Atomic M1 vs ST1 reg for a rec diver toying with the idea of tec diving in the next 2-4 years

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eelnoraa

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Don't forget, the M1 also comes with the wider exhaust tee and an extra heat sink that is supposed to make them better in cold water.

The Z2 is great for single tank because it does have a LP port on the bottom, and it's pretty darn inexpensive. For any reg that might be used in something other than single tank, I would just buy M1s. I bought my Z2 set after I already had regs for doubles and knew that my Z2 set would be strictly dedicated to only single tank.
M1 exhaust T is nice. I have them on my travel rig, which is Ti2/B2 combo. But in reality, I don’t see much difference between M1 T vs B2 T. Both do the job. No bubble in face.

The heat sink, I also have it on all my B2 2nd. To me, it is more of a cool look. Not sure if it does anything. The only reason I have them is because I bought them for $5 each here many years ago. I bought 3.

I do feel the M1 face plate is a real but maybe small benefit when swimming against current. My B2 is tuned so hit it will flow with moderate current or when I am on DPV.

If I am starting new today, and don’t have the resource to buy used, I will buy z2 and call it good tho.
 

divezonescuba

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I use piston regs only, not a fan of diaphragm after seeing one blow at 300 feet. I have Ti2 for back gas and M1 for Deco bottles.
One manufacturer has a white bird cage like plastic object on top of the diaphram. I am wondering if that was how it originated.
 

stuartv

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Yes.

Metals are rated for how they burn with exposure to 7500 psi oxygen when the neoprene catches fire. If exposed to 80% O2, neoprene doesn’t burn hot enough for the Monel to burn. The monel burning isn’t self sustaining, but some is consumed with neoprene.

In reality, if your o-rings are Viton and not Neoprene, and your grease is O2 compatible, and your O2 is somewhat less than 7500 PSI, you should be fine. I expect Atomic was being hyper careful.

The report is here if you like reading that kind of thing…


Thank you so much for that!!

To make sure I'm clear, you're saying that the standard O-rings that come in an M1 are made of neoprene? that seems pretty evident from the later part of your post, but when I read the first paragraph I kept thinking "why is he talking about neoprene in the 1st stage?"

So, if you want M1s serviced with Viton O-rings, is there an option for that other than total DIY? Like, does anybody sell a kit like that? Or, would a place like Air Tech be able to service them that way?

I'm particularly interested because I need to get my M1s serviced right now anyway...
 

Wookie

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Thank you so much for that!!

To make sure I'm clear, you're saying that the standard O-rings that come in an M1 are made of neoprene? that seems pretty evident from the later part of your post, but when I read the first paragraph I kept thinking "why is he talking about neoprene in the 1st stage?"

So, if you want M1s serviced with Viton O-rings, is there an option for that other than total DIY? Like, does anybody sell a kit like that? Or, would a place like Air Tech be able to service them that way?

I'm particularly interested because I need to get my M1s serviced right now anyway...
No. All atomic kits include viton o-rings in the important places.

But that doesn’t stop someone from using a neoprene o-ring in say the DIN connection on the boat, etc. Or building the regulator with aftermarket parts.

I tend to stay away from the big rebuilding services unless they tell me that they are using factory kits. Factory kits are extremely expensive, and a facility building 10’s to hundreds of regulators can save thousands of dollars a month sourcing parts from o-ring vendors. I do it myself (my main engine heat exchangers use 4 each of a $200 factory o-ring that I can get on Amazon for $4).

I do not do that on regulators I repair for other people, but I would completely understand the temptation.
 

stuartv

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No. All atomic kits include viton o-rings in the important places.

But that doesn’t stop someone from using a neoprene o-ring in say the DIN connection on the boat, etc. Or building the regulator with aftermarket parts.

So, out of the box, the M1 is just as O2-compatible as any other scuba reg that is sold as being O2-compatible?
 

Wookie

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So, out of the box, the M1 is just as O2-compatible as any other scuba reg that is sold as being O2-compatible?
No. Brass is far more oxygen compatible than Monel. It’s the nickel that screws up the monel. So your statement is incorrect because a brass regulator is far more compatible with oxygen than a Monel regulator is.

Brass regulators are 100% oxygen compatible, and oxygen regulators are made of brass. The M1 is only compatible with 80% oxygen.
 

stuartv

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No. Brass is far more oxygen compatible than Monel. It’s the nickel that screws up the monel. So your statement is incorrect because a brass regulator is far more compatible with oxygen than a Monel regulator is.

Brass regulators are 100% oxygen compatible, and oxygen regulators are made of brass. The M1 is only compatible with 80% oxygen.

I gotcha. Thank you for all the clarification.
 

eelnoraa

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Brass regulators are 100% oxygen compatible, and oxygen regulators are made of brass. The M1 is only compatible with 80% oxygen.
Wait. Really??? I thought 80% is just AA lawyer writing the documents. If monel is bad, why use it in the first place? Brass has been around and inexpensive, why reinventing the wheel?
 

Wookie

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Wait. Really??? I thought 80% is just AA lawyer writing the documents. If monel is bad, why use it in the first place? Brass has been around and inexpensive, why reinventing the wheel?
Brass corrodes in salt water. Monel not so much.

I’d bet that the 80% limit IS an Atomic lawyer writing the documents.
 

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