How to Weld-Repair a CF-8M Casting

Welded CF-8M casting is as strong or stronger than the origional casting mold.

Metal castings such as the CF-8M enclose important mechanical parts. Over time, as these parts operate, the surrounding casting becomes worn or cracked. However, rather than replacing the casting, repair it. Weld your CF-8M casting to repair cracks, holes and crevices. The do-it-yourselfer with minimal welding experience can repair a casting in one to two hours, depending on the severity of the damage.

Things You'll Need

• Degreaser
• Stiff-bristle brush
• Wire brush
• 4-inch right-angle grinder with metal wheel
• Stick welder
• Spray bottle
• Chipping hammer

Instructions

1. Clean the casting with degreaser. Spray on the degreaser liberally, and allow it to sit for 15 minutes. Spray on a second coat of degreaser, and scrub the casting with a stiff-bristle brush. Wash it off with warm water. Allow the casting to dry completely, or spray compressed air over the surface to remove water droplets.

2. Clean the cracks and the holes with a wire brush to remove loose flakes of metal. Wear safety glasses to protect your eyes from wire and metal.

3. Grind the cracks and the holes with a 4-inch right-angle grinder. Turn the grinder wheel on its side and grind the cracks into a V-shape. Returning the grinder disk to its side, grind the holes and crevices in the casting until they are beveled.

4. Connect the welding ground to the casting metal to create a connection between the grounding lead and the welding stick. Weld a 1/2-inch bead along the crack, and allow it to sit for 5 minutes. Do not overheat the casting by welding too quickly; the welding heat could crack the casting. Mist water onto the weld with a misting bottle to keep the area cool.

5. Clean the weld with a chipping hammer and a wire brush. Make an additional weld pass along the crack, filling the crack completely with weld. Weld any holes or crevices with weld, making sure not to overheat the casting. Allow all welds to sit for 30 minutes.

6. Grind the welds down with the 4-inch right-angle grinder. Wear safety glass prior to grinding. Grind the welds with the flat surface of the grind disk. Slide the disk back and forth along the metal, and do not allow the grinding disk to sit in one place while rotating, which will damage the metal casting.

7. Check the metal after you have ground the welds smooth. Fill any remaining cracks and voids with small 1/4-inch weld passes to complete the repair. Grind them down until they're smooth.

References

• Welding, 2nd Edition; Don Geary and Rex Miller
• Welding: Principles and Applications; Larry F. Jeffus
• Welding for Dummies; Steven Robert Farnsworth