I had to do some thinking on how I was going to attach the hopper to the hearth. I decided not to make another set of flanges. Instead I did this:
A ring inside the tank, tack welded in place and slips right in to the hearth section. I cut it from the same water heater tank that the hearth section and the hopper were from. I cut it open, trimmed a bit off and rewelded it in place:
So now they fit together like so:
You can see I added a spout for the condensate drain. Cut from my supply of 20' pipes. Ugly weld, but airtight:
So once the two sections are together, I need to ensure an airtight seal. Again I cut a ring from the water heater:
And like so:
The whole thing together:
It's getting closer. I still have to work on the lid, tuyeres/air intake, and the second flange. Plus a bunch of other stuff.....