There are many ways to seal pipe threads and connections. These are just some of the ways I have personally done it in the past two decades. Made a lot of plumbing repairs with brass, copper, black iron, pvc and others for plumbing and gas line connections. I'm no expert but this is what has worked well for me in the past. I'm also positive that many complete their repairs in different manor(s). So in different parts of the world or even the USA, you might see things done different. These suggestions can really help with new or old connections and help repair leaks on the job or even in your home. Last I didn't included it in the video, but the cotton string does work lovely on steam connections. I just haven't worked on steam in over a decade. Enjoy, and leave your comments if you please. Thanks.