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How to Mend Metal With Brazing

Mending metal is a difficult job and requires a more permanent bond than glues or screws can provide. Instead, the task calls for a method called brazing -- joining metals with heat.

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  • Time

    Under Half Day

  • Price Range

    $500 - $1,000

  • Difficulty

    Moderate to Hard


Step 1: Clean the Joints, and Clamp the Pieces

Clean the joints of the metal with a wire brush, grinder or abrasive paper. A dirty surface cannot be properly brazed.

Clamp the pieces to be joined together. For the strongest bond, make the gap in the seam as small as possible. (The pieces will be too hot to touch once they're heated, so do not try to adjust them.)

clean joints of metal with an abrasive

Step 2: Adjust the Torch, and Heat the Joint

Put on gloves and goggles before turning on the torch. Adjust the torch so that it emits only a small flame (Image 1).

Hold the torch about 1" away from the metal joint to heat it (Image 2).

Step 3: Apply Flux

After a few seconds of heating the joint, use a flux rod to sprinkle flux over the joint. The flux will remove the oxides on the metal.

use flux rod to sprinkle flux over joint

Step 4: Continue Heating the Joint

Remove the flux rod and continue heating the joint, moving the torch in a circular or zigzag motion. When the metal reaches the proper temperature, the flame will glow a dull red color.

Touch the flux rod to the joint again, and direct the flame ahead of the melting rod tip.

Step 5: Mold the Pieces Together

Continue heating the joint evenly and depositing flux until the two pieces mold together.

After the metal cools, chip off the excess hardened flux.