Neil, it may be warped a bit. I've noticed it more on the 26's. My 22 was fine but I have seen them where they don't sit flush and kind of wobble. This may sound a bit extreme, I never did it on my 22 but I have on the 26 and that's a ring of Nomex. It takes up any warpage and seals up any spaces between the bowl and the lid. You would not need much. I used something like 7 feet for the 26. I only did it because of the LNS I'm doing and the weight of the lid. I've seen 26's chipped around the top edge of the bowl. But now that I've done it, I would use it on a 22 as well.