Temperature regulator for soldering iron up to 300W

The right temperature of your soldering iron is super important, to make nice soldering points you need to melt the tin completely and with lead the top layer should just liquefy. 

So if you work with wide lead (e.g. >10mm), you have to solder hotter than if you use narrow lead because otherwise you will be too hot and push through your lead.

You get the nicest soldering points if you solder just hot enough and fast, the soldering points then look nice and flowing.