I'm going to use an existing burner....one that I've been using for about a dozen years. I'll get some pics of the burner, and will explain how its build. In my opinion, burners tend to be the part of a forge that most people try to "over engineer", and in doing so, are generally the causes of most forge issues. The one I used is a simply, single forced air burner. The first rule for building any forge in order for it to be useful and reliable is K.I.S.S.