So I made the same mistake as Cioffi and now I've also got a 1-3/4 hole in my kettle. I live in an apartment, so I'm unable to weld a spud into place myself, nor do I know of any reputable welders in my area (Chicago) who could help me out. I'm looking of going the route of using a reducer with a large stainless washer and O ring, but I wanted to verify that I was purchasing the correct size of all parts before proceeding.
Reducer 1-1/2 Male NPT to 1" female NPT
O-Ring 1-1/2 nominal ID
Washer 1-1/2 BOLT SIZE
Or, if you know anyone in Chicago who wouldn't laugh in my face for a small task such as welding in a spud into a kettle, please let me know!