To solder copper pipes, start by using a sharp blade and scrape the end of the pipe you are going to solder. This will get all the burrs off of the pipe. Next, take some steel wool and clean the pipe so that it is nice and clean and shiny. The next step is to apply some flux. Use a rag to apply the flux to the end of the pipe. You want to make sure that the flux goes all the way around the pipe. After putting flux on the two pieces of pipe, put them together using the fitting. Take the blowtorch and light it. Apply heat to the pipe with the blowtorch for a couple of minutes and the joint will be sealed. Before using the pipe, it must be flushed with water to wash out the residue that is inside the pipe.