Thoughts on jointing compound for compression fittings?

[spintop]

Would you recommend using jointing compound on newly installed compression fittings? Some say use it always while some say it affects integrity of joint.

 

[ShaunCorbs]

Yes unless your using high quality fitting

 

[Best]

This subject has been brought up very often.
I say you should always use paste and the cheaper fittings especially.
It won't affect the integrity of the joints.
Any MIs stating jointing compounds not needed are wrong. Joints can weep microscopically without paste.
Another advantage of paste is it lubricates the joint allowing it to be compressed much easier and without squeal - that alone makes paste essential.

 

[deg]

It's a yes from me

 

[king of pipes]

Always use a jointing compound one suitable for potable water on compression fittings cheers kop

 

[Chalked]

Compression joints on heating systems are subject to positive and negative pressures. Jointing paste helps the friction between, so aiding the tightening. Also helps to stop air being drawn in at microscopic level, when under negative pressure.
It's an added form of joint security.

 

[spintop]

Apologies on bringing up the subject again was not aware that is a common question. I tend to always use jointing compound just questioning due to a few people saying should not use it. Cheers great info as always.

 

[Chalked]

Obviously.anything compression onto plastic should be treated differently.

 

[Old Account]

I also use always jointing compound were possible except from plastic. I definitely see the difference in using jointing compound. But again, it's down to the engineer itself. You will have a lot of people they don't care and don't use it at all or you have got people using it everywhere.

As KOP has mentioned, you should use the right jointing compound which is suitable for potable water.

I heated that the jointing compound will fill the microscopic scratches on the copper pipe which makes then a good seal.

 

[Chalked]

@Best
Is the dislike real, or just bug thumbs

 

[Best]

Compression joints on heating systems are subject to positive and negative pressures. Jointing paste helps the friction between, so aiding the tightening. Also helps air being drawn in at microscopic level, when under negative pressure.
It's an added form of joint security.

I agree with you it is a belt and braces method to paste.
But I disagree that it is potentially causing problems with air in heating systems. That would therefore mean that not using paste could also allow air to be drawn in, given the fact that compression joints not pasted are always a gamble.
My thinking is the olive and fitting are still a near bare metal to metal contact when tight and the paste just provides a fine seal for any imperfections.
I have sealed heating systems that will barely drop pressure even slightly in several years and also have no problems with air. They are all copper though.

 

[Best]

@Best
Is the dislike real, or just bug thumbs

Lol! No, just revenge thumbs!

 

[Chalked]

That was bad text on my part. I meant that paste helps to NOT allow micro leaks.
Edited my original post.

 

[Best]

That was bad text on my part. I meant that paste helps to NOT allow micro leaks.
Edited my original post.

That explains it! I removed my Dislike because everything you said I now agree with.
What do you disagree about my first post, out of interest?
Is it because I think paste should always be used?
(Don't remove your Dislike, as it is fair enough if you dislike or disagree with any posts. We all have our own ideas. I need to collect some Dislikes anyhow)

 

[Chalked]

Honestly didn't mean to. ,!
They are too close together

 

[Best]

Honestly didn't mean to. ,!
They are too close together

It happens when you have big paws.

 

[spintop]

cheers once again, don't like plastic fittings copper is king.

 

[Dane Plumbing]

It's like insurance. You don't always need it but it's good to have just in case.

 

[AWheating]

Best practice , just a tiny smear tho, too much and filters and valves could get blocked up