Question: [![enter image description here](https://i.stack.imgur.com/1gO9Z.jpg)](https://i.stack.imgur.com/1gO9Z.jpg)

Hi there, 

This is some piping to my Saxon hot water system. Just above where the white/green corrosion is is where the leak is.

My question is, can I use plumbers tape on the outside of this to seal the leak? 

I do not want to pull it apart as I don't know what I am doing. I am basically after a quick fix and thought plumbers tape (teflon tape) would suffice. If not are there any other options? (other than the obvious in getting a plumber out (again!).

Answer: 
Your other option is to ditch compression fittings and **learn how to sweat** (solder) copper pipe. Or if you do have a plumber come out, have them replace every accessible compression fitting with sweat fittings that will never leak ever again.

Compression fittings are prone to leakage, even when they aren't eating away your pipes with galvanic action, as you can see they are, with the black patina on that old stub.

I'm pretty sure **Stack Exchange can help you** with every aspect of learning how to solder, and if you're willing to do the work, the cost of the tools and materials will probably be less than a service call, and then you'd have the tools and the talent for work in the future. Having one easy elbow to sweat is a great place to start.

If you know anyone who knows how to sweat pipe, they should be able to show you how, *and* you'd be done, in under an hour: for the cost of a torch, solder, flux, fittings, a piece of sandpaper and a six pack of beer.
You should first turn the water off at the main. ( where the meter is located, usually in the front by the curb) Have a bucket close by to catch what water is left in the pipe. You should be able to turn the bolt just above the corrosion to the left and loosen the connection. Pliers may be needed if it hasn't been loosened in a while. After loosening, it should disconnect enough where you can maneuver the pipe out from under the bolt. Take a look at the pipes condition. If it's threads are still visible and the pipe is still in good shape with the corrosive material mainly where the dripping is on the outside, then u can apply a layer of plumbers tape around the threading and reconnect. The tape otherwise will have no affect on the leak without taking these steps. If the leak continues or the pipe is deteriorating, then disconnecting both ends of the pipe and taking a trip to Home Depot will probably be necessary.