there is no mold.....
they use wood patterns.....they call them 'bucks'
here are the heros of metalwork
California Metal Shaping....
they had my Dad's ERCO shrinker for years
I asked my Dad to show me how to work on a shot bag.....in 15 minutes he roughed out an alloy tank for a Kawasaki i was building
then he put the wooden hammer down and said "I don't want to do this, its going backwards......you figure it out" and walked away
Gee, thanks Dad, its a dying art and you were one of the wizards and you won't show your own son?
the Northrup Alpha hanging in the Smithsonian
my Dad did the wing root fillets......one piece of metal, starts at the rear and wraps ALL the way around the wing NO grinding, filing or sanding ALLOWED
look how crooked the tail surfaces are......then look at the light reflections off the wing root....yes, perfect
he made the original gas tanks too with sine wave seams so they won't crack......the plane is missing them and its ID tag......I have a blank one, fuck them
TWA was too cheap to give him a pass to go work on their plane......
that is not the original configuration of the plane......i have the pictures of every iteration of the plane......
and one of it on its test flight with my Dad's buddy flying it.......and they don't even know his name