Assembling an SPG?

[g1138]

Hey all,
So I've decided to wrist mount my computer. It's a Sherwood Insight which originally came in a compact console.

Link w/ Pics (See "Front View" Pic)

I've decided to reuse the SPG inside the console boot.
In order to take it out I have to undo a few hoses.

My question is. How many parts do I have to worry about, falling out of my SPG.
So far I've considered 3 components :
1) Hose
2) SPG Spool
3) SPG gauge

Is there any special instructions or considerations I should be worried about when I "take apart" my SPG and put it back together?
ie. any special orientation the spool has to be in etc

Thanks in advance!

 

[g1138]

Follow up question:
If I need to relube the spool oring, should I use O2 clean lube? I'm nitrox certified so there's always the chance that I'll be using less than 40% nitrox with this SPG.

 

[Bubbletrubble]

Is there any special instructions or considerations I should be worried about when I "take apart" my SPG and put it back together?
ie. any special orientation the spool has to be in etc

Use a couple of wrenches when you disassemble/reassemble the HP hose and SPG.
The HP spool/stem goes in-between the hose and the SPG.
Inspect the spool for any cracks. Clean it up with some vinegar and then rinse well with water. Put some new -003 o-rings on it and lube it up well.
Honestly, you can use silicone lube, Christolube, or Tribolube 71. Your choice. Just use a generous helping of it.

Purchase an extra HP spool (same variety that you use) and stick it in your save-a-dive kit.

It's all pretty straightforward.

 

[g1138]

Thanks Bubbletrubble!

What's the purpose of cleaning the stem? My SPG has never been taken apart before, this will be the first time. Could I skip the O-ring replacement and washing?

Also under what conditions would I need to replace just the spool during a dive trip?

 

[Bubbletrubble]

What's the purpose of cleaning the stem? My SPG has never been taken apart before, this will be the first time. Could I skip the O-ring replacement and washing?

The purpose of cleaning the HP spool is to prevent corrosion from setting in. That might inhibit rotation of the gauge while pressurized and would eventually lead to cracking/breaking of the spool. If the HP spool and the o-rings look good, I suppose you could just re-lube the o-rings and reassemble.

If your SPG is new (under a year old?), I doubt there's any corrosion on the HP spool yet.

Also under what conditions would I need to replace just the spool during a dive trip?

I would replace the HP spool if, when I pressurized my reg during pre-dive checks (or any other time really), I detected hissing coming from the HP hose/SPG junction...or if I noticed "champagne bubbles" emanating from the HP hose/SPG junction underwater. HP spool failure is pretty obvious.

If the HP spool is sheared into two pieces (or even if it stays intact), you may have to gently coax out the piece that's stuck in the SPG. Needle-nose pliers can be helpful in this case. You just don't want to damage the SPG.

On a side note, lots of the SPGs that come in stock consoles have a plastic face/housing. This makes them very lightweight, but, if they are removed from the protective console, it also makes them more susceptible to damage.

 

[g1138]

Gotcha. My SPG is 1 year old and just came out of it's annual service. The spool was covered in white grease when I took it apart.
It's all back together now minus the boot.

However when I pressurize the entire reg the SPG is hard to swivel. It swivel's fine when it's not pressurized.
Should I put more more grease on the spool?

 

[Bubbletrubble]

Gotcha. My SPG is 1 year old and just came out of it's annual service. The spool was covered in white grease when I took it apart.
It's all back together now minus the boot.

However when I pressurize the entire reg the SPG is hard to swivel. It swivel's fine when it's not pressurized.
Should I put more more grease on the spool?

They always swivel fine when not pressurized...unless there's some major corrosion present.

Over the years, I've ended up using more and more lube on the HP spool o-rings and even a little bit on the spool itself. It's worked for me. YMMV.

It sounds like the pressurized SPG swiveled OK before you started messing with it. Is that true?

Yeah, you may just have to "generously" apply more lube.

FWIW, I once purchased a second-hand SPG that didn't swivel very nicely. I found that it required some cleaning of the area inside the SPG that contacts the HP spool. After a cleaning, it swiveled nicely -- both unpressurized and pressurized.

 

[redacted]

While that is one of those things where the more lube the better, it is to protect against corrosion and not to help it swivel. It is probably just fine and you are just seeing what happens when 3000 psi is applied to the hose metal to metal connection. As long as it is not leaking, you should have nothing to worry about.

 

[g1138]

I re-lubed the spool and lubed the swivel on the hose a bit, and now it's back up to what it used to be. Still not swiveling great, but that's only because I never rinsed behind the hose protector when I first got it. (I actually had no idea there was even one there)

You're probably right though awap, more lube won't fix the issue entirely. I talked to friend of mine who has the same problem. He said his swivels fine underwater but above water it's a bit more stiff.

For now I'm happy, can't wait to try it out in the water. I'll just bide my time with some caveline and a bolt snap for now.

Thanks, both of you!