How hot does it have to be to melt metal?

You need to define "metal"- since different metals have VERY different melting points. Mercury is melted at room temp. Gallium can melt in boiling water. Lead and tin are mixed as solder, and melt at fairly low temps. Gold and silver melt at moderate low temps. Aluminum is higher. Steels and hi temperature tungsten alloys will glow white hot before melting. So- which metal did you have in mind