Fluid Least Likely to Leak Through O-Ring?

[BasketDaN]

I am building a prototype, and I was just wondering what fluid I should use that is the least likely to seap through the interface of a steel rod and a small O-Ring, as the steel rod moves forward through the O-Ring. This fluid should not freeze at 25 degrees fahrenheit, and should be relatively incompressible.

Thanks!

 

[FredGarvin]

You need to select something that is chemically compatible with the elastomer the o-ring is made of. That combined with proper gland design will be the only way to ensure a leak free installation.

 

[BasketDaN]

This actually doesn't need to last long, just a day or two so I can use this once. High performance also isn't particularly important, just that nothing leaks out the seal. I guess I am wondering what the highest viscosity fluid would be that wouldn't freeze in a freezer. (Is it viscosity that would determine this?)

 

[FredGarvin]

Hydraulic fluid, engine oil, canola oil, glycerin, antifreeze, etc...pretty much anything that's doesn't have water as a major component.

 

[pantaz]

What's the surface finish of the steel rod?