Anybody have any idea what the vent of the typical neapolitan oven is composed of? I've attached a few images that illustate what I'm referring to... this is the rounded portion of the front of the oven above the landing. Behind this rounded structure would be approx 8" - 12" of space for smoke / exhaust to follow a path to the chimney pipe above or behind the dome itself.
My thoughts are...
a. refractory concrete over lathe?
thoughts: hmmm.. could be.. would the lathe material stand up to the temp? The inside wouldn't be smooth though.. which one would think would create turbulance..
b. pressed / formed steel (or other metal) with grout and tile just applied to the exterior?
thoughts: inside would be smooth, but wow..., you'd think the metal would expand and contract and crack the tile/grout on the exterior... would the metal stand up to years of use?
c. split brick that's been stucco'd and tiled over... maybe supported on the lower perimeter by a metal frame?
thoughts: could be a i guess... a metal lining does seem to support the oven entrance on all of these ovens (the half sphere arch)... and the lower perimeter of the vent as well.. could be...
The concept of venting the oven over the dome is well established in neapolitan ovens as witnessed by discussions here and many photo's of neapolitan ovens (again.. see attached)... The link here also at least somewhat supports the notion, though the oven being built is not a neapolitan oven... Vent construction begins somewhere down toward the last of the photo's: http://mha-net.org/docs/v8n2/wildac06b.htm
What do you guys think? Any mason's out there that may have an idea?