We are welding expanded,galvanized steel to galvanized angle iron using TIG welding. The zinc splatter mars the work. Can spot welding eliminate or reduce the splatter?

-- John E. Skvarla (fwdrw@inetww.com), February 16, 2003

Answers

Hello John,

With a well planned upslope, all the zinc splatter can be eliminated, but the resistance welding application may have a problem with the angle iron. If the angle iron is greater than 4 or 5 mm thickness, the resistance welder may not be able to handle it.

Another problem is that the sheet metal thickness ratios should not exceed 3 to 1, so thin metal to thick angle iron would be a problem. With very careful selection of tip contact surfaces, the 3 to 1 ratio can be stretched to 7 to 1, but this adds to the complexity of the application.

If you do fit within these limitations, then get a control that does BALANCED up slope (so the transformer doesn't go into saturation) or preheat, and experiment with the slope or preheat to melt the galvanized without welding it.

Once you have adjusted it to expose the bare metal on the facing surfaces, without welding it, (very important, you don't want to weld with the zinc caught in the middle, as it causes weak welds) then you can add your weld heat.

David Bacon

-- David Bacon (dbacon@updatetechnology.com), March 17, 2003.