Dynamic vs Static O-Rings - Scuba Tech Tips: S09E09

[@dalerichardson8842]

Love your sense of honour Alec! The Port Plug thing made me laugh ! I am really enjoying your films , I watch 2 or 3 each night and will be sad when I am all up to date and will have to wait for the next one. I have learnt so much so thank you ! Best wishes Dale

[@AlecPeirceScuba_SeaHunter]

Awesome! Thank you! More coming including a few Vintage Scuba. Thanks for watching and the kind feedback. A

[@bristol8920]

Thanks Alec always learn something with your Tech Tips........................

[@AlecPeirceScuba_SeaHunter]

Thanks for watching bristol. Good to hear from you. Alec

[@fldallyb]

I really enjoy your videos, please keep up the good work.

[@pollux901]

Great video. Thanks!

[@AlecPeirceScuba_SeaHunter]

Your welcome. Lots more to learn from this old guy. A

[@Vasilis_Chatzis]

Hi Alec! The Auto Closure Divice (ACD) in regulator is good? And how it works ? Moreover can I wash regulator with ACD without dust cap ?

[@AlecPeirceScuba_SeaHunter]

No!! I mean, don't wash without a dust cap even if you have an ACD. I just did a Tech Tip today about these devices and what they're all about. Watch for it soon. Alec

[@jonathandcraig]

Alec, thanks for this video! Do you find that static o-rings are less prone to failure during normal use than dynamic o-rings? Would you approach either type of o-ring differently when it comes time to have a yearly service? I’m specifically wondering about the o-rings in the intermediate pressure area of a regulator, such as on a 2nd-stage regulator hose, for example (the end inserted into the first stage). Would that o-ring typically be replaced as frequently as the 1st-stage piston’s dynamic o-ring?

[@AlecPeirceScuba_SeaHunter]

When a service is done, the tech has to follow the makers requirements, which generally mean ALL o-rings are replaced in the 1st & 2nd stages. The cost of a o-ring is very small compared to a failure while diving. A

[@pricediver]

Very useful information !! How tight should I put my port plug in ?

[@AlecPeirceScuba_SeaHunter]

The port plug, like the hoses, seals with an O-Ring so it doesn't have to be tight to make the seal. It only needs to be tight enough to keep it from falling out. There is no specified torque value, or if there is, it's different from one brand to another. So generally I suggest you tighten it by hand as far as possible. Notice when it gets hard to turn. That's when the O-Ring has contacted the metal body. Now turn it with a 1/2" or 9/16" wrench about another 1/8 to 1/4 turn. You should see the plug has just contacted the body. There is no discernible crack. To check or for practice, try to loosen it with the wrench. It should NOT take much effort - less than opening a fresh jar of jam but more than tuning a radio. Hope this helps. Alec

[@chrisfischer7918]

Hi Alec. Excellent videos. Should tank and SPG o-rings be replaced every year?

[@AlecPeirceScuba_SeaHunter]

When a tank has its annual Visual inspection, the tank O-ring should be replaced. It's a buck and holds 3000 psi so don't go cheap and re-use it.

[@anhonestman1234]

Hello Alec. When replacing orings, do you use silicone on the new oring?

[@AlecPeirceScuba_SeaHunter]

Only dynamic o-rings MAY need lub. Search my videos for a video on dynamic vs static. I say MAY as it is up the to manufacture spec and which o-ring you're talking about. If it's something only a Service Pro should do, no worries, they will follow specs. If it's a diver changeable o-ring, like tank valve, hose end then no lub. A

[@anhonestman1234]

@@AlecPeirceScuba_SeaHunter thanks

[@jeffworst9939]

Hi Alec. I'm late to this party but is there such a thing as a "dynamic o-ring"? IOW, are o-rings made for use in a dynamic application (e.g., on a 1st stage piston) different from an o-ring made for a static application (e.g., to seal a light)?

[@AlecPeirceScuba_SeaHunter]

The best example of a dynamic O-ring is in a piston reg. The piston moves up and down extremely fast to keep the IP pressure constant after every breath. Static O-rings don't move as in a tank valve. I plan to do more videos on the amazing room of o-rings so keep watching.

