How to Weld Outside Corners
In response to a viewer's request, Kevin explains and shows how to weld outside corners. This time, he's using 5/16" steel, because the viewer asked about welding 1/4" steel and that's as close as Kevin had in the scrap pile. First, he cuts the plate to size, then overlaps the corners a little. You don't want a gap and you don't want it flush, you want to have a space open where you can make your weld. Next, he jigs up the metal on his welding magnets. Then Kevin steps over to his Longevity MigWeld 250P to set it up. He mentions the helpful rule of thumb to set your welder to one amp per thousand of thickness as the place to start, then you can fine tune it from there. So he sets his voltage to 25 volts - as high as this welder will go - and his wire feed as high as it will go, which in this case is 311. As he notes, if your welder won't go that high, then welding steel this thick will be a problem .... Kevin puts on his helmet and tack welds the two pieces together on each end so he can pull the steel away from the magnets, which otherwise will affect the weld. Then he decides to turn down the voltage a bit to 24 and leaves the wire feed at 311. He welds one more tack in the middle, just to see if the voltage better. Then he welds from one end to the middle horizontally, and the other end to the middle vertically. You have to move a little more quickly when welding vertically, maybe weaving back and forth a bit, almost holding the puddle up to counteract gravity. The horizontal weld is almost flat, but the vertical weld is a little dished, perhaps because he may have gotten a little more penetration with that weld. He'd then normally come back and put another weld over the top of the whole corner so he could come back with the grinder and get a nice sharp edge, then come back one more time and just dress that edge to give it a clean 45" angle. Finally he recommends coming back and making a pass on the inside of the corner.
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