Non-silicone o-ring lubricant?

[jakulik]

Hi All,

Any suggestions for silicone-free lubricants that can be used to install a silicone o-ring into a groove? The reason we are interested in silicone-free is because silicone contamination is known to have a negative impact on various assembly processes and can result in adhesive failures.

 

[EdStainless]

I have used Snoop for this, it is Cl free. Don't use soap as nearly all soaps contain Cl, some of them 5%.

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P.E. Metallurgy, consulting work welcomed

 

[TugboatEng]

Silicone oils shouldn't be used on silicone o-rings in general due to the "like dissolves like" generalism.

With that out there, silicone rubber has broad chemical compatibility so I would pick a lubricant that is compatible with your process first and the o-ring second. You mention adhesives which can be similar to automotive paints. Perhaps some spray gun lube is what you need.

https://www.autorefinishdevilbiss.com/products/devilbiss/gun-maintenance/spray-gun-lube.aspx

 

[jakulik]

Thank you both for the reply. For more context, these o-rings are used to seal autoclaves. The autoclaves can heat up to 800F. We want to avoid silicone contamination due to off-gassing of the lubricant; silicone is expressly banned at some of our clients facilities.

What about ester oil or WD-40?

Btw is "Cl" an abbreviation of "silicone"?

 

[MintJulep]

Try

https://www.krytox.com/en/applications/o-rings

What temperature will the o ring experience?

800 F will be difficult.

 

[TugboatEng]

A paste of glycerine and graphite powder might do the trick.

 

[SuperSalad]

With temperatures like that, a lot of esters and WD-40 are definitely not going to be suitable if you want that lube to stay in place. Something like an oven lubricant or kiln grease would withstand those temps, but those are usually sold in industrial quantities so I don't know if you're going to be able to buy small quantities for installing o-rings. Check with your lubricant supplier for their recommendation for high temperature greases or oils.

Andrew H.

http://www.MotoTribology.com

 

[EdStainless]

Cl is chlorine.
You don't want/need a lubricant that stays around.
If you really need something to keep teh o-rings from sticking then wash the groove with some Boron Nitride (some of the powder dispersed in alcohol, or buy the very expensive aerosol spray cans).
For installation all that you need is some water with a surfactant in it to make it slippery.
Don't use an oil, and don't use Krytox, it will have the same issues as silicones (no solvent for it).

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P.E. Metallurgy, consulting work welcomed

 

[XL83NL]

800F for an O-ring. Is that even possible? Afaik, FFKM goes up to 327 deg C.

Huub
- You never get what you expect, you only get what you inspect.

 

[EdStainless]

The process goes that hot, the flanges will not get that hot I hope.
We used to bake o-ring sealed containers at 600F, hell on o-rings.
This was a combination of oil and water, we used AFLAS o-rings (6" and they were ~$800 ea).
The silicone o-rings on our vacuum furnace and the biggest problem was how easily they were nicked and torn. But for that size and the temp we didn't have options.
We used HBN in the grooves so that we could eventually get them out.

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P.E. Metallurgy, consulting work welcomed

 

[btrueblood]

Boron nitride is wonderful stuff, makes a good anti-gall/anti-weld coating for furnace fixtures/fasteners as well.

We don't do stuff that hot, but do use propylene glycol (neat) as a non-silicone o-lube for customers who request it. It's food grade and safe, and a bit cheaper than glycerine...or at least it used to be before all the people doing waste oil to diesel converting. Both liquids do a fair job of being sticky enough to keep an o-ring in the groove when assembling upside-down or vertical grooves or other awkward configurations.