Be a fan of ScubaBoard.com

Welcome to ScubaBoard, an online scuba diving forum community where you can join over 205,000 divers from around the world discussing all things related to Scuba Diving. To gain full access to ScubaBoard (and make this large box go away) you must register for a free account. As a registered member you will be able to:

  • Participate in over 500 dive topic forums and browse from over 5,500,000 posts.
  • Communicate privately with other divers from around the world.
  • Post your own photos or view from well over 100,000 user submitted images.
  • Gain access to our free classifieds marketplace to buy, sell and trade gear, travel and services.
  • Use the calendar to organize your events and enroll in other members' events.
All this and much more is available to you absolutely free when you register for an account, so sign up today!

If you have any problems with the registration process or your account login, please contact the ScubaBoard Support Team.
Page 1 of 2 12 LastLast
Results 1 to 10 of 12


  1. #1
    Registered


    Has not set a "status"
     

    JD.Gattis's Avatar
    Join Date
    Sep 2004
    Posts
    24

    Piston vs. Balanced Diaphragm

    Wich is the best to get? and why.

  2. #2
    ScubaBoard Enthusiast


    Has not set a "status"
     

    MechDiver's Avatar
    Join Date
    Oct 2002
    Location
    Washington State
    Posts
    2,384
    Quote Originally Posted by JD.Gattis
    Wich is the best to get? and why.
    There is no best. They each do a job, and each does it well.
    There are also hundreds of posts here already on the pros and cons of each that you can access using the search button.

    MD

  3. #3
    ScubaBoard Enthusiast


    Has not set a "status"
     

    Quarrior's Avatar
    Join Date
    Feb 2004
    Location
    Boise ID
    Posts
    1,961
    Dives
    100 - 199
    Photos
    21
    Quote Originally Posted by JD.Gattis
    Wich is the best to get? and why.
    Really depends on the diving environment you intend to dive in.

    Pistons are open to the elements and prone freeze up in cold water, below 45F.

    Diaphram regs tend to be environmentally sealed (not all are mind you) and tend to work better in cold water for that reason.

    As for which works better. Everyone has their own belief. Some say piston is better because it has direct access to the water pressure and therefore adjusts more accurately. Others say that is a load of bunk.

    Personally, I dive an environmentally sealed diaphram because I dive in cold murky water.
    "A veteran - whether active duty, retired, national guard, or reserve - is someone who, at one point in his or her life, wrote a blank check made payable to The 'United States of America', for an amount of 'up to and including my life.'" (Author unknown)


  4. #4
    ScubaBoard Contributor


    Has not set a "status"
     

    scubapro50's Avatar
    Join Date
    Aug 2004
    Location
    Port Arthur Texas
    Posts
    917
    Dives
    1,000 - 2,499

    Rolling my eyes

    warm water diving a piston is great .... take a look at he classic Scubapro MK5 ... it's one of the most enduring designs ever. A piston just seems to hold up better than a diaphram because there are a lot less parts to wearout or break. I own a MK10 and love it. My wife has a Dacor Pacer 360 and have had the first stage worked on twice due to problems in last 4 years. That's one reason I hate to see Dacor drop their "lifetime warranty" support of it (see thread "dumped on by diving companies again".

  5. #5
    Public Safety Diver


    Has not set a "status"
     

    Gary D.'s Avatar
    Join Date
    Feb 2002
    Location
    Post Falls, Idaho
    Posts
    4,365
    Dives
    I'm a Fish!
    Photos
    157
    Quote Originally Posted by Quarrior
    Really depends on the diving environment you intend to dive in.

    Pistons are open to the elements and prone freeze up in cold water, below 45F.

    Diaphram regs tend to be environmentally sealed (not all are mind you) and tend to work better in cold water for that reason.
    Not all in either case you just stated.

    I also dive a lot of nasty water and that is one of the reasons I dive a dry bleed piston.

    Gary D.
    What ever you do in life do it well and do it safe.

  6. #6
    Divemaster
    Badge


    Protect your freedom, defeat
    Obama!
     

    Randy43068's Avatar
    Join Date
    Jun 2003
    Location
    Columbus, Ohio
    Posts
    6,057
    Dives
    100 - 199
    Photos
    7

    Conshelf

    I have an older Conshelf SE2 but don't know if it's a piston or diaphram. Do you know which it is?

    Thanks,

    Randy


    Quote Originally Posted by Quarrior
    Really depends on the diving environment you intend to dive in.

    Pistons are open to the elements and prone freeze up in cold water, below 45F.

    Diaphram regs tend to be environmentally sealed (not all are mind you) and tend to work better in cold water for that reason.

