I need to mount my front bumper for a 1947 plymouth coupe. The brackets don't fit the sub frame at all. I need to cut them in half and reposition the back half of the brackets. The question is: are bumper brackets to these older cars made of spring steel are just mild steel? Mild steel is ok to weld, but spring steel is not too good. The brackets are about 1/4" thick. Can't tell if the bending is just flexing. Has anyone tried this and had any bad reactions?