Yup use a propane torch for sure. Feed in lots and lots of solder. Just don't put too much, or the wire will not be as flexible.Like said above, there is a crimping tool. What I do is take the ring terminal and heat it with a torch and put solder in it. After it is melted I just put the wire over in it and then it is nice and tight once it cools down.. That has always worked for me.