Originally Posted by seattlepitboss
I'm not sure I'd puncture the ceramic-coated lid of a Weber kettle just to add a thermometer hole. Because it will rust all around the hole.
I've only done one lid and that's on my mini-WSM. I've had an eyelet in my 18.5 WSM for several years with no problem. It seems that enough smoke/grease deposits on the inner walls to prevent rust (so far.) On my mini-WSM which has a silver barrel, the tracks where it runs down the outside are obvious (but not overly objectionable.