Dow Corning 7 VS 111 and dual versions of Christolube and Tribolube

[Rusty Shackleford]

Gentleman,

I noticed Mr. Wolfinger sells (currently out of stock) Dow Corning Silicone Grease 7 for dynamic o-ring applications and 111 for static and packing application.

I also note there are two versions of Christolube and Tribolube respectively for dynamic and static/packing applications.

One would assume that the more expensive dynamic compounds could also be used for static applications.

The whole crux of my question is I appeared to have discovered something new in the world of scuba and lubes. Gentlemen, what are your experiences and opinions?

Is anyone using Dow Corning 7 for dynamic o-rings? I know the previous board consensus is use 111.

 

[happy-diver]

O2 creamy stuff sparsely inside regs, and valves
heavy 111 on all threads outside sealed sections
for future pulling apart, after much salt water use

and sparse 111 on low pressure rebreather stuff
including pure o2 rebreathers, loops and fittings


Silicone schlepp is for plumbing not inside regs

 

[rsingler]

Tribolube over Christolube any day of the week.
It's a bit cheaper, but most important it doesn't appear to dry out like Christolube does. You know that white film in old regs that you can't remove to save your life? That's Christolube. Tribolube 71 doesn't do that. It just stays moist. And T-66 is much cheaper for static o-rings.

And one minimally scientific thing my first repair instructor (Rudy Mola) showed me when evaluating Tribolube for the first time for oxygen service: when you take a small lump of MCG-111 and fire a propane torch at it for 30-sec straight, it eventually glows red. But Tribolube just sits there gray and silent.

 

[Rusty Shackleford]

They are both PTFE based. If you get Teflon just north of something like 500 degrees, it will devolve into hydrofluoric acid.

 

[rsingler]

Yes, that's the same argument used against Viton o-rings in oxygen service.
I am only pointing out an odd characteristic that conceivably supports ongoing combustion. But at that point you have bigger problems, anyway.