Metal or Poly 2nd stage?

[Nemrod]

Wet breathing regulators indicate a problem, like a leaking exhaust valve, perforated or partially unseated diaphragm, mouthpiece not secured properly, cracked plastic second stage body, etc. A moist breathing regulator is due to moisture in your breath condensing on the metal case/parts and then being essentially recycled to the next breath. Wet = Bad, Moist = Good.

N

 

[Seefourdc]

Isn't the only thing that effects the moisture of the breath the barrel makeup? As in a plastic outer shell or metal outer shell don't effect it because that's not where the moisture is occurring, it's the barrel itself that's condensating and adding moisture?

 

[elan]

It's occurring on the metal elements wherever they are. Be it a barrel or case. I do notice a difference between plastic, metal barrel - plastic case and all metal regs.

Isn't the only thing that effects the moisture of the breath the barrel makeup? As in a plastic outer shell or metal outer shell don't effect it because that's not where the moisture is occurring, it's the barrel itself that's condensating and adding moisture?

 

[Nemrod]

Isn't the only thing that effects the moisture of the breath the barrel makeup? As in a plastic outer shell or metal outer shell don't effect it because that's not where the moisture is occurring, it's the barrel itself that's condensating and adding moisture?

No, it occurs on all metal parts exposed to the air flow.

N

 

[ams511]

Isn't the only thing that effects the moisture of the breath the barrel makeup? As in a plastic outer shell or metal outer shell don't effect it because that's not where the moisture is occurring, it's the barrel itself that's condensating and adding moisture?

As Nemrod said. Remember not all regulators have an air barrel. For example the Sherwood Oasis uses a downstream valve but adds metal fins to reduce dry mouth.

 

[KeithG]

Can anyone explain the science behind the (mis?) belief that metal is moister than plastic?

Condensation will occur on anything that is colder than the surrounding air. It happens on my beer cans, the glass windows in my house and my plastic Gatorade bottle. So it does not appear to me to be dependent upon the material in question.

Am I missing something obvious?

 

[elan]

Can anyone explain the science behind the (mis?) belief that metal is moister than plastic?

Condensation will occur on anything that is colder than the surrounding air. It happens on my beer cans, the glass windows in my house and my plastic Gatorade bottle. So it does not appear to me to be dependent upon the material in question.

Am I missing something obvious?

Yes, metal transfers heat way better than plastic. So the cold expanding air cools down the metal parts faster and they are colder then plastic parts. The colder they are the faster condensation occurs thus trapping moisture on the walls instead of venting it outside.

 

[KeithG]

Yes, metal transfers heat way better than plastic. So the cold expanding air cools down the metal parts faster and they are colder then plastic parts. The colder they are the faster condensation occurs thus trapping moisture on the walls instead of venting it outside.

I am assuming that the effect of the surrounding water will fix the temperature of both the metal and plastic. Any effect from the breathing gas will be neglible compared to the ambient water. A free flow situation could have some measurable effect on a very small area, but normal breathing does not create much of a gas flow. I am fairly certain that my regulator stays at ambient water temp, regardless of its material composition.

 

[elan]

Unless you dive in 36.6C water the temperature inside the metal case will be lower as the heat from the exhaled air will be tranfered to the ambient water faster so the case will be cooler. Expanding gas lowers the temperature even further. Plastic isolates the heat better so the surface temp of the plastic inside the case will be higher.

I am assuming that the effect of the surrounding water will fix the temperature of both the metal and plastic. Any effect from the breathing gas will be neglible compared to the ambient water. A free flow situation could have some measurable effect on a very small area, but normal breathing does not create much of a gas flow. I am fairly certain that my regulator stays at ambient water temp, regardless of its material composition.

 

[ams511]

Can anyone explain the science behind the (mis?) belief that metal is moister than plastic?

Condensation will occur on anything that is colder than the surrounding air. It happens on my beer cans, the glass windows in my house and my plastic Gatorade bottle. So it does not appear to me to be dependent upon the material in question.

Am I missing something obvious?

Do you get condensation on the walls inside your house in the winter time? It is cold outside and warm inside, correct?