Oh, this is going to be good

[LUBOLD8431]

mmakay once bubbled...


Do you have any proof of this? Can you explane why it would be true?

Well, unfortunately, not really. If you look at Rodale's latest tests on a simulator for a whole bunch of different regs, all it says is if a reg achieved the 198 foot mark, with less than a 1 joule W.O.B. Most of the regs, both piston and diaphragm in the over $400 range met this goal.

That is not proof of a diaphragm being a better breather than piston. I know that... It actually shows that the scubapro pistons performed "excellent" in all of the tests.

The difference shows in deeper than 200 feet. Unfortunately, there are no measured ratings for beyond 198 feet. Because, as we all know, that is pretty damn deep, and not many people are going beyond that depth...

 

[Warren_L]

Well, as someone fairly new and knowing little, it seems like the diaphrams are the way to go, based on what I want from it. As someone said earlier, you mileage may vary......

 

[mer]

I just bought my first reg set this fall and chose a diaphram first stage (scubapro MK16 S550 with R380 octo).

Being a poor ex-student who often dives in silty water as cold as 40deg F, I went with the diaphram (MK16 over M25). Even though I only have 10-15 dives on the set, with a max depth of 65 feet, I am happy with the performance so far.

I thought I had done pretty thorough research, but I never came across the failure position of each type of reg (diaphrams fail closed, pistons fail open). Seeing that I had a very length debate with my LDS about the dis/advantages of each... but that's another b*tch.

I guess now, I'm putting my faith in that good maintaince combined with an "environmentally sealed" reg will keep that failure from happening in the first place.

-mer

 

[undah20]

As a side note...

on the "Blue" color of the orings on the piston, it is not because of contact with salt water. (by the way, salt water leaves green residue - like on the filter (very rare to see green on the piston orings). Gray on the filter from oils and contaminents, red(rust color) from moisture - bad air sources.)

Anyway, the blue you saw was the discoloration from the Christolube used to lubricate those areas. Ive seen that quite common along with PINK colors on the hose threads as well. I haven't been told if it's a 'bleeding' of color from the oring into the surrounding normal white-ish color of the Christolube or not. I wouldn't have normally thought it be the case as Scubapro uses EDPM orings which are typically much better quality than most of the orings out there. I would think the harder dirometer of materials wouldn't bleed color as easily, but I'm not sure of the reaction of compounds from the Christolube? Christolube is a VERY stable compound - (ie read the material spec sheets from it.)

I've seen that 'Blue' tons of times and it has nothing to do saltwater. Many of the regs have never seen saltwater.

 

[JCKCSYCMD]

Verbshark once bubbled...
First, you said, "The pro-piston guys will tell you...."

I pointed out why your were incorrect in your assessment.

Second, you haven't given me two advantages--you've given me one. Since I'm not diving in cold water (which to me means anything below about 55F), cold water advantages are a non-issue.

Ho hum.

Somehow 55F does not strike me as cold. Diving the Great Lakes, some sections don't get that high by late August. When I think of cold it is just before Christmass pulling the last of the moorings, the club ice dives, a through ice recovery search, and right after the ice goes off.

 

[ZoCrowes255]

LUBOLD8431 once bubbled...
Thats like asking what do you like, Chevy or FOrd???

Thats just one of those questions that you will get split right down the middle...

The PRO-Diaphragm people are goin to say that they are better for cold water and that the inside stays alot cleaner, meaning less cleaning (and easier for the tech servicing your reg, not too much time in the ultrasonic). And better performance at depth... Which by the way, the deepest open circuit scuba dive EVER done was using a DIAPHRAGM regulator (actually alot of them).

The Pro-Piston guys will tell you that the newer pistons work just fine in cold water, cuz they got this new fandangled thang called a thermal isolaater protectur thingy that'll just kinda set there and portec that lil ole piston... Also, they are a fail safe design, which means that if they fail, they fail open (freeflow). If you have a failure of the diaphragm on a D reg, they fail CLOSED, which means, uhhhh, sorry no air today bubba... And they will also say, pistons are more rugged and need less tweaking and tuning and are a workhorse reg...

I say, get a diaphragm... I HATE piston regs...

Well the only regulator brand I will ever dive is Scubapro and the Mk25 is head and shoulders above the Mk16. The breathing rate is about the same but the pistons are so much easier to work on and are more rugged. Plus they just look cooler and isn't that what it's all about :mean:

 

[ElectricZombie]

ZoCrowes255 once bubbled...

Mk25 is head and shoulders above the Mk16. The breathing rate is about the same but the pistons are so much easier to work on and are more rugged.

The Mk25 is not really "head and shoulders" above the Mk16. (I own 2 Mk25s BTW) Performance wise, you will not be able to tell a difference between the two. The Mk25 has a higher flow rate and will test better on paper. You can't expect a diaphram reg to have the same flow rate as a piston reg. ScubaPro and most LDS push the Mk25 simply because it is more expensive. It is a great reg but, so is the Mk16. The Mk25 has a lot of small parts so, it often will take longer to do a Mk25 than a Mk16. Both are easy to service though. Pistons are more resiliant if flooded but, for recreational diving this does not really come up. However, they are more prone to internal corrosion and getting sand, etc lodged inside. The Mk16 will not have these problems. (Proper care eliminates this with the Mk25 though.) The Mk25 has good doubles hose routing options and the Mk16 isn't too bad either.

Both are great regs, both have pros and cons. However, they are equal in term of performance. They only way you could ever tell a difference is if you hooked the regs up to a machine for testing. I dive both and can't tell any difference between them.

 

[JCKCSYCMD]

Machines can register differences, but one would be hard pressed to detect the difference between my 28 yr old Suba Pro Mark V, my son's year old M25s. With that in mind with pistons, they also appear to breath the same as my Atomic M1. But after all basically the same designers. Other than the durable weighty Mark V 2nd stage...which regulator are you using?

We also have some diagphram regs and in my opinion, the USD Titans for the money are a heck of a unit.

 

[ZoCrowes255]

ElectricZombie once bubbled...


The Mk25 is not really "head and shoulders" above the Mk16. (I own 2 Mk25s BTW) Performance wise, you will not be able to tell a difference between the two. The Mk25 has a higher flow rate and will test better on paper. You can't expect a diaphram reg to have the same flow rate as a piston reg. ScubaPro and most LDS push the Mk25 simply because it is more expensive. It is a great reg but, so is the Mk16. The Mk25 has a lot of small parts so, it often will take longer to do a Mk25 than a Mk16. Both are easy to service though. Pistons are more resiliant if flooded but, for recreational diving this does not really come up. However, they are more prone to internal corrosion and getting sand, etc lodged inside. The Mk16 will not have these problems. (Proper care eliminates this with the Mk25 though.) The Mk25 has good doubles hose routing options and the Mk16 isn't too bad either.

Both are great regs, both have pros and cons. However, they are equal in term of performance. They only way you could ever tell a difference is if you hooked the regs up to a machine for testing. I dive both and can't tell any difference between them.

Most of my experiences with them have been with servicing them and tinkering with my own (1 Mk25, 2 Mk 15, 1 Mk16 and an old Mk2) and I can put together a piston first stage in my sleep. I also like the swivel first stage on the 25 (and the diaphragm 18.)

I think I base more of this on the fact in that I have a hard time comprehending exactly how a diaphragm design works. Care to explain it to me because I can't ever seem to get the time to get Kevin to.

 

[Compressor]

Scubapro all the way. They are solid regulators with an excellent warranty program. The simplicity of pistons cannot be beaten.