Barrel (with removable tops) questions and concerns

I love this design of RMH 55 gallon drum with a removable top, like in this video by Ernie and Erica...
Since there is no gasket, should there be much concern about fumes escaping into the room? I've read that the wood stove rope works as a gasket for this, but is it necessary?

I've acquired a few drums that have clamped removable tops, but there are threaded fittings in them (2") with rubber and plastic gaskets. So in order to make the Ernie version, I'll need to replace this with a top that's completely solid. Or is there a way to remove a crimped/ welded top so that it fits the way that's shown in the video?

Any sources for solid lids that would help with my design?

Thanks in advance for your thoughtful answers. -Peter

The band clamp that holds on the lid is a pretty tight seal even without a gasket although I think those type have some kind of gasket in the lid that would NOT stand up to much heat. The bungs are easily sealed on the removable lid. Just take off the gaskets and use furnace cement on the threads and screw them back in. You could use the furnace cement on the lid too, but a thin rope gasket would make it seal great. That way you could remove it easily for inspection and cleaning.

I used a removable lid type barrel, but used the lid for the bottom and cut a hole for the exhaust to go out. Lifting the whole barrel off isn't to hard.
I just used clay slip to seal the barrel to lid and screwed it together with a few screws.
My first try used a 4x10 floor register as the output duct connected to a 90deg elbow in to the floor duct. I later enlarged it, and made a larger manifold/transition area into the floor duct.
Here's the thread on the whole progression.

Peter Gallo : For a video of a completed later date ernieanderica.info build (I helped), goto> video: great rocket mass Heaters in upstate New York - - (rocket stoves forum at permies)

This one was made with the barrel turend upside down to mate with a 1/3rd of a barrel, Come back and I will try to answer your questions ! Big AL

Great photos John Adamz.

Is that the furnace cement that looks like silvery stuff on the edges of yr mortar joints? I'm not too familiar with the stuff.

How about your materials? Those are fire brick for the heat riser, right... and the others are just cement bricks? -Peter