Scubagaskets getting into the Reg business

[Tanks A Lot]

...This SG one being stainless is interesting....

What I find concerning is that their first stage ScubaGaskets NSGT2 (HotDive ST2O2), is in essence the ScubaGaskets SGT2 (HotDive S2). Presumably all they changed was the O-Rings and hopefully seat material, but this is meant to be an oxygen compatible regulator. This regulator is still made from stainless steel - a poor choice for an O2 environment.

Stainless steels are used in oxygen environments and the austenitic steel 316 that this regulator is made of, is one of the better choices when it comes to stainless steels in an oxygen environment. Nevertheless it is far inferior in an high pressure oxygen environment than copper, nickel or their alloys, like brass.
In industrial O2 piping systems, it is not uncommon that stainless steel has a protective liner of copper, nickel or Monel alloys.¹ Brass is generally considered inflammable for most configurations. It has great characteristics for the job.

Especially when it comes to impact ignition, stainless steels are very poor, compared to e.g. brass. The following test shows this quite clearly:

²

Materiala	Highest Temperature without Ignition (°C)	Lowest Temperature with Ignition (°C)
Monel K500 (heat treated)	371e	None
Monel K500 (annealed)	371e	None
Haynes 214	371e	None
Monel 400	343e	None
Incoloy MA 754	343e	None
Yellow brass	316e	None
Inconel 600	316e	None
Tin-bronze	288e	None
Aluminum-bronze	260	316
Inconel 625	260	316
440C SS (annealed)	177	204
Inconel 718 (annealed)	149	204
Ductile cast iron	149	204
Incoloy 800	121	204
Incoloy 903	93	121
Haynes 230	38e	None
Nitronic 60	–18	121
316 SS	10	38
304 SS	–18	38
Incoloy MA 956	–46	10
13-4 SS	None	10
14-5 PH SS	None	10
6061 Aluminum	None	–46

^aThe targets were configured in a cup-like shape. The thickness of the surface exposed to the impacting
particles was 0.15 cm (0.06 in.).
^eIndicates that the material did not ignite at the highest temperature at which it was tested

Similar tests have been done over and over again, with stainless steels showing clear inferior characteristics for oxygen service compared to brass. Stainless steel ignites at far lower pressures, with far lower temperatures and it burns much hotter. A report from ASTM underlines this.³

Metal	Thresholda Pressure (MPa)	Hcb (J/g)	Particle Impactc (°C)	Frictional Heating (W/m2)
Brass 360	>70	6,000	>371 (NIe )	0.70–1.19
Nickel 200	>70	4,100	¯	2.29–3.39
Copper 102	>55	2,500	¯
316 Stainless	3.4	7,900	38	0.53–0.86
Tin-bronze	>70	¯	>371 (NI)	2.15–2.29
Monel 400	>70	3,642	>371 (NI)	1.44–1.56
Monel, stainless steel (thin section)	0.1d	¯	¯	¯
Carbon steel	0.2	7,500	¯	0.27–0.32
Aluminum	0.2	31,400	-46	0.061

^a Threshold pressures of metals are based on 3.2-mm diameter rod data per ASTM G124.
^b Heat of combustion
^c Bulk sample temperature required for ignition by aluminum particle impact at supersonic velocities.
^d Thin sections of Monel and stainless steel have been shown to self-sustain combustion at ambient pressure e.g., wire mesh.
^e No ignition.

I'm not advocating that stainless steels are unsafe in a high O2 environment, they are regularly used in industrial piping systems and even certain medical regulators. But stainless steel piping has other advantages, where brass would be impractical and we are talking about a SCUBA regulator here, not piping.
Brass is a much safer choice for an O2 regulator and we are not operating in a strict regulated industry. While industries often adhere to strict protocols, standards and timetables, the SCUBA industry generally does not. This stainless steel regulator in and of itself of course does not ignite, but it adds an element to the things that have to go wrong to cause an O2 fire.

The CE certificate shown is borderline useless, as it just lists standards which involve material composition, e.g. that there is no mercury in it. On a positive note, the regulators seems to be EN250:2014 conform, although I can't find the certificate. It is noted in their manual though.
Furthermore they state that EN250:2014 compliant regulators are not meant to be used below 10°C.

Standard EN 250:2014, while regulating the minimum safety requirements for an Octopus, similarly discourages the use of an Octopus for dives conducted in water temperatures below 10 °C. It does not consider this configuration ideal for those conditions, and instead recommends the use of two complete regulators that are separate from each other, to be connected to a valve that offers two independent ports.

