Regs\octo\spg assembly.

[Adrian Hutchison]

Hi,
New member, 1st post etc, so apologies if this one's been answered before (or is just a silly question!). I've just received the component parts of my first regs setup: Scubapro mk25 1st stage, 2 x R390 second stages, SP twin spg and a BCD hose.
All have come separate. I'm pretty engineering minded and understand which ports are which so don't mind popping it all together. But is there any specific type of grease i should use for the O-rings? and do the hoses need to be attached to any specific torque settings? or will just spanner tight be ok?
Thanks,
Adrian

[ChristianG]

New member, 1st post etc, so apologies if this one's been answered before (or is just a silly question!). I've just received the component parts of my first regs setup: Scubapro mk25 1st stage, 2 x R390 second stages, SP twin spg and a BCD hose.
All have come separate. I'm pretty engineering minded and understand which ports are which so don't mind popping it all together. But is there any specific type of grease i should use for the O-rings? and do the hoses need to be attached to any specific torque settings? or will just spanner tight be ok?
Welcome aboard Adrian, and whilst it's all been said before it never hurts to be repeated sometimes. Besides, "silly" describes the question never asked. :)

Let's talk O Rings first. You are here describing what is generally termed "sedentary" O Rings, IOW they have no particular need to move, as against the O Ring sealing the on/off switch on a torch for example.
Although some might disagree with me I consider that sedentary ones should not be greased, for that very reason. Grease is only required if the O Ring needs to work in some way, it plays no part in the integrity of the system, furthermore grease attracts dirt, a clean O Ring repels it. All you really need to do is ensure that the surfaces are clean, and I do mean clean, when assembling it, a misplaced hair can often be sudden death to an O Ring. Now that applies to the O Rings on your first stage, but your 2nd stages and your combo swivel don't they? Well, yes, but I for one consider that clean O Rings on a purely rotational device are better than the dubious advantages of grease - and the dirt it inevitably attracts.

You have probably already found that pressurised kit locks everything together, such that only brute force (to be avoided at all costs) will bring it asunder unless you have first depressurised the kit. Thus a simple nip, just enough to stop the screw mechanism (which also plays absolutely no part in the integrity of the system) being accidentally unlocked by errant fingers, is perfectly sufficient when screwing the bits together, any more than that is overkill.

Incidentally, sometimes an O Ring definitely needs no grease. For example the O Ring grooves of high quality camera housings are, increasingly commonly, being treated with teflon nowadays - no O Ring grease required unless you've been idiot enough to damage the groove, but that's another story.

[davemanroe]

Yep, like Christian said, I wouldn't (and don't) use grease on my reg O-rings, and finger tight with a spanner is fine.

[ChristianG]

Yep, like Christian said, I wouldn't (and don't) use grease on my reg O-rings, and finger tight with a spanner is fine.
Thanks for the vote of confidence. :D

This is however more of a further response to the OP. He has apparently chosen not to be contactable either by PM or e-mail so I suggest to him that he look here (http://www.digigreen.net/forums/t7056/) if he wants to learn more on this esoteric subject. :)

It's a little out of date today, but it's a start and revisiting it reminds me that I should really update it.

[Adrian Hutchison]

Hi Guys,
Thank you all ever so much. your responses have been very helpful. Nice to see such a friendly bunch.
Thanks again,
Adrian

[davemanroe]

And remember, if in doubt, get someone from your club to check over for you.

[ChristianG]

I've had another thought. Your 1st Stage is of the "turret" variety. Most people mount these in the "up" position so that it sticks further up from the tank tap than that itself, but there are two pretty good reasons why this is a dumb idea:

1) If you are finning parallel to the bottom and wish to look ahead there is every possibility that the back of your head will make contact with this extended tank-tap-cum-turret thing. Ouch!
2) More importantly, if your tank goes A over T, and it will, the risk of damage to the 1st stage is significant because it's sticking up in the air.

Instead, configure it so that the turret parallels the tank tap. This way it is protected both by the shoulder of the tank and the tap itself. Furthermore, you don't get a headache.

I do hope, BTW, that you got one with a DIN fitting rather than "A" Clamp (http://www.ukrecscuba.org.uk/ukdiver/dinyoke.htm).

[Woz]

I've had another thought. Your 1st Stage is of the "turret" variety. Most people mount these in the "up" position so that it sticks further up from the tank tap than that itself, but there are two pretty good reasons why this is a dumb idea:

1) If you are finning parallel to the bottom and wish to look ahead there is every possibility that the back of your head will make contact with this extended tank-tap-cum-turret thing. Ouch!
2) More importantly, if your tank goes A over T, and it will, the risk of damage to the 1st stage is significant because it's sticking up in the air.

Instead, configure it so that the turret parallels the tank tap. This way it is protected both by the shoulder of the tank and the tap itself. Furthermore, you don't get a headache.

I do hope, BTW, that you got one with a DIN fitting rather than "A" Clamp (http://www.ukrecscuba.org.uk/ukdiver/dinyoke.htm).Turret up or your hose routing, especially with a drysuit hose, will be terrible. Have a play- whatever works, works, and your hoses should just be nipped up, not tightened really hard as it's only soft brass you're screwing into and it's easy to stretch the threads.

[TerryH]

The most common 1st stage turret in the UK is the Apeks DST
(Dry Sealed Turret).

Dry -sealed means that water doesnt actually go inside and instead
acts on a small window, which although is pretty tough, could get punctured
in a fubar. So for that reason it makes sense to always point the "window"
down, which puts the hose/turret on the top.

Now this doesnt stick up any more, because the longer bit from the center
line of the clamp is actually the window end, not the turret end, so again its
better window down, turret up.

Finally like Woz says swivel turret at the top allows the greatest movement
of hoses, so why wouldnt you want it on the top?

I know the OP was on about Scubapro, but we'd strayed into general
territory.