Silicone Grease, All the Same?

[divinh]

For starters there is no such thing as silicon grease. Grease is an oil or fat based lubricant. Silicon is an atomic element that among other things can be used in a lubricant. There are also water based lubricants too. It really helps to use the right terminology (even for the mfg.). And no not all silicon lubricants are the same.

We're discussing *silicone* grease.

 

[DIVEWATCHDOCTOR]

Silicone grease is a very important part of sealing and I think is totally underrated. It fills the micro fissures irregularities in the O-ring and the sealing capacity is increased considerably. It prevents the Oring from drying out and disintegrating under pressure. Lubricates the slight movements between the two parts as the external pressure varies. Proper maintenance of O-rings can prevent a lot of accidents. Devil is in the detail.

Manjula Ellepola got it 100% right.

 

[Scuba Lawyer]

Still using silicone grease that came with my Nikonos III several decades ago. Seems to be the same viscosity as my tub o'Trident. M

 

[divinh]

I ended up buying 2 oz of Trident Silicone Grease. The battery has been replaced in the dive computer and I have tons of silicone grease left. Hahah...

 

[CT Sean]

I ended up buying 2 oz of Trident Silicone Grease. The battery has been replaced in the dive computer and I have tons of silicone grease left. Hahah...

I have that same 2 oz tub - it's definitely more than enough for several lifetimes of miscellaneous o-ring lubing.

 

[davehicks]

I have that same 2 oz tub - it's definitely more than enough for several lifetimes of miscellaneous o-ring lubing.

I must be burning the candle pretty fast then, I go through one of those 2oz tubs every year. With a Camera, Rebreather, DryGloves and their constant demands for lube I can barely keep it in stock!

 

[runsongas]

silicone grease on a RB sounds ... risky ...

 

[davehicks]

silicone grease on a RB sounds ... risky ...

Not at all. Most of the unit is running at ambient pressures. Lots of orings and fittings for lungs, canister, loop hoses. No risk of O2 issues at normal pressures. Obviously the regs and O2 injectors require Cristo Lube.

 

[Hatul]

I use a little grease on my DIN threaded fitting, it makes it easier to connect and less likely to jam. A very tiny amount on the O ring can't hurt either.

 

[herman]

For the faucet head, one of those rotating kitchen ones, the o-ring alone allowed for water to leak. Once the silicone grease was applied, no leaks ,then the faucet head could be rotated as desired without issue. From that, it does appear to seal as well.

You misunderstand function of the silicone. It does not seal but rather lubricates the interface between the oring and faucet shaft. It allows the oring to slide freely against it's sealing surface which keeps the oring in proper alignment. The reason it leaked before silicone is because the oring was being deformed as the shaft of your faucet moved which allowed water to pass. The rubber to metal contact did not allow the oring to slide so the oring bunched up, creating a path for water to escape, once lubricated, the shaft slid in the oring, keeping the oring in proper alignment and the seal working.

This is the reason any oring, in scuba or not, needs to be lubricated if AT ANY TIME the mating surfaces and the oring move past each other. An example of one of the few orings that do not need lube is the yoke style valve oring, since the reg face is pressed directly onto the oring without any sort of linear or rotational movement, it does not need lube.