Using foam as a core for vent adaptor

[Eric Pfeifer]

To make a gentler transition from square to round (in order to adapt to the Duratech pipe) I made this foam core and shaped it with hand tools to the desired form. I set in in snug in the square vent hole and poured the vent/flue around it, then set the adapter plate into the wet cement. When the cement had cured, I pushed the core down out of the vent, and attached the chimney. I don't know if all this trouble was worth it, but my oven leaks absolutely no smoke into the house. The draft seems perfect.