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How to Repair Cracked Diecast Metal Trains

The best way to repair a diecast metal train that has developed a crack is to solder the crack closed. Because diecast metal is relatively light and ductile, attempting to weld the crack closed with a MIG welder would probably damage details on the train. Although bronzing could be done, the torch necessary for the bronzing work could overwhelm the work area.

Things You'll Need

Soldering flux
Soldering gun or iron
Solder wire
Sandpaper
Touch-up paint

Instructions

- 1
  Position the train so that you can easily work on the crack directly from above, and then clean the crack thoroughly with sandpaper. If the crack is particularly small, you can use an emery board to clean away the paint on the metal's surface.
- 2
  Open the canister of soldering flux near the soldering gun. Plug in the soldering gun and allow it to reach its maximum temperature before using it.
- 3
  Press the tip of the soldering gun against the crack in the diecast metal. This will slightly warm that part of the train and will make the solder adhere to the metal more easily. Unroll a few inches of the soldering wire.
- 4
  Dip the tip of the soldering iron into the soldering flux, and then press it against the crack in the train. Push the soldering wire against the heated soldering iron. And after a few moments, it will begin to turn to liquid.
- 5
  Manipulate the molten solder into the crack by pushing the wire against the soldering iron so that it bulbs up and flows off the tip of the iron and into the crack. Once the crack is filled with solder, let the patch cool while you unplug the soldering iron and cap the flux.
- 6
  Sand the patch so that it becomes even with the surrounding material. Then complete the repair by painting the repair area with touch-up paints that match the surrounding colors.

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