Gear-testing dive - flooded spg, should I have seen this coming?

[oreocookie]

Farallon was bought out by Oceanic in the mid 70's so that gauge has a few more than 30 years on it.

My mom bought it in '78, I think, and it hadn't been used since probably 1980 after having done maybe half the number of dives I have.

I have seen this quite a few times as a result of the regs being rinsed off without the dust cap on the first stage. Also we found that the water didn't ingress into the gauge until a few dives later.

I found similar things said when I did a quick search last night, which were disputed every time as it already has been here. If this were possible, I can tell you why it didn't happen in this case: The 1st stage it was attached to was seeing water for the first time, the hp hose it was attached to was seeing water for the first time, and the 1st stage and hp hose it was previously attached to hadn't seen water in 30+ years. I can't find any way to believe there has been that much water "hiding" inside the gauge for 30 years without evaporating/leaking out.

The idea of having a flooded SPG still connected to your first stage would give me an uneasy feeling.

Can you elaborate on that? If water can't go from the 1st stage to where it is in the gauge, why should I be concerned about it going the other way? or am I missing something here?

I figured a new gauge was in order, but I'll probably hang on to this one for possible future tinkering. I'm just glad I caught it now, not on my first dive on vacation where it probably would have stressed me out a bit.

 

[JahJahwarrior]

I have a two year old brass and glass gauge that is full of water and another that got salt water inside.

I need to replace but keep forgetting, and it hasn't killed me yet.

Sometimes they just fail. I have a much older plastic SPG in fine shape... So don't blame the dive shop and go buy a new one.

It's not because you got water in the first stage. That's silly. If water was leaking through the bourdon tube, air would be too

 

[g1138]

Oreo, I was under the impression that water could leak through the face of the SPG, into the inner workings, and then through the hose into your first stage.

 

[TSandM]

As already stated, this is a problem with the housing, not the internals of the gauge. The gauge will likely continue to work until either the pin corrodes and the needle won't spin any more, or until algae grows in the water and obscures the markings. (The latter was the fate of my last one to leak like this, when I was on Cozumel and had a great deal of trouble finding a simple spg to replace it with.) There is no possibility of water going back up the hose into the first stage, and this water did not come from a first stage leak or water in the first stage.

 

[Couv]

Your 1970ies Farallon SPG fared much better than mine. I had one exactly like that and the bourdon tube had a leak which caused the cover and face to blow out. Why didn't the relief plug blow? I don't think it had one. The front cover and face plate went whistling past my ear laughing as they ruined the dive minutes before I entered the water. Thinking back, I'm pretty sure the case had threads the cover screwed on to.

Heat the boot with a hair dryer and you'll have less problems removing it. Then tinker away-I suggest a strap wrench to remove the cover, fill with 90% alcohol, drain, then lube the gears and screw the cover back on. I cannot say if there was an o-ring seal or just a compression fit-the parts are still at Morrison Springs.

By the way, as others have pointed out, and made very obvious by the above, a leak from the bourdon tube into the case will cause a leak of gas-not water. If water gets into the bourdon tube, it's trapped.

I may have another one of those damn SPGs, I'll have a look when I have time.

 

[Couv]

....I may have another one of those damn SPGs, I'll have a look when I have time.

Well, I found an old Farallon SPG, but I it's a little different than the one that blew the front cover off. I think it's slightly smaller, has a blow out plug, and it does not have a screw on front cover.

Here are a few pictures of the Farallon. Compare it to the Dacor where you can clearly make out the front cover o-ring and threads visible on the side view. The last picture is just to show the parts. Note the o-rings that seal the front cover and the metal fitting going into the bottom of the case.

If you remove the boot from your SPG, check the case for cracks. If you don't find any, check the blow out plug if it has one. Next examine the hardware that screws into the case-make sure it hasn't come loose. This is one reason why you should always use two wrenches when installing or removing a hose on an spg.

Couv

 

[dumpsterDiver]

It is most likely cracked arounf the circular portion at the bottom of the guage, where the metal fitting is inserted.

 

[Couv]

....that's why two wrenches are necessary.

 

[mrfixitchapman]

Here's a possibility - if the gauge was a glycerine-filled unit it might look just like yours and be perfectly okay.

DC

 

[oreocookie]

couv, thanks for the info. I'll have to take a closer look at it when I have some time just for the sake of curiosity and understanding gear (in general) better. My thought right now (having not looked at the gauge since monday, when it was still as full of water as in the pic) is if it took almost 3 ata of pressure to get the water in there, then will the water come back out by itself? My guess is if the air bubbled out and was replaced by water, then no or at least very slowly, but if the air got compressed and water took up the extra space then the "extra" air might be just as likely to seep out as the water.

mrfixit, interesting suggestion. While I doubt that's the case here because I don't remember there being any obvious liquid in the gauge before diving with it (and if there was, it must have leaked out in order to look the way it now does, which probably would not be a good thing) how would you know for sure if it is glycerin-filled or not?