Steel Oven Vent or anchor plate Specs for 42 inch

[Carlos]

Hi-
The Pompei plans are a bit "open ended" with respect to the metal oven vent. From what I understand since it is somewhat embedded in the oven's structure (sealed with mortar and surrounded by insulation) I do not have to purchase a specific type of vent (Unlike the metal chimney that has to be 8" double walled, right?)? My question is, if my opening 6"x10" and my chimney is double walled, where might I find a compatible vent? Does this need to be custom made?
Would it make more sense to go with an anchor plate? If so, what should the new dimensions of the opening be?
Sorry for the barrage of questions I'm just a bit confused...
Thanks

[rbirchell]

Re: Steel Oven Vent or anchor plate Specs for 42 inch

I built my chimney transition out of firebrick. My opening ended up being 15 inches wide by 4.5 inches deep. A 30 degree angle created a taper over 4 layers to the 13.5 x 13.5 inch top layer of firebrick; cut with a circular opening for the 8 inch pipe anchor plate. Try stacking fire brick and draw a line to mock the taper. Then measure the angle. In my case, the 30 degrees worked in both dimensions as I reduced to 8.5 inches and widened to 8.5 inches for the anchor plate opening. The 8 inch anchor plate is 12.5x12.5. The chimney transition stays flat across the front of the vent arch and tapers back over the dome as it widens. I kept the chimney transition off of the dome. I was concerned about the expansion forces. I'm not sure if others were as well.

I then cut some tapered wedges to minimize the dead corners near the top. And coated the inside with mortar to make a smooth flowing surface.

Your 6x10 inch vent should work as it is larger than the 50 square inches (inner area) of the 8 inch pipe.

The red lines follow the inner taper.







I know this is apples to oranges, but the Duratch info has a table that indicates a 20 inch fireplace opening should have an 8 inch pipe. The fireplace people said they install primarily 6 inch. I have no experience to back up one of the other. I'll have 7 feet of chimney over the transition. We'll see how it vents tomorrow after the chimney is installed. I did 2.5 days of propane curing at 300, 350, and 400 degrees. Time for wood and higher heat. I don't trust the propane hose at the higher temps. An all metal propane weed wand might be the trick though.

Good luck.