First keep the tip tined with fresh sod. second heat the item to be connected, then apply sodier. If you are going to really heat it up put a heat sink on item so you don't fry it.
Warning: Pay attention, don't grab wrong end of iron,{ask me how I know} you will only do it once.
Also there is a item called sodier wick that is a braid copper that will remove hot sodier also a sodier sucker.
Charlie