How i sculpt a giant face

I use different methods for sculpting my large faces. This one process uses an armature or understructure to build a form over.  This sculpting technique requires the use of an original form to work on. Most of the time I will have to build the underlying armature first. this form will be modeled to reflect the appearance of the mold that’s sculpted over it. In other words the sculpture i build over the top of the original form will look almost exactly like the original.
    Once i have the original all welded together i can then start  making a duplicate. In this case here i constructed a 10 ft tall mild steel fece from rusted scrap metal. I then laid the face down facing up and proceeded to weld a stainless steel duplicate over the top of it. I clamped the metal to the original to follow its form tightly and welded it together piece by piece.
   When it was complete i built a stainless steel frame for the duplicate sculpture to be supported by.  Here you can see the original displayed in a NY. Gallery and the stainless steel sculpture duplicate that was made from it. Sorry for the blurry image of the rusted one.