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Bore Welding


Bore Welding is a welding process that reduces the diameter of a bore by adding 3-6mm of metal to the inside of a worn bore which can then be machined back to the correct size with the line boring process. Usually a pre-machining process is carried out, ideally 1-2mm deep to provide a clean metal surface for the welding process. The correct welding procedure should be used for each individual application. One option is to pad weld by hand the area that needs to be repaired. However, using the bore welding machine will result in a much more consistent weld with less chance of slag inclusion and imperfections. We can weld bores from as little as 40mm diameter and out past 500mm diameter.



  • Before setting up the bore welder, determine whether there are doubler plates (two plates welded together with the same hole through them). If there are doubler plates it is best to use a heating torch to burn the grease out from in between the plates as much as possible. This shouldn’t exceed the pre-heating temperature.
  • Set up the bore welding machine in a suitable position to be able to fine tune adjustments.
  • Pre-heat the bore to the correct specifications.
  • Make sure there is no wind affecting the work area as this will cause the weld to get porosity in it. Set up a shroud around the welding area to stop the wind.
  • Use the appropriate settings for that sized bore and commence welding.
  • Follow cooling procedure if required.
  • Allow to cool completely before machining.

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