This is flat our wrong. EN250:2014 states:

If a demand regulator is intended to be used at water temperatures below 10 °C, its performance at 6 bar absolute pressure and in water at 4 °C, and at a lower temperature if specified by the manufacturer, shall meet the requirements of 5.7.1 in the upright position. If a demand regulator is intended to be used at water temperatures below 10 °C, its performance at 6 bar absolute pressure and in water at 4 °C, and at a lower temperature if specified by the manufacturer, shall meet additionally the requirements of 5.7.1 a), b) and c) in the swimming position at the maximum sensitivity control setting.
Test in accordance with 6.7.2.

6.7.2 Cold water performance
Apparatus and sub-assemblies intended for use in water temperatures below 10 °C shall be immersed and tested as ready-for-use apparatus in fresh water at a water temperature of 4_0/-2 C° at a depth of at least 0,2 m for 5 min at 6 bar absolute pressure. The demand valve shall be rigged as though the diver’s head were in both the upright and the horizontal face down (swimming) position respectively.
The air exhaled by the breathing simulator shall be heated and humidified. The air temperature shall be (28 ± 2) °C and the relative humidity greater than 90 % throughout the test when measured at the interface with the demand valve. The cylinder(s) used for the test of the demand regulator shall have an internal volume of 14 +1/0 l. They shall be charged to the maximum rated working pressure of the regulator. If the rated working pressure of the regulator is less than 200 bar, the cylinder(s) when charged to the rated working pressure of the pressure reducer shall contain sufficient air to complete the test and shall not be discharged to less than 50 bar.

This is by no means the only misrepresentation of EN250:2014 in this document...

I'm less than impressed what ScubaGaskets offers here. They sell their SGT2 for 399€ (Supposed to cost 499€ later). The very same regulator I get from HotDive directly for 360€. As SCUBA gasket only dropships, they have not even imported the regulators into the EU, so customs duty will apply to both. I have a funny feeling of why they have not been imported to start with... The import duties will be much higher for the higher priced item.
This coupled with the sloppy use of stainless steel for the O2 regulator, makes me think that virtually no thought has been put into this, other than a couple of logos onto a pre-made regulator. A company that touts itself with 30 years of experience in O-Rings, should have been more involved in the SCUBA industry and should know better.
Additionally the poor owners manual and flat out misrepresentation of standards is an absolute no-go for me.

It seems nothing like a money-grab to be quite frank.


¹ European Industrial Gas Association AISBL - Oxygen Pipeline And Piping Systems (2012) - Page 13
² Safe Use Of Oxygen And Oxygen Systems (2000) - Page 38
³ ASTM - Flammability And Sensitivity Of Materials In Oxygen-Enriched Atmospheres (2010) - Page 301

 

[The Chairman]

Why is SS better than chromed brass?

Verdigris, that green stuff, is the brass equivalent of rust and is also caused by exposure to oxygen. The chromed outside looks great, but the insides not so much. I have yet to encounter a chromed brass reg that doesn't have verdigris in its innards. It's pretty much a given. I have yet to have any of my SS regs rust. Sure, they can as they have a high iron content, but I have yet to encounter it on my regs, even on the inside.

These regs look good. I hope to try them some day.

I need a replacement 1st stage for my SF2 rebreather. I have a HOG in there that doesn't quite work. That O2 reg looks sweet.

 

[BoltSnap]

@Scubagaskets

 

[Mobulai]

Regarding the piston, I found on hot dive‘s IG this short video of the disassembled view, the piston shows for mere couple of seconds— but there’s a chance it’s a knife edge
I might just get it (the hotdive one, since they sell have the option for the 1st on its own) just to have a spare piston for my mk10s
Worst comes to worst I end up with an mk10+ configuration

 

[lowwall]

Regarding the piston, I found on hot dive‘s IG this short video of the disassembled view, the piston shows for mere couple of seconds— but there’s a chance it’s a knife edge
I might just get it (the hotdive one, since they sell have the option for the 1st on its own) just to have a spare piston for my mk10s
Worst comes to worst I end up with an mk10+ configuration

If you do, please let us know what you think of it.

 

[rsingler]

I am currently evaluating this regulator for Scubagaskets, and am completely rewriting the admittedly poor factory manual.
Narwhal is a somewhat new company, having been active for about 10 years.
The regulator I received yesterday has extremely nice fit and finish, and the threading of the cap and HP Seat Carrier is extremely well done.
As @The Chairman pointed out above, there is scattered rust in this year-old hard-dived sample that I was sent for testing, but none of the degradation of chrome that is found under verdigris. The use of 316SS for this price is indeed intriguing.
The design is indeed similar to the venerable Mk10, and the knife edge is a modified sharp edge, with the seal made at the square corner of the easily-polished piston and the conical seat.

