I am a new to blacksmithing, and am trying to build my first smithy. I have basically everything done but a chimney. Previously I have been hung up on a super sucker or other side draft/sheet metal style chimney. This last week I was discussing with my dad what makes a chimney a good chimney, and the point came up if the outlet draws more than the inlet (to create the suck) it would work. So my question is I have a piece of 22" steel casing about 5' long, if I took about 2' of it and put lids top and bottom with a 8" arch in the side/bottom with a 12" pipe venting it...would that work? Thanks in advance for y'all's advice. Here's a couple of pics