Assembling my own regulator set

[SouthSideScubaSteve]

Ok, so I want to assemble my new Airsource3 and Legend Reg set … 2 questions:

1) Should I apply any lubricant to the male threads on the MP hose or the female threads in the 1st stage?/ (if, so what type)
2) How do I torque it to 40 in-lbs (4.5Nm) with an open end wrench?? (I have a 3/8” drive torque wrench but can’t figure out how to use a traditional socket … Could I use a 3/8"drive Crowfoot-wrench and would that change the torque reading??)

 

[Tortuga68]

Yes you can use a crowfoot wrench - it won't have any significant effect on the torque reading

Or you can just do them 'firm' by hand with an oe wrench - 4.5NM isn't very tight (finger tight plus 1/16 turn, give or take)

IMHO there isn't any need to lubricate the threads - and dry means you won't have to worry about contamination

I've seen some people mention using Loctite - don't do that

Obviously check for leaks after connecting to the cylinder

 

[WozfromOz]

Just nip up the hoses so they are tight enough that you can't undo it by hand.... so only very lightly.

Be careful with a crowsfoot, if it adds length to your torque wrench then the torque is multiplied through it. An easy way to reduce this multiplication is turn the crowsfoot 90 degrees, which drastically reduces the multiplication factor.

The only place and I strickly mean the ONLY place you should even consider using loctite is on the thread to the yoke fitting. You should only consider this if you are having problems with the fitting coming undone and if you did decide to, you want to use the extreme low strength retainer and just a pin head amount. Don't use it anywhere else no matter what people say.

Woz

 

[herman]

I use a "2 finger" method for tighting reg hoses, install the hose by hand until it stops then just use 2 fingers on your wrench to snugg the hose, there is no need to crank down on it.
I also use a small amount of silicon grease on the threads of the second stages. My theory is that it reduces the amount of water getting onto the thread area and prevents salt water from corroding the metal or salt deposits from building up in the are. So far, so good, I have yet to have a badly corroded connection.

 

[Alpinesender]

One quick comment, from a thread design point of view. The manufactures recommended tightening torques are for dry threads. If you lubricate the threads and then apply the recomended torque you can damage the threaded joint as the lubrication increases the axial load and may shear off the threads at the root.

 

[Ed Palma]

Will lubricating the threads also mean an increase in the needed torque?
To the OP: Personally, I only lube up the o-rings. Food grade silicone grease is what's used, or christo-lube for higher PPO2 applications.
I also just snug up the connections after getting them finger tight using a very short wrench.

 

[Alpinesender]

Threaded joints that compress an o-ring or use a compression flange will require less torque to generate the necassary force to seal if the threads are lubricated. In the same way pipe threads which are tapered will take less torque to seal, but, these types of joints will work lose faster because of the taper (they use the dry friction in the threads to lock them).

I agree with using the lubricant on the o-ring. This will allow the ring to slide a bit and fill the o-ring groove without snagging during the process.