Fill cast iron holes through brazing.
Brazing is a process of joining two pieces of metal by a third piece of metal melted between them. The melted metal is called a filler and the two pieces that need to be joined together are called wetting. The filler metal is distributed between the two metal parts by capillary action. You can repair cast iron and other metals this way. Brazing, like soldering and welding, uses a flux. This is a chemical agent that facilitates the process by removing oxygen from the metal needing repair.
Instructions
1. Inspect the part of your cast iron structure that needs to be repaired to check the amount of flux you need. The the most common brazing flux is borax, also used for braze-welding.
2. Prepare the cast iron parts that need to be joined together. Use a hand grinder tool to thoroughly clean both parts of the cast iron structure. You can use a wire brush instead of a grinder.
3. Preheat the cast iron to 300 F by using an oxy-acetylene torch. Preheat the cast iron locally, only on the part you wish to repair. This technique will further prepare the cast iron for the brazing process by removing any water from the cast iron. Make the preheating slow and gradual.
4. Apply the borax flux to the cast iron while it is still hot from the torch. Use borax, or a similar flux, in a form of a powder or a paste.
5. Heat the flux with the oxy-acetylene torch to melt it completely. The flux will then use capillary action to penetrate between the cast iron parts and join them firmly.
6. Use the torch to keep the temperature around 300 F for half-an-hour to an hour. This will allow the cast iron to settle with the flux and let the joint cool off slowly. As with preheating, the cooling off process needs to be slow and gradual.
7. Leave the cast iron to cool off completely when the repaired place is tightly joined and firm.
Tips Warnings
Other than borax flux, you can use copper-based and nickel-based flux rods.
All kinds of welding and brazing are fairly dangerous so use extreme caution and proper protective equipment.
Tags: repair, cast, iron, brazing, cast iron, borax flux, capillary action, cast iron, cast iron parts, cast iron structure
