Lubing O-rings and seals for potable use

[Carbon]

In installing O-rings and seals, you usually want to lube the seal. For food and potable water equipment, this is normally done with a food-grade silicone lubricant.

Is the job of this lubricant pretty much done within a short time after reassembly, or is there some lingering job the lube performs. Is there a practical advantage in higher or lower viscosity lube for this job, or is it just whatever is convenient to the installation process?

If this O-ring is making a seal that slides (such as a water softener valve piston) vs one that stays between two pieces that do not move, how does that affect choices?

 

[bullwinkle]

I use food grade petroleum based lube on o-rings all day long, usually Petro-Gel or similar, it stays on moving parts to help with sealing or wear. Since it's similar to Vaseline, I use it on auto projects as well, since it just melts off when it gets hot.

 

[Merkava_4]

Dow Corning one eleven is what the water softener guys use for lubing o-rings and valves.

 

[Carbon]

I see that was called Dow Corning® 111 Valve Lubricant and Sealant http://www.dowcorning.com/content/news/iam_news32.asp

I also find this 2011 document http://www.dowcorning.com/content/publishedlit/Dow_Corning_111_Molykote_111.pdf which says "Dow Corning is changing the name of Dow Corning 111 Valve Sealant & Lubricant to Molykote 111 Compound.

The word "Sealant" seems to say there is a function that goes beyond lubrication to help the seating of the seals.

 

[buck91]

I believe both Triflow synthetic grease and Superlube multi purpose grease are rated "H1" for this type of application.