Craig Dabler - The DIY Castings Guy | How to Add an Emery Finish to the Inside of the Wedding Band @craigdabler-thediycastings7511 | Uploaded November 2019 | Updated October 2024, 1 hour ago.
Using little mandrels with emery paper, this is how I add a smooth finish. I prefer 220 and then 400 grit using strips of emery cut about 1inch wide by 4 - 5 inches long.