Phil Stevens wrote:The cob cracks because the barrel expands and contracts a lot more than it's able to accommodate.
It’s funny how hind sight is 20/20, Phil. I came to this forum before installing the iron stove door and it was recommended to use rockwool, which I did, to allow for the difference in how the materials expand and contract. What’s funny, I guess, is that I did not extend that logic to the part of the stove that clearly has a lot of movement because of its location. Amazingly I’ve noticed the top of the barrel (technically the barrels bottom but in this case the end that is facing the ceiling) protruding past the the rim where the wall and barrel head are joined together. This was thrilling to me because I know the barrel wasn’t like that before and it only happened after applying the cob around it. This makes me think that, even though the cob is cracking, it may be creating enough resistance so that, as the barrel wants to expand, it is limit and finds the path of least resistance: where it’s uncovered. It could be other reasons but none the less something very interesting.
I appreciate all the replies and what you have all recommended make sense. I’ve thought of all the things you’ve recommended so it’s confirmation that, truly, the simplest explaination is probably the correct one rather than me looking for some “magic-bullet” alternative. The rockwool, like i used for the stove door, is the solution I’ll most likely go with. Seeing as how, after approximately 3 years of using this stove, I’ve finally given it some of the finishing touches, I think that I will make the cracks into a design feature when I do the final layers of plaster, and when I eventually rebuild the guts of the stove I will redo the barrel with the rockwool. Interestingly, even though the cracks at the thinnest sections of cob on the barrel are fairly deep, everything is intact because of the straw in the cob mix is acting like structural fibers holding everything together.
Certainly, if anyone else has any cool ideas or experience similar to mine I’m all ears. And thank you all very much for the comments on the appearance of the stove. There’s something about natural building that speaks to me like no other kind of construction. It connects to a mysterious part of myself with knowledge and experience that I don’t think I can fully claim is from my own experience. Even though I had an idea of what I wanted it to look like, when you get down to it it kind of becomes what it’s going to be in the process. Cool stuff.
I’ll attach a couple other pics below
