Hi, I need more advice please about my top-venting Grandpa Bear. There is a 1/8 gap at the back of the 8" single-wall stovepipe where it enters the stove. The end of the stove pipe is out-of-round right around the vertical seam. I think it's a design flaw of the pipe. The seam acts as a kind of "hinge" so I don't think pounding the pipe out from the inside would help. I tried adding tin foil or that black Rutland stove cement into the gap but it is not a lasting solution and seems that it just encourages the gap to grow wider. BUT, I have always have a very good draft. I never see smoke coming out, but I can smell it. How does the gap effect the efficiency of the stove? Should I just let it be? How about using a few nicely placed 1/8 steel pop-rivets to close the gap? Or is there some no-no associated with that?