Low pressure BCD hose assembly question.

[ams511]

My gear gets more use than most recreational divers and my maintenance cycles are probably longer than recommended, but I never seem to have a problem with corrosion at the connections or O-rings popping out.

I think the prohibition on greasing orings and fittings come from divers that blend their own gas. It makes sense that when using oxygen you want the least amount of lube in a reg. For divers using air or banked nitrox there shouldn't be a problem giving o-rings and fittings a light coating of lube. I have had problems separating fittings on older regs that look like new, so I lightly grease them.

---------- Post added March 28th, 2015 at 03:19 PM ----------

I do not generally put grease on the static O-rings of hose connections as it is an opportunity for the O-ring to extrude.

I have never heard this before. I thought o-ring extrusion is caused by using the wrong size or durometer of ring or the ring is old and breaking down. Could you elaborate on this?

 

[knotical]

To lube or not to lube, that is the periodic question.

All o-rings are dynamic at least briefly during assembly, so light lubrication doesn’t seem completely out of line. They’re less likely to be damaged and more likely to seat correctly.

The Parker O-Ring Handbook (https://www.parker.com/literature/ORD 5700 Parker_O-Ring_Handbook.pdf ) says:

3.1.5 Lubrication
Lubrication of O-ring seals is extremely important for installation and operation of dynamic seals as well as proper seating of static seals. The general rule for use of lubrication is: The greatest benefit in using a lubricant is obtained during the initial installation of the O-ring.

On the flip side, Dive Gear Express (https://www.divegearexpress.com/hardware/orings.shtml ) says:

As a general rule, the O-rings used with static seals in SCUBA applications should not be lubricated at all. The lubricant just causes contamination to stick to the surface of the O-ring and results in more problems with a static seal than any dubious benefit the lubricant might provide.

So, who you gonna believe?

On the other issue of whether to lubricate threads, Fastenal (https://www.fastenal.com/content/feds/pdf/Article - Galling.pdf ) says:

Thread lubrication is one of the most effective measures to decrease the potential for galling.

 

[Centrals]

I also believe the hose is standardised throughout the industry?

You can buy them in various lenghts!
Take a look at divegearexpress.