference is really the din adapter.

 

[rsingler]

Perhaps I was too verbose. An unsealed M1 offers no better cold tolerance than any other unsealed Atomic. Except perhaps for that nut, which probably doesn't really add much.
And a sealed M1 is not better in cold water than a sealed B2.
I can't believe I'm saying this, but if you're committed to unsealed, and wanting to add insurance for cold water, then maybe the Scubapro Mk25EVO has a tiny advantage with its coated spring and squishy bushing that helps crack ice off the shaft.
Everyone knows I'm no fan of the Mk25 because you can't seal it. But if you want unsealed for cold, it's one thought. Not my choice.

I'd recommend you just seal your B2, add a DIN and dive away! I haven't serviced my sealed first stage in 3 years, and the IP is rock steady. I don't plan to open it up until I see some change in my IP checks.

Ah! @saxman242 beat me to it!

 

[Pressure Group X]

Appreciate the input...I’ll go ahead and seal it and stay on a yoke until a recent deal shows up.

I’m also considering grabbing an M1 and using the B2 as an octo...Like Yogi said, “when you come to a fork in the road..take it”

Thanks again!

 

[saxman242]

Appreciate the input...I’ll go ahead and seal it and stay on a yoke until a recent deal shows up.

I’m also considering grabbing an M1 and using the B2 as an octo...Like Yogi said, “when you come to a fork in the road..take it”

Thanks again!

Be careful... I've found that they tend to multiply when you start buying more than one. Ha!

 

[Scared Silly]

To echo what has been said, just seal your B2 and go dive it. A side question, what is your backup second stage? IMHO having a backup second stage that is equal to your primary second stage is important when diving. I ask as you mention using the B2 as your backup in the future.