How to Weld Cast Iron With an Arc Welder

Updated February 21, 2017

Welding is an important component of any metalwork job. Welding cast iron with an arc welder is a highly sought-after skill because of the shear strength of cast iron and its use in various projects. Cast iron welding projects range from fixing a broken heating pot to welding a crack on farm machinery. It can be highly valuable to learn because of the high costs associated with welding work. The cost for welding work ranges from £16-$50 an hour. Imaging doing it yourself to save money while learning a valuable trade.

Purchase or rent a SMAW (shielded metal arc welding or stick electrode) welder at your hardware store or equipment rental company.

Plug your welder into a 220V outlet and then plug in your ground cord and welder electrode holder cord into the welder.

Welding cast iron requires a special electrode. Purchase a 770 stick electrode to weld cast iron.

Clean the surface to be welded with a wire brush.

Clamp the grounding clamp cord from the welder onto the piece of cast iron to be welded.

Place an electrode into the welder electrode holder, position the electrode near where the weld will start and pull your helmet over your face.

Tap the electrode on the cast iron until it strikes an arc and begin to weave the electrode stick from side to side. Always keep the arc a half-centimetre or less away from the piece of steel you are welding.

Allow the weld to cool for a few minutes, then use the welding hammer to chip off the slag from the top of the weld.


If you ever run out of electrode and need to weld more, remember to chip off the slag coating before continuing to weld.


Safety first. Wear proper welding protective eye wear, leather gloves, long cotton clothing and work in a well-ventilated area to prevent fumes and gas build-up.

Things You'll Need

  • SMAW welder
  • Welding helmet
  • Safety clothing
  • Leather gloves
  • Wire brush
  • Welding hammer/pick
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