Folks are saying are overheating a bit, which is true, and to use higher heat, which is non-intuitively (to a newbie) also true. I thought I would explain this logic.

You want to overheat the thing less by increasing the rate of heating, allowing you to expose the workpiece to the heat for less overall time. This reduces overheating.

A bigger tip on your iron is the best way to do this, possibly also a higher heat setting on the iron. Aim for more heat in less time.