In plumbing, an olive is a small piece of metal that helps to create a water-tight seal between two pipes.
A plumber’s olive is small and it kind of looks like a miniature gold ring. However, in certain cases, it may look more spherical and “rounded”.
A photograph of a brass plumber’s olive. Sometimes, people will refer to these as “ferrules”.
Typically, you will come across one of these if you are using a compression fitting to join two pipes together.
Plumbers will place the olive inside a nut and then tighten it onto the compression fitting. As the nut tightens, the olive will squeeze and wrap itself around the pipe. This, in turn, creates a watertight seal.
It fits inside the nut.
As you can see in the image above, it is small enough to fit inside of the nut.
How do I use an olive?
Firstly, start off by putting the nut onto the pipe. Remember that the threads of the nut should be facing towards the open part of the pipe.
After that, slide the olive onto the pipe and then push it into the nut.
Attaching the fitting to a copper pipe.
Once that has been done, attach the compressor fitting onto the pipe and then begin to screw the nut onto it.
Tightening a compressor fitting properly.
In most cases, tightening the fitting using your hands will not be enough. More often than not, you will tighten the nut and then discover that the pipe slips right out.
To tighten it properly, you will need to use a wrench / spanner to hold the fitting still. Then, using another wrench, you will need to tighten the nut.
Note that you do not need to overdo this. Simply tighten the nut until you feel it “bite”.
Why is it still leaking?
Unfortunately, using an olive by itself is not always enough to create a watertight seal.
This is why many plumbers will use additional products when joining pipes together.
To guard against leaks, you can put a jointing compound on the pipe that you are connecting the fitting to. One popular jointing compound is from a brand called Fernox. However, you will find a number of different brands and products at your local hardware store.
When applying the compound, simply rub it around the outside of the pipe. Usually, you will only need to cover about an inch, starting from the end of the pipe.
After that, you can slot the pipe into the fitting and then tighten it as normal.
Alternatively, you can also buy PFTE tape (plumber’s tape) and place it on the threads of the compressor fitting. The nut will then tighten over the tape and help to create a watertight seal.