I rust blued my muzzleloader barrel using Laural Mtn. Forge browning solution, boiled water on my camp stove, and used a piece of ABS drain pipe with a cap for the tank. It worked fine without boiling in the tank. Just cut a piece of pipe a few inches longer than the barrel, cap one end, then stand it up and put the barrel in. Pour in the boiling water and pull it out when it cools. Worked great.