My local Gunsmith, use to perform hot bluing but eventually got out of it. Instead, he sends this work to a trusted shop and the results are super. Suggest you get some input from, your Smith. Another alternative, is to attend one of your local Gun-Shows and dealers will be more than happy to make recomendations. I have seen some very good cold bue work but don;t trust any of them......Take it to a gunsmith that does blueing, cold blueing is junk and wont last. He can add it to another batch and wont cost much.