Thread: 55 Wagon Progress

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I refer to hammer welding as using a hammer and dolly on a weld while it is still hot, what I did here was to tack from one end to the other, and hammer and dolly after that round of tacks, so the weld was likely cool to the touch. When tacking you do sometimes find the panels trying to overlap as the last weld shrinks, but a hammer and dolly will stretch the weld tack back out a bit enough for the panels to align again and continue tacking. For those who have used the eastwood style butt weld clamps during welding, a weld on either side of the clamp will typically show how much panel movement is experienced from the heat of welding, as you may see the clamp locked in place as the panels shrink/move together.

I don't use brass or copper behind the panel, as I use welder setup to give me full penetration welds without them, so any "backer" would only serve to heat sink and affect that setup. Here's a sample, front and back sides showing the full penetration welds on a Fairlane trunk opening repair...








This was close enough to the adjacent bend detail that it held most of the weld shrinking issues in check, so I waited until after all welding complete to planish the welds...

Further, if using a backer and it is not tight to the back side of the panel each and every time, then you are affecting the amount of "heat sink factor" for the possibility of affecting the weld consistency from one to the next. While I agree that people should use what gives them the best results, those methods, however performed, should promote consistency.