What kind of “oil” on compression fittings

[Sokolq55]

Lots of mentions about using a “drop of oil” with compression fittings. What specifically is meant by that? Can I use some faucet grease for the same purpose?

And on a related note, is faucet grease the best thing to use for lubrication various rubber parts like o rings, etc.?

 

[Reach4]

People suggest a drop of oil, or pipe compound serving as a lube, on the threads.

Some suggest some pipe compound on the ferule as well. I have limited experience, but I like the pipe compound. I can see silicone grease on the ferule being helpful to help the small flow of metal too.

 

[Sponsor]

 

[Mr tee]

I use a drop of light oil on the male threads.

 

[John Gayewski]

Any greases you use on rubber or plastic must be non petroleum based such as silicone grease. I usually use dope on compression. Generally I put the ferrule on the tip of my finger and lightly dope the outside of the ferrule.

 

[Sokolq55]

I use a drop of light oil on the male threads.

But what specifically is it? I assume like a kerosine/gasoline type light oil and not a light cooking oil?

 

[Jadnashua]

It isn't 'needed', but it can make it easier to snug up the compression nut. Otherwise, especially with some of the cheaper Chinese stuff where the threads aren't cleanly cut, the nut can 'stick' a little as you try to tighten it up, sort of jerking rather than smoothly rotating until you get it where you want to.

The whole idea is to lubricate the threads so it tightens smoother. Almost anything...a short sprite of WD40, a little dab of plumber's grease, a small drop of sewing machine oil, whatever, even take a bar of soap and rub a little on the threads. You don't need much, and you don't want lots. You don't want to contaminate the end of things so it might get into the water or you'll taste it for awhile. That's why silicone plumbing grease is good as it's okay for potable water.