Good Afternoon,

About six weeks ago I installed a compression fitting to a copper pipe, which was to be used for the dishwasher inlet.

The nut at the back was leaking a bit, so I put silicone around it, worked for six weeks and no noticeable leaking.

Today it just burst off, water everywhere.

This is the compression fitting that came off. You can see the white silicone on the right side of the nut.

enter image description here

Instead of getting another compression fitting, can I just put JB Weld on the back end?

The blue part is where the silicone was, I want to remove it and put JB Weld there.

  • Can you provide a picture of the pipe and where it connects to the washer?
    – JACK
    Commented May 11, 2021 at 18:03
  • 4
    Brass parts don't just pop apart when correctly installed. You have a problem with the assembly. Caulk and adhesives are not your solution. Show us some actual photos of your work.
    – isherwood
    Commented May 11, 2021 at 18:12
  • And please don't type in ALL CAPS. It's perceived as SHOUTING, and is harder to read. Commented May 11, 2021 at 18:25
  • Here is the picture: ibb.co/jJy9rfF that is the compression fitting that came off, you can see the white silicone on the right side of the nut. All I want to know is if I have to get another compression fitting. Or will JB weld do the job? how much pressure PSI is coming out of that valve Commented May 11, 2021 at 19:05
  • 4
    It came apart because when you were presented with a leak, which is a sure sign of a loose fitting, you goobered it rather than tightening it. That was a misstep.
    – isherwood
    Commented May 11, 2021 at 19:42

1 Answer 1


A compression joint that relies on any kind of sealant is a leak waiting to happen.

Sometimes the leak is very anxious to get started and begins dripping immediately. Other times the leak is patient and stealthy, waiting even weeks before POW! it soaks you and wreaks water damage everywhere.

Here are some things I've learned by experience:

  • the tubing must be bright clean and round where the ferrule will compress it
  • when tightening the nut ensure the tubing is very straight in the fitting. If it isn't the ferrule can be crimped onto the tube a little crooked.
  • don't over-tighten - IMHO a compression fitting takes less force on the wrench than a pipe thread fitting would. If it leaks under pressure you can tighten it a little more, but if that still fails, it'll have to be disassembled and inspected.

I suggest you disassemble the joint, carefully inspect all the parts for nicks, debris, and deformity, and replace parts as needed. In particular I'd consider cutting off the end of the tubing and try again with a new ferrule and meticulous cleaning of the tubing.

  • 2
    And stealthy enough to know when you leave the home for work/vacation. Boom, leak time. I wouldn't trust any type of sealant- this isn't that hard to repair the right way.
    – Jamie M
    Commented May 11, 2021 at 19:35

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