The owner of Scubagaskets is indeed intent on having a quality piece of equipment, and we are already making subtle modifications to ensure serviceability. He plans to make the service manual and parts available to the end user, with it being the user's responsibility to ensure adequate training for regulator servicing.
Given the range of quality available on the current import market, I'm impressed with this one. It's a proven design, and 316SS offers some real advantages, given most divers sloppy post-dive maintenance habits.
The second stage is a standard end-balanced poppet, but again, the barrel is 316SS. As with the first stage, knob-to-barrel threading is extremely smooth, and a far departure from the quality of similar imports. The stabilizing bosses for the barrel in the case are sturdy, protecting the reg from the barrel rotation that plagued the flimsier HOG Classic. The GRP in the case feels sturdy.
The reg set has indeed met EN250:2014, and the certificate will be published.
I can't speak to the suitability of 316SS for the O2 reg, as I don't know the seat material.

In short, this appears to be a good value on the basis of the manufacturing quality I am seeing thus far. And I always loved the Mk10. It even has the SPEC groove that DIY'ers might take advantage of.

I believe Scubagaskets has further plans on the diaphragm side, and having a 316SS reg available at reasonable cost there would be significant.

Stay tuned.

 

[lexvil]

I am currently evaluating this regulator for Scubagaskets, and am completely rewriting the admittedly poor factory manual.
Narwhal is a somewhat new company, having been active for about 10 years.
The regulator I received yesterday has extremely nice fit and finish, and the threading of the cap and HP Seat Carrier is extremely well done.
As @The Chairman pointed out above, there is scattered rust in this year-old hard-dived sample that I was sent for testing, but none of the degradation of chrome that is found under verdigris. The use of 316SS for this price is indeed intriguing.
The design is indeed similar to the venerable Mk10, and the knife edge is a modified sharp edge, with the seal made at the square corner of the easily-polished piston and the conical seat.
View attachment 838288
The owner of Scubagaskets is indeed intent on having a quality piece of equipment, and we are already making subtle modifications to ensure serviceability. He plans to make the service manual and parts available to the end user, with it being the user's responsibility to ensure adequate training for regulator servicing.
Given the range of quality available on the current import market, I'm impressed with this one. It's a proven design, and 316SS offers some real advantages, given most divers sloppy post-dive maintenance habits.
The second stage is a standard end-balanced poppet, but again, the barrel is 316SS. As with the first stage, knob-to-barrel threading is extremely smooth, and a far departure from the quality of similar imports. The stabilizing bosses for the barrel in the case are sturdy, protecting the reg from the barrel rotation that plagued the flimsier HOG Classic. The GRP in the case feels sturdy.
The reg set has indeed met EN250:2014, and the certificate will be published.
I can't speak to the suitability of 316SS for the O2 reg, as I don't know the seat material.

In short, this appears to be a good value on the basis of the manufacturing quality I am seeing thus far. And I always loved the Mk10. It even has the SPEC groove that DIY'ers might take advantage of.

I believe Scubagaskets has further plans on the diaphragm side, and having a 316SS reg available at reasonable cost there would be significant.

Stay tuned.

Happy to hear that you’ve got one in hand, there are some nice features, Stainless, a compact turret and a Stainless no turn barrel in the second really sweetens the prospect toss in the access to service kits and parts makes it coma inducing sweet

 

[Tanks A Lot]

I am currently evaluating this regulator for Scubagaskets, and am completely rewriting the admittedly poor factory manual.

That is great to hear.

I can't speak to the suitability of 316SS for the O2 reg, as I don't know the seat material.

I want to reiterate that my objection is not to the "soft" parts inside, of which I have no way of knowing what they are, but the 316 steel as a choice for an O2 regulator. It is a poor choice for the job intended. It adds something unnecessary that has to go wrong for an O2 incident to happen. Brass would be the safer choice.

I feel like ScubaGaskets should have ironed out some of these things before putting them up for sale.

 

[andrewmcc]

@rsingler any chance you will dive one of these for 9 years without servicing it like you did with a MK10?

 

[rsingler]

@rsingler any chance you will dive one of these for 9 years without servicing it like you did with a MK10?

That's a fair question! There's no reason I can't strap a bicycle inner tube over that deep groove and fill the thing with Tribolube. Now the insides are protected indefinitely, if my fill has no bubbles.
But that said, two other factors now become important:
1) I am discovering that pistons are inherently more susceptible to knife edge degradation from tank particulates. I think that's what finally happened to my old Mk10, though we'll have to wait and see what the piston looks like when I open it up.
2) "no service for 10 years" is a little misleading. I removed and replaced the yoke bolt every year. When mfrs went from an oring seal at the neck of the bolt (that protected the threads from exposure to seawater) to one at the end of the bolt, then verdigris corrosion of the bolt threads makes yearly removal a good idea.

Yeah, I'll probably seal this reg, if only to maintain my reputation as a Mk25 hater, because performance aside, that fantastic reg is not seal'able.