my friend has but I havent personaly dont think it was too hard...he layered it with a lot of layers and spent along time waiting for glue to dry...but haha
after a month of building the thing with his dad and like a week after he finished.. hes like hey check how well I made the flex on this, starts hopping on it and it snaps in half we were like 12 and he ran inside all teary eyed, funny now looking back but I felt for him when it happend