Exploding SPG gauge faces?

[bergersau]

I had a SPG blow right off the end of the Hp hose last year. The swage just near the spool let go just after cracking the valve open and the entire 2" brass SPG was fired off the hose into the deck of the boat. Hose was only a year old at the time too.
I was very glad the hose was pointed down at the deck and not towards another diver when that happened.

 

[Dan]

I had a SPG blow right off the end of the Hp hose last year. The swage just near the spool let go just after cracking the valve open and the entire 2" brass SPG was fired off the hose into the deck of the boat. Hose was only a year old at the time too.
I was very glad the hose was pointed down at the deck and not towards another diver when that happened.

Mine too, pointing down most of the time

It's 4 years old & still doing fine (knock on wood). The reading still matches with that of my dive computer to within +/- 50 psi from 500 to 3200 psig and no battery required.

 

[Scared Silly]

Close but no Cigar ....but as would be expected from you ---you are on the right tract

But for many years there as only one SPG - the Mar Mac manufactured up in northern California

SDM

Here ya go Sam!! The MarMac SeAir

 

[Boaty McBoatface]

Maybe they can engineer AI computer screens to explode once every 10,000 dives.

Samsung has some experience in this area...

 

[Sam Miller III]

@Scared Silley
Thanks for displaying your SPG--fortunately for you it is a late model Mar Mac and not the pioneering model of 1950s

SDM

 

[Saniflush]

Will my camo bib overalls suffice for a good guffaw???

I can one up you. I was sporting the redneck romper on the Aqua Cat. (bib overall cutoffs) They were quite the conversation piece. You can't hide money.

 

[Kharon]

Had a button gauge shoot it's lens at high velocity when getting my pony filled. They did the fill at high speed and probably overfilled the tank. The SPG lens would have put a hole in anyone in front of it. Since then I fill my ponies myself from a tank.

 

[g1138]

Plastic face gauges seem more possible for a faceplate blowout than glass. Glass is held by a very sturdy brass rim. Plastic is often not and just inset and sealed with an oring.

There should not be any pressure behind the faceplate normally unless the bourbon tube is compromised.
Even then, after every Button Gauge blowout I've seen, none continued to leak after the initial blowout. I don't know why though.

I've taken apart both glass/brass & plastic face spgs and it reiterates this belief for me.
I don't think it will maim you in the face, but I have full confidence it will make you lose your eye if it hits right.

Universal precaution is a nice thing for this situation, so I still teach it.

 

[TMHeimer]

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).

I revived this thread because someone (on another thread?) said that pressing the purge slightly when turning Air on does nothing (now, I'm talking simple one AL80 tank here). He said to try it and notice the SPG needle goes up just as fast whether you purge or not. Today I happened by chance to run into the CD who taught me that years ago and he said what you say--it's less of a shock to the whole system. He said "notice the SPG won't jump so fast if you purge, and the needle will rise slower". I THINK I noticed a difference in the "jump", but not really in the needle rising. What do you think?

Oh, Pete, I wear both belt AND suspenders to hold it up--no worries about ever having a belt slip off my "male" hips. No tightening a belt enough to bust my gut. This is unusual???

 

[Sam Miller III]

What is a CD?

It all began with the introduction of the Mar Mac SPG in the 1950s
Certainly SOME ONE can guess why it was recommended that the SPG was turned away or shielded by a cupped hand

The Mar Mac had three distinct problems associated with it

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SDM