Solder took too long to melt. I measured the temperature of the tip with a thermocouple and although the display showed 720F it was actually 550F. I increased it to 800F and the same 550F. Lowered it to 500F and it showed 300s. Just to make sure it wasn't my thermocouple's fault I put some solder on the tip at the 500F setting and it didn't melt. The solder had a melting point of 422. I liked the display and the feel of the iron, but if Weller produces this quality in 2018 I will avoid it. I returned the device and bought a product from another manufacturer.