What is the most bulletproof 1st stage of all time?

[Rusty Shackleford]

Still, for all the love that Deep6 gets and all the Scubapro hate that I'm happy to join in on, it's interesting to see what has stood the test of time.
I don't think many would say that the Mk2 is the best performer, but for 2 orings and a seat, you can't beat simple.

it may not be the best but with a properly set up balanced second, damned if I can tell the difference.

It is the Kalashnikov of 1sts. Not the best in features but top notch reliability.

 

[rhwestfall]

I have a 109/156 on it. I like to be able to adjust it in, and be able to breath a nice reg if/when it is needed.

And, you can drive nails with it and not be worried (except maybe breaking the nail....)

I also think it can be used to chock the wheels of the boat trailer at the launch ramp if needed...

 

[Jcp2]

Wouldn’t a Sherwood with a clogged dry bleed filter be effectively an unplanned simple piston Mk2 equivalent. If so, why not choose the Sherwood for this additional benefit?

 

[Bob DBF]

Wouldn’t a Sherwood with a clogged dry bleed filter be effectively an unplanned simple piston Mk2 equivalent. If so, why not choose the Sherwood for this additional benefit?

It was a Sherwood engineer, back in '58 that modified their surface piston regulator to work underwater, which was the beginning of the two stage scuba piston regulator which several scuba brands picked up. Sherwood manufactured parts or entire regulators for every, or nearly every early scuba brand, as they were the major manufacturer of quality high pressure gas equipment in the US, well before they had a scuba brand.

Since Sherwood never restricted the use of their patent, probably because it was good for their business, I wouldn't be surprised if the MK2 isn't a close derivative of the original Sherwood design.

 

[rhwestfall]

It was a Sherwood engineer, back in '58 that modified their surface piston regulator to work underwater

IIRC, here in Lockport/Wheatfield/Tonawanda (Buffalo), NY....

 

[BoltSnap]

Tonawanda

I was there once when I was at RIT.

 

[Pressurehead]

My safety aka ‘buddy’ bottle has a MK-2. I keep it clean and only service it about once a decade. It never complains and always delivers. I did upgrade the R-190 to a cheap HOG Classic 2.0 that I came across at a price I couldn’t resist.

I wanted to be able to de-tune it as opposed to keeping it shut off.

I used it yesterday in fact.

I have a 109/156 on it. I like to be able to adjust it in, and be able to breath a nice reg if/when it is needed.

Had a R190 on it and changed to a R195 [we are still talking about Mk2 s ], I do have a couple of G250 or the spare S600 , but stayed with basic and simple for my "buddy", [he is not the sharpest pencil in the box].

 

[2stroketony]

Might help if I read the post correctly.
1st stage, my vote would be a mk5 scubapro.

UOTE="2stroketony, post: 9423708, member: 417868"]Oceanic Omega 2. Simple, dependable, user serviceable, great performer.[/QUOTE]

 

[rsingler]

Wouldn’t a Sherwood with a clogged dry bleed filter be effectively an unplanned simple piston Mk2 equivalent. If so, why not choose the Sherwood for this additional benefit?

Unfortunately not. When the bleed filter is blocked, the reg effectively becomes a surface paint shop regulator. It loses its ambient sensing, because the top hat seal that normally bubbles continuously (26 cc/min) during a dive seals shut. Or worse, it doesn't quite seal shut and the reg fills with seawater as ambient pressure increases.
Thus, a regulator that starts, say, with an IP of 135 at the surface, but no ambient sensing, drops to a relative IP of 120 at 33 feet. The 14.7psi of the extra atmosphere of depth is transmitted back via the second stage circuitry, and opposes the absolute IP coming from the first. With a balanced second stage, you may or may not notice anything.
By the time you reach 99 feet, the ambient pressure has increased 44 psi. That means a relative IP of 91 psi, and your regs will be breathing a bit (or a LOT) stiffer. Mares seconds, which are still unbalanced, would hardly work.
If you happened to take your Sherwood to the sand at the Spiegel Grove in Key Largo at 135 feet, the increase in ambient pressure is now enough to leave you with a relative IP of 75psi. Only an old Scubapro D-400 (and maybe their new D-420) wouldn't care about a relative IP of 75.

That was the fantastic thing about Sherwood's design. It used 500-3000 psi tank pressure to allow air to continuously bleed a calibrated amount of gas into the ambient chamber, keeping out seawater. No worries about corroded piston lands! You probably couldn't descend fast enough to overcome the bleed rate as it maintained your relative IP. Even a partially clogged filter would still work. The bleed would just be slower, and you might have noticed a little stiffening during a hot drop, which disappeared as the ambient chamber caught up to true ambient outside the reg. Very cool design, even if most folks thought "your reg is leaking!" Alas, shop monkeys were always letting silicone lube clog up the filter. Fortunately, enough bleed gas always seemed to get through that folks didn't die.

 

[Eric Sedletzky]

Unfortunately not. When the bleed filter is blocked, the reg effectively becomes a surface paint shop regulator. It loses its ambient sensing, because the top hat seal that normally bubbles continuously (26 cc/min) during a dive seals shut. Or worse, it doesn't quite seal shut and the reg fills with seawater as ambient pressure increases.
Thus, a regulator that starts, say, with an IP of 135 at the surface, but no ambient sensing, drops to a relative IP of 120 at 33 feet. The 14.7psi of the extra atmosphere of depth is transmitted back via the second stage circuitry, and opposes the absolute IP coming from the first. With a balanced second stage, you may or may not notice anything.
By the time you reach 99 feet, the ambient pressure has increased 44 psi. That means a relative IP of 91 psi, and your regs will be breathing a bit (or a LOT) stiffer. Mares seconds, which are still unbalanced, would hardly work.
If you happened to take your Sherwood to the sand at the Spiegel Grove in Key Largo at 135 feet, the increase in ambient pressure is now enough to leave you with a relative IP of 75psi. Only an old Scubapro D-400 (and maybe their new D-420) wouldn't care about a relative IP of 75.

That was the fantastic thing about Sherwood's design. It used 500-3000 psi tank pressure to allow air to continuously bleed a calibrated amount of gas into the ambient chamber, keeping out seawater. No worries about corroded piston lands! You probably couldn't descend fast enough to overcome the bleed rate as it maintained your relative IP. Even a partially clogged filter would still work. The bleed would just be slower, and you might have noticed a little stiffening during a hot drop, which disappeared as the ambient chamber caught up to true ambient outside the reg. Very cool design, even if most folks thought "your reg is leaking!" Alas, shop monkeys were always letting silicone lube clog up the filter. Fortunately, enough bleed gas always seemed to get through that folks didn't die.

I had a Sherwood Brut. I bought it brand new as a pony reg.
The dry bleed stopped working on it. I think it might have been because I used it as a stage bottle reg and the protocol was to pressurize it then shut it off. Taking it to depth probably pressed salt water back into the dry bleed hole and corroded it shut. At the time I didn’t know any better, I should have left it open just a tick and it would have been fine.