I'm a student of welding engineering at ohio state and someone claimed that they heard of a way to resistance seam weld a tapered casting in between 2 pieces of sheet metal.  I find that hard to believe seeing that the tapered piece has a varying thickness.  Not only would it be hard to control the heat, but wouldn't the part just squeeze right out from underneath the wheel electrodes?  My classmate said that he doesn't remember what the technique was.  I was just wondering if anyone has ever heard of a way to do this or if it's even possible.  Maybe I'm not looking at it the right way but the way I see it, let's say you have a rectangular piece of metal about a foot long or so, about 1/2" thick on one side and it gradually tapers down to 1/16" or something like that.  Then you have a piece of thin sheet metal on the top and bottom.  When I visualize that, I would imagine that the nugget would not form correctly because the wheel electrodes would not be properly lined up (due to the taper).  Even if there was a way to overcome that, how would you control the heat all the way down the taper to make a consistent weld.  I've never heard of anyone doing this before, and it would be interesting to find out if anyone has.  Thanks.

-Adam