View Full Version : Another Can of Worms
Been meaning to start the ball rolling on this one for ages!
Why oh Why do some divers feel the need to turn on their air and blast it at their first stage after they have completed their dive and have disconnected them?? They have been connected under pressure with nothing getting at them since they put them on, what do they think they are blowing out of them!
During my padi training i was told it was to remove residual water. Now i use a cloth to wipe any water of the inlet filter rather than force it into the stage with air.
Mad Major
I was told during open water training it was to dry off the rubber blank on A-clamp first stages, to prevent any water getting in the first stage.
If they're blowing air at the first stage then all they're doing is blowing any water droplets that may have settled around the inlet orifice into the first stage. Over time this will mean the reg will need serviced earlier.
However, I think why some people do this is because they have been confused by the practice of blow drying the sealing face of a dust cap on an a-clamp reg. Which is how I was taught and is entirely OK if you have a dust cap that goes with you on the dive.
John Bantin of Diver magazine has a bit of a bugbear about people using their cylinders to blow dry dust caps and suggests that people 'use a dry towel instead'.
Aye right John, plenty of dry towels kicking around on a RIB in the Clyde:rolleyes:
However, I think why some people do this is because they have been confused by the practice of blow drying the sealing face of a dust cap on an a-clamp reg. Which is how I was taught and is entirely OK if you have a dust cap that goes with you on the dive.
Yep. I would agree with that. I know that's why I do it (note to self, stop doing it :o )
If one covers the first stage hole with ones thumb as one does it no water will enter the stage, at least thats what i do.
I always give my tank a quick blast off just to get rid of the water around the valve and to clear the water in the rubber cap.
Scuba-Doh!
02-09-07, 00:16
Rubber cover clearing for me, though on a din-type reg :o
DIN for me too, have seen the cut up Pony at Aquatron that was not given a quick blast off after each dive, rusted to buggery after a year !!. Quick littlle blast to get rid of any water around the valve can't do any harm
A lot of regs these days have sealed first stages. That’s what the info on my XTX said. In theory nothing can get past the seal ball into the stage unless its under pressure.
I do the air blast clearance out of old habit. The info suggests I should be ok rinsing the reg in fresh water as is. I could even be overcoming the ball spring device by doing the air blast. Any consensus on those with sealed first stage.
DIN for me too, have seen the cut up Pony at Aquatron that was not given a quick blast off after each dive, rusted to buggery after a year !!. Quick littlle blast to get rid of any water around the valve can't do any harm
DIN set of regs, 6 years old, not blasted after each dive, no rust and serviced each year.
Lizardland
02-09-07, 13:16
If you have to dry the cap off then why take it with you? Leave it in a bag, it stays dry.
Unless Apeks have changed their first stage design then water will get in if you haven't capped the inlet even if not under pressure. The dry sealed system is how the ambient water pressure is transmitted to the internal workings of the 1st stage, it's not AFAIK to do with the inlet. On older (Poseidon) or cheaper (Scubapro Mk2) 1st stages water is allowed to enter a chamber and the pressure acts on either a piston or diaphragm which transmits it into the valve's guts. On Apeks and other 1st stages the entire valve is sealed and pressure is transmitted via a diaphragm on the exterior of the valve. It's more to do with improving performance in cold water (unsealed regs have a bigger chance of freezing) than preventing corrosion. You won't get any corrosion to speak of in an Apeks reg (except maybe on a spring occasionally), the really problem on the inside is getting salt crystals building up. If a service tech ever tells you that your 1st stage was corroded then ask to see it.
Cheers,
Stuart
Errr it's the inside of the tanks thats rusty not a set of regs.
DIN set of regs, 6 years old, not blasted after each dive, no rust and serviced each year.
It was a tank i was talking about, not a set of regs
It was a tank i was talking about, not a set of regs
Oh right - well my tanks appear to be okay too, although they are not as old.
I blast the air out of the dust cap only.
Any water, particularly sea water, in the first stage is a no no.
Dry towels on a Scottish dive site?
Never seen this being taught, have though shown people to dry of the dust cap with a bit of a blast. Sometimes gets wet in your hands, from the rain, whatever. All the teaching i have been involved in has never shown to blast the regs with air. On the other hand everything we used was din.