[@jeffworst9939]

@@AlecPeirceScuba_SeaHunter I think my question wasn't clear enough. Are o-rings used in a dynamic application (e.g., piston reg. like you described) different, in terms of how they're made, from o-rings used in a static application (e.g., dive light)? IOW, are some o-rings made specifically for dynamic applications so then can endure the constant wear better than other o-rings?

[@joek6791]

@@jeffworst9939 The O-rings are the same, they do come in different materials, buna, Viton for 02 service and other more exotic materials. They also come in different hardness Shore ratings. For example the O-ring on the tank valve to tank interface is a 90 while other common O-rings maybe 60. For most applications buna are fine. If you buy o-rings from a scuba shop you are being ripped off. You can buy them in bulk from the manufacture for a couple of cents. I rebuild all of my own regs since I am a sump diver and have bought them directly for 30 years. Store them in class jars and under cool dark conditions and they will last for more than 20 years. The above is the cliff notes version.

[@Dive_Me_Crazy]

If you have a port plug can you also get a starboard plug? Do you need to check you ports before you leave port.... and can you do it starboard, or do you have to be on the port side? Love it - very dynamic video

[@AlecPeirceScuba_SeaHunter]

What can I say Eric - any port in a storm!! Take care. Alec

[@scubasteveandunderwaterroc3547]

Very interesting thanks for another great video

[@AlecPeirceScuba_SeaHunter]

Thank you SS&URC! Alec

[@markstengel7680]

Hi Alec, Watched this episode and enjoyed your presentation of O Rings.

[@AlecPeirceScuba_SeaHunter]

Hope you picked up something Mark. Take care. Alec

[@2shizz]

Is oil used to lubricate the piston?

[@AlecPeirceScuba_SeaHunter]

Only the lubricate specified by the manufacturer can be used, no substitutes. Generally on re-assembly you lubricate the bore with a special Christo-Lube compound. Any other product risks excessive wear from contaminates or affecting the breathing air quality. A certified service tech may let you watch next time your is in to show you how it is done (note the manuals, tools and training to do it right).

[@2shizz]

@@AlecPeirceScuba_SeaHunter thank you Alec. Your video was extremely informative and helpful

[@sikaatbleeh]

Hi Alex, is this correct that Scubapro MK25 or MK25evo is an unsealed first stage, yet the sea water is not touching the piston due to the design? Thank you

[@AlecPeirceScuba_SeaHunter]

Not exactly. The EVO (simply short for Evolution) design itself helps to lessen the likelihood of freezing. It incorporates several features to that end such as a heat sink around the 1st cap and the 2nd hose swivel plus much larger holes in the 1st to stop jamming of ice particles and also enhance rinsing. Now they have XTIS (Extended Thermal Insulating System) which adds a few more features with the same aim. They include a plastic coating on the 1st spring to eliminate ice formation and plastic insulating washers to keep metal to metal contact to a minimum. Apparently, in tests this practically eliminated ice sticking to the parts of the 1st. So water still enters the 1st so the reg can function correctly but the water doesn't touch metal. Note that no regulator design can eliminate the possibility of freezing since the formation of ice in a 1st stage is a result of water in the air combined with the adiabatic temperature drop from the pressure drop that is part of the reg function. Nothing mechanical can eliminate those factors, only reduce them. Here's a great Scubapro PDF file that explains this in detail plus a lot more: file:///C:/Users/Alec/Downloads/MK25%20EVO%20System_Presentation_ENG.pdf Take care. Alec

[@alaind831]

maybe the lesson is that some o-ring need to be changed frequently than others that may almost never need a change (o-port rings)...

[@AlecPeirceScuba_SeaHunter]

Good point Alain. Dynamic O-Rings are always included in a service kit and should always be changed. Static too. They don't move so can just as easily be destroyed by being squashed repeatedly in the same manner. A good example is the tank neck O-Ring. It's a nice, shiny, round O-Ring when installed. One year later at visual time, it's like a flat rubber washer! Many service people don't change all of the O-rings in the kits. They think they can look at an O-Ring and determine if it's OK or NOT OK. Nope! Change them all. There's no such thing as a one or two-year-old O-Ring that's OK! And they cost like 15 cents each!!!!!!!!!!! Take care. Alec

[@musthaghussain2696]

port plugs are made from brass and chrome plated not steel