Cracks in hood ?

Good luck.

Drill a 1/8" (or a little larger) hole at the end of the crack. That'll usually stop the crack from spreading further. Grind open the two edges of the crack to open it up. Place a piece of clean steel on the underside to provide a backing plate. This can be any thickness, but not more than 1/8" or so. Stick, MIG, TIG or gas weld the crack. Start at the drilled hole but don't run all the way to the end of the crack. Stop about 1/4-1/2" from the end and let the metal cool. Clean up (grind) the last part of the seam and when cool, complete the weld. Grinding is still required to smooth the bead. You can also take a pick hammer and tap the area a little lower that the hood surface to provide an area for body filler. Alway hit the "body filler area" with a 32 or 40 grit sanding disc to provide a good anchor for the body filler. Then go from there with the standard body work process. The backing plate should not be used where it would be visible when the hood is installed. The plate provides a "heat-sink" and reduces distortion of the hood in way of the repair. I've also brazed these cracks with good success.