You might try welding from the back. Try a few spot welds to see how it does. If seems OK, do a fillet weld made of spots. Don't need to grind the weld. If it fills in nice, bondo the front side to smooth out the radius. As Kevin says it must be cleaned down to bare with a wire wheel NOT a grinding disc. I assume you know the routine about warping.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
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