How To Weld Coat Galvanized Sheet Metal

Welding galvanized steel is a dangerous task since the galvanized zinc coating on the metal becomes extremely toxic when it s heated.

How to weld coat galvanized sheet metal.

Take the proper safety precautions by wearing a welding mask a good welding respirator gloves and an apron. The best way to weld galvanized steel regardless of welding process is to remove the zinc coating from the joint. Don t attempt to weld thin materials like sheet metal with flux cored wires which put more heat into the base metal. If you attempt to weld galvanized steel without removing the galvanizing from the weld area the weld puddle will pop blow out and create a health hazard to the welder and any individuals in the immediate area.

In some cases the latter is done regardless of whether or not the coating was removed prior to. For example i worked for a while welding big tables that held furniture stripper chemicals. Welding galvanized steel is an important and valuable technique in the metal fabrication process especially when producing galvanized steel wire cloth or galvanized steel gratings but people are shying away from it lately due to the toxic fumes that welding galvanized steel produces. It depends on what you are welding and how critical the application.

When galvanized steel is arc welded the heat of the welding arc vaporizes the zinc coating in the weld area. Welding of zinc coated steel can be done but specific precautions should be taken. This results from the variation in boiling points between zinc lower and steel. This adds two operations.

You are right about removing galvanized coatings sort of. The continuous hot dip or zinc coated sheet comes in eight classes based on the thickness of the zinc coating. To weld sheet metal with solid wires use electrode positive ep or reverse polarity. Galvanized steel welds similar to uncoated carbon steel when properly prepped.

The sheet metal can be welded without removal and with a little damage to the zinc coating. In general the galvanized coatings after fabrication are thicker than the recommended amount and become critical to weld. Forget the larger 1 8 inch tungsten electrode and use a smaller one. Removing the coating and re spraying or painting the weld seam after welding to regain corrosion resistance.

Proper precaution is needed when handling these coated metals as their fumes can lead to serious conditions like the metal fume fever. We just welded em. Welding tips and tricks answer.