Only a goose would wear a belt AND suspenders... oh wait!*wags finger and frowns judgingly* You missed the depth gauge backup thread. It directly applies.![]()

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Only a goose would wear a belt AND suspenders... oh wait!*wags finger and frowns judgingly* You missed the depth gauge backup thread. It directly applies.![]()
I have them slightly depress the purge on the second stage as well. That reduces the shock on the whole system. When they hear the hiss they gently release the purge and finish opening the tank with a 1/4 turn back (except on doubles or a rebreather).Equally I tell them to just crack the cylinder open at first
Two instances I've seen, a Marshall Islander/Bikini Atoll Dive Guide and a CCR Diver at Truk -both absentmindedly cranking open -instant full impulse on- their tank valves.
The tanks were Oxygen filled, and the effect for the CCR Diver was much more catastrophic than an exploding SPG face gauge and a smoking 1st Stage: An out-of-control 1st Stage "O2 welder"; burnt-up wing & scorched scrubber canister, and extensive 2nd degree burns up his left arm with a small third degree patch by the wrist.
I look into the lens so the blowout plug is away from my face. All SPGs "should" have a blowout plug, which "could" become a small projectile.
I have seen industrial gage faces blow from work hardened Bourdon tubes due to vibration. More accurately, I heard it, turned around, saw what was left, and shut a stop valve. The bourdon tube cracked close to the solder joint.
A friend with a large regulator service business strongly recommends this. Occasionally opening the tank valve too quickly can cause damage to something inside a piston regulator first stageI have them slightly depress the purge on the second stage as well. That reduces the shock on the whole system. When they hear the hiss they gently release the purge and finish opening the tank with a 1/4 turn back (except on doubles or a rebreather).