How much time does it take for a scaphoid fracture to appear on an x-ray ?

It depends: It depends how severe the fracture is and whether it is displaced or not. If the pain persists, especially when you touch the snuff box region( base of the thumb and carpal bones) repeat x ray in 7 to 10 days or MRI is recommended. Ulnar and radial stress AP x rays may also help reveal a nondisplaced scaphoid fracture.

Scaphoid fracture: Scaphoid fractures are occasionally difficult to see on x-ray. Sometimes you need advanced imaging (CT or MRI) is needed to diagnose occult scaphoid fractures.