The truth about gasket grease

[The Chairman]

111 is an industry standard. I would use it anywhere unless I needed it O2 clean. Of course if you really want it sealed forever, use some gorilla snot. It's yellow and gooey and you'll never get it open.

 

[tarponchik]

Is that grease for silicon or made with silicon?

It is silicon grease.

 

[bvanant]

The stuff at Lowes/Home Depot is almost certainly plain straight up PDMS grease filled with fumed silica. Not recommended for silicone o-rings but should be fine for Buna-N and such. In any case just get some Tribe/Christo/Krytox and use it for everything and stop worrying.
Bill

 

[The Chairman]

In any case just get some Tribe/Christo/Krytox and use it for everything and stop worrying.

I can agree with this.

 

[tarponchik]

The stuff at Lowes/Home Depot is almost certainly plain straight up PDMS grease filled with fumed silica. Not recommended for silicone o-rings but should be fine for Buna-N and such. In any case just get some Tribe/Christo/Krytox and use it for everything and stop worrying.
Bill

And why would anyone add fumed silica into a grease?! Basically, you are adding fine sand. Have you even seen it?

 

[Gr8WyattWhale]

+1 Krytox on everything and I don't think about it anymore

 

[bvanant]

And why would anyone add fumed silica into a grease?! Basically, you are adding fine sand. Have you even seen it?

That is why silicone grease is kind of white color. You add the fumed silica to it to make it thick. Almost all greases have some sort of particulate material in them for thickening. Some use Teflon/PTFE others use silica. The particle size of the fumed silica is quite small on the order of 15 nm or so and is quite a good and non-reactive thickener.
I think that Krytox (or some of the Krytox products; there are zillions) have PTFE fillers
Bill

 

[tarponchik]

That is why silicone grease is kind of white color. You add the fumed silica to it to make it thick. Almost all greases have some sort of particulate material in them for thickening. Some use Teflon/PTFE others use silica. The particle size of the fumed silica is quite small on the order of 15 nm or so and is quite a good and non-reactive thickener.
I think that Krytox (or some of the Krytox products; there are zillions) have PTFE fillers
Bill

I've seen my share of strange things happening, but calling a grease "silicone grease" because it has fumed silica added would still be unlikely. Also, it is stable to 400 F, typical for silicone greases.

 

[jseyfert3]

I've seen my share of strange things happening, but calling a grease "silicone grease" because it has fumed silica added would still be unlikely. Also, it is stable to 400 F, typical for silicone greases.

From Wikipedia:

Silicone grease is a waterproof grease made by combining a silicone oil with a thickener. Most commonly, the silicone oil is polydimethylsiloxane (PDMS) and the thickener is amorphous fumed silica. Using this formulation, silicone grease is a translucent white viscous paste, with exact properties dependent on the type and proportion of the components. More specialized silicone greases are made from fluorinated silicones or, for low temperature applications, PDMS containing some phenyl substituents in place of methyl groups. For food applications, the thickener is calcium stearate. For applications involving highly reactive substances, powdered Teflon is the thickener.

Basically exactly what he said it was, when he said:

The stuff at Lowes/Home Depot is almost certainly plain straight up PDMS grease filled with fumed silica.

(except he said PDMS "grease" when it appears PDMS is an oil)

 

[tarponchik]

From Wikipedia:


Basically exactly what he said it was, when he said:


I took a look at the page for PDMS and wikipedia says it one of several types of silicone oil. So basically putting 2 + 2 together, the silicone grease from HD/Lowe's is silicone oil thickened with fumed silica.

Right, my mistake. However, does the presence or absence of fumed silica make any difference here? We are just lubricating O-rings. We are not even greasing moving parts to reduce traction; we only keep the water out. I used the plumbing silicone with 2 housings, never had any problems.