    As for which works better. Everyone has their own belief. Some say piston is better because it has direct access to the water pressure and therefore adjusts more accurately. Others say that is a load of bunk.

    Personally, I dive an environmentally sealed diaphram because I dive in cold murky water.

  7. #7
    ScubaBoard Enthusiast


    Has not set a "status"
     

    Quarrior's Avatar
    Join Date
    Feb 2004
    Location
    Boise ID
    Posts
    1,961
    Dives
    100 - 199
    Photos
    21
    Quote Originally Posted by Randy43086
    I have an older Conshelf SE2 but don't know if it's a piston or diaphram. Do you know which it is?

    Thanks,

    Randy
    To my knowledge and there are more knowledgeable people than me here. The easiest way to tell is to look at the first stage. If it has holes in the sides, other than the ports, it is a piston reg.
    "A veteran - whether active duty, retired, national guard, or reserve - is someone who, at one point in his or her life, wrote a blank check made payable to The 'United States of America', for an amount of 'up to and including my life.'" (Author unknown)


  8. #8
    ScubaBoard Enthusiast


    Has not set a "status"
     

    garyfotodiver's Avatar
    Join Date
    Mar 2004
    Location
    Chicago, but dive in FL. Not true anymore, as I did my first Lake Michigan dive.
    Posts
    1,308
    Dives
    200 - 499
    Quote Originally Posted by Randy43086
    I have an older Conshelf SE2 but don't know if it's a piston or diaphram. Do you know which it is?

    Thanks,

    Randy
    Conshelfs are diaphragm 1st stages. I own own three, one from 1969, 1980, and 1995. All very similar.
    Gary
    NASDS Scuba Diver (1970), SSI Diver Stress & Rescue (2004), SSI AOW (2005), SSI Master Diver (2011)
    It is the mark of an educated mind to be able to entertain a thought without accepting it.
    Aristotle; Greek critic, philosopher, physicist, & zoologist (384 BCE - 322 BCE)

  9. #9
    ScubaBoard Contributor


    Has not set a "status"
     

    Join Date
    Jun 2003
    Location
    Ohio
    Posts
    779
    Dives
    1,000 - 2,499
    A balanced diaphragm reg cannot provide the massive gas flow that a large bore balanced piston can provide. The air passages are just too small in comparison to the orifice found in a balanced piston. That being said...A second stage can only deliver so much gas, and the top diaprhragm designs on the market can easily meet the needs of two divers at depths in excess of 150'. How many times do you need more gas than that?

    Personally, I own diaphragm, unbalanced piston, and balanced piston designs. I tend to use the diaphragm varities for almost all my dives due to the bulk of my dives being in colder water.

    Greg

  10. #10
    ScubaBoard Enthusiast


    Has not set a "status"
     

    rescuediver009's Avatar
    Join Date
    Aug 2003
    Location
    Southern, Ontario
    Posts
    1,369
    Please tell me that you did a search on this.....
    I am not a veteran but I have seen 3 separate threads posting the exact same question.

    No one is bette than the other though. You have to also realize that there are separate types of each:
    Pistons: unbalanced, balanced sealed, balance flow through, and flow through.
    Diaphragm: Balanced, Overbalanced, unbalanced upstream.

    Each performs differently and one better in separate conditions. And truth be told with a blindfold on sometimes you cannot even tell the difference. I think that pistons are (not better) more common to recreational divers as they usually have a lower cracking pressure and this is more pleasant to learn to breath on. Diaphragm regs are more popular in technical diving than they are in rec diving. They can hold up to a litle more, have alot less o-rings and moving parts.

    AS ALWAYS THOUGH THERE ARE EXCEPTIONS TO EVERY RULE.
    TDI Adv. Nitrox & Deco
    PADI DM,
    EFR/DAN O2 Instructor
    Apeks, Sherwood, Aqualung & USD Technician

Page 1 of 2 12 LastLast

Similar Threads

  1. diaphragm or piston 1st stage?
    By watchoutheyspit in forum Regulators
    Replies: 3
    Last Post: April 2nd, 2005, 03:41 PM
  2. Piston vs. Diaphragm
    By cwtan in forum Regulators
    Replies: 64
    Last Post: November 19th, 2003, 09:17 AM
  3. Piston Diaphragm ??? What
    By alex6 in forum General Scuba Equipment Discussions
    Replies: 7
    Last Post: July 8th, 2003, 07:44 AM
  4. balanced diaphragm vs. balanced piston
    By DivingDoc in forum Regulators
    Replies: 65
    Last Post: November 22nd, 2002, 07:10 PM
  5. Replies: 11
    Last Post: July 21st, 2002, 07:12 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •