Quote Originally Posted by mactec54 View Post
How big is the inside form cup??

The pressure required will also have to be worked out, depending on the form size, this will determine the material you can use

There are people that are 3D printing plastic forms to make parts like this so you may be able to use anything for just a few parts
Total area for the cup is about 48 square inches but the stress limit on the plastic or whatever is used is PSI not total pressure. The pressure is also heavily dependent on the sharpness of the corners and the draw ratio as I understand it.For a trial run I am working on a part that is about 1/4 size with bend sizes of the full size part.