I have already suggested to the op to buy a hand held gas torch and a beaten up instrument and practice taking it apart and reassembling it to get some experience. I will take this further and offer him free Skype lessons in how to. I learned how to solder 70 years ago and am reasonably adept in all forms. There are many videos on youtube, the latest I have seen is a lass fitting an adjustable gap receiver to a trumpet under Jason Harrelson's direction. I am still learning.