(d) over the pad a thermic insulating plate ( generally made of ceramics - item 2 in sketch )is placed to resist the weld heat to go to the pad (e) over the insulating plate a base plate of electrolytic copper ( item 3 in sketch ) is placed – the height of this copper plate should be such that it touches the bottom of weld assembly (f) put a mild steel insert (item 4 in sketch ) of approx dimension 3 mm height x 12 mm width (to put it comfortably in weld root gap x length equals to rail foot width.