Believe me with the torch it is plenty hot. The solder stays molten for several seconds after I insert the wire. This is why I have to hold it steady for several seconds. If you were heating it with a standard soldering iron I would say this statement is true.One thing I don't like about this vid - he needs to have the wire hot enough to melt the solder in the cup. The way he shows it, you will get a Cold Joint, which can break later. All that is needed - after you insert the wire, add heat (the torch) again for a few seconds, then let it cool.
Im certified in soldering (class 1, 2, and 3) and precision vertical tig welding and do it for a living everyday. The method used in the original post is fine. A cold joint usually only happens if the joint being soldered is moved around while in the cool off process.
And just a little tip, if your LHS has any 63/37, 60/40 solder sitting on the shelves you should grab it. New federal mandates are going into effect soon to eliminate all leaded solder. If youve never used lead free it takes some practice and usually more heat to get a class 2 joint. Our company has gone to lead free/low flux already, and several of our guys failed the recertification test when using it.