Why doesn’t solder flow evenly onto a tip though it is brand-new?

Even a new tip will start to oxidize and solder will stop wetting if the iron is left on for 30mins or more

	After iron has been left on for 30 min Tip temperature is 470°C (Measured with HAKKO FG-100)
New tip		Tip turns black due to oxidation Solder will not wet to the tip in this state even if the tip is new.

Turn the power on, wait until the solder starts to melt, and then feed a generous amount of solder to coat tip. If you then leave the iron as it is, you should be able to maintain wetting performance like that shown in the photo.