Why do piston regs cost more than diaphragm regs?

[Eric Sedletzky]

What about the cold water divers, though? I'm diving sealed diaphragms because everyone gets frowny-faced if you're diving unsealed, unbalanced pistons in 45F water. (Maybe with good reason - but actual statistics are hard to come by on free flows.)

I dived my MK 20 in 42 degree water and no freeflow. Any of those balanced pistons are flow through designs snd supposedly are the most prone to freezing. The MK2 is a flow by design so technically a little better against freeze up.
I think the whole freezing up thing is over blown for some of the upper temps people claim is problematic. I could see ice diving or water that is down in the thirties, but mid forties and up I don’t worry about it. Where I dive the water is between 47 and 53 degrees.
If you really want a reg that is impervious to freezing get a double hose. The whole diaphragm end with the spring is inside the fresh air side of the can. It never gets wet.

 

[Eric Sedletzky]

Upon reflection and since the main makers of piston Regs is Scuba pro and Atomic that in itself may be the answer.

Yes, I thought so too, but then I saw DGX has their version of a balanced piston and it’s more than their diaphragm model.
I’m curious about the DGX piston. I want to know the country of origin. I like the availability of parts.
I asked about this particular reg in another thread if anybody had it and their experience, but I got very little response.
I have the feeling the bulk of scubaboard members are not piston fans.

 

[lexvil]

Yes, I thought so too, but then I saw DGX has their version of a balanced piston and it’s more than their diaphragm model.
I’m curious about the DGX piston. I want to know the country of origin. I like the availability of parts.
I asked about this particular reg in another thread if anybody had it and their experience, but I got very little response.
I have the feeling the bulk of scubaboard members are not piston fans.

There are probably more MK 25’s out there than any other single model of regulator.

 

[BoltSnap]

I’m curious about the DGX piston. I want to know the country of origin. I like the availability of parts.

China I think. I know of at least one mfg. in China that has the exact copy of the first stage. I have their catalog.

 

[MrVegas]

China I think. I know of at least one mfg. in China that has the exact copy of the first stage. I have their catalog.

Taiwan, right, not mainland? Lots of regulators are made in Taiwan.

 

[halocline]

I don't think piston regs are more expensive by design, I just think that it happens that two of the most expensive brands, Scubapro and Atomic, feature balanced piston designs. Scubapro has dominated premium regulator sales for decades and their prices reflect that. Maybe that influences other companies to charge more for similar products.

I like my SP balanced piston regs because I know them well, I can service them easily, and they have proven themselves reliable to me in my own use. If I was as familiar with, say, Apeks diaphragm regs, I'd probably be just as comfortable using those.

In terms of bulletproof, proven design for 1st stages, the MK2 is great but not unique. The USD conshelf has been around just as long and is just as bulletproof. Both have been extremely influencial in 1st stage design over the years, spawning many variants and copies. Bottom line, both piston and diaphragm 1st stages can be decades-long workhorses.

 

[eelpout]

The Scubapro Mk2 Unbalanced 1st stage is the most popular rental regulator because if you are a Scubapro dealer because 1. you get a great deal of parts when you buy them for your rental set, 2. They are so simple to rebuild, 3. The parts can take abuse for years and still work. Just to pipe in about the unbalanced piston first stage, the reason they are not popular outside of shallow water and swimming pools is the fact that when your pressure in your tank drops the performance (Intermediate pressure ) drops too. So going deeper makes you use more gas and the performance decreases faster.

 

[bryankwatts]

I really wanted to initially buy a ScubaPro MK25 and then I saw a great video produced by RSingler that showed an MK25EVO used to provide air to 135 divers and I believe set a world record. If my memory is correct, RSingler mentioned that the MK19EVO and MK17EVO have very similar flow rates (less than 6.5% difference) and could service a similar number of divers. So, the flow is WAYYYY more than anyone actually needs and this took care of the question in my mind regarding flow of a piston reg vs a diaphragm reg. The next concern that I had was freezing and it looks like that really isn't much of an issue unless you are diving in water in the 30's F. So, in the end I purchased an MK17EVO diaphragm reg primarily because it is sealed and I don't end up getting as much crap in it, it cost a little less, and it doesn't appear to really have any major downsides.

 

[wetb4igetinthewater]

I always find it amusing when people claim "better" or "more reliable" without ANY data whatsoever.

The fact is when it comes to first stages, if the reg is properly serviced/tuned, no one is going to make the difference, though there are self-appointed experts who will claim they can feel the difference. Go and measure it, and compare the amount of force required to move the amount of gas that a person breaths during normal diving. I'm not interested in navy divers on bicycles underwater pumping furiously.

There is an S tax just as much as there is an H tax. Nothing wrong with that. PT Barnum was right.

 

[OrcasC205]

There is an S tax just as much as there is an H tax. Nothing wrong with that. PT Barnum was right.

But ScubaPro regs and Halcyon wings (and other gear) just look good, and everyone knows that looking good while diving is half the battle.