Pro Handyman Blog

If you are going to solder copper plumbing pipes, there are steps that must be taken to guarantee a leak-free joint. When soldering copper (also called “sweating”), you first need to clean the surfaces to be joined.

If you have any leaks, they will usually be located where a fitting meets a pipe. If you take the necessary steps, you can avoid these problems. Start by cleaning the surfaces to be joined. Use sand cloth and hold it to the end of the pipe with your thumb and forefinger. Rotate them around the end of the pipe until the copper looks like a shiny new penny. Next you want to clean the inside of the fitting. You can do this with a wire brush, sized for the diameter of pipe you are using. Place it in the fitting and rotate it to get the inside of the fitting shiny. Do not touch the areas you have just cleaned! Oils from your fingers can impede the flow of solder and flux and give you leaks.

Now comes the flux. Flux is an acidic etching paste that etches the surfaces of the copper. Flux removes oxides and allows the solder to flow. You can use a flux brush and wipe on an even amount on both the outside of the pipe and the inside of the fitting. Push the pipe into the fitting until seated and wipe off any excess flux.

Here are some details on soldering copper pipe.