At level 43 magic you get Superheat Item which give you 53 magic experience from. It lets you turn ores into a bar without needing a furnace..

 

My question is do you get all (or any) smithing/smelting XP from using it? thanks

Yea, you get smithing XP when using Superheat item.

 

It's not the full amount, if I recall. Something like 1/3rd maybe. I forget.

 

But, yes, you get smithing xp.

I get 37.5xp when smelting Adamantite bars with superheat, which to my knowledge, is what you receive for normally smelting bars.

thanks (^.^)