The Tinman Sayeth:

The sphere takes much skill and sweat to accomplish. The goal is for the metal guy to see the thing, know the field of operation, and then actually take hammer in hand and give all his theories a try.

As they say in the saltflats top end racing world: "Theoretical cars with theoretical engines racing on theoretical salt give theoretical results every time." 

I encourage metal students to try out their theories, and I keep the "concrete" physical item in front of them simply to intrigue and encourage, and also to keep them from scoffing it off as, "impossible". Read the ideas below before seeing how I did it at the bottom of the page.

Others say:

---Tinman,  Could you have possibly formed this around a steel sphere and then upon completion, drilled a hole through the titanium and heated it up and melted the steel sphere and drained it out through the hole. Titanium has a higher melting point than steel.  Just a wild guess!  TheSheet-fitters in Dutch Harbor

The Tinman says: NUP! DISTORTION, OXIDATION, and effort too much.

Others say:

---How even is the thickness of your famous ti-sphere?
What grade of Ti did you use?(some beta's warp very little)
Did you harden your ti sphere? 
Assuming that you cold worked. 
I think you cut out the shape of a globe, worked the metal as close as you could to a sphere around another sphere and welded it together. The heat from the last bit of weld would cause the air inside to expand and help the Titanium not to warp but to maintain a spherical shape. Then you polished and polished and polished.

---You drop a blob of molten titanium from a tower, that landed in a pool of oil and the inside cooled slower, the outside... 

---Ti powder heated in Ceramic hollow spherical cavity while rotating? 

---I guess you could form it around an existing sphere made of something you could then remove through a small hole. Maybe you could cut a pattern much like a baseball and form it as well. 

---I imagine that you spun or formed the two hemispheres and then welded and finished them. 

---Kent, I have been racking my brain on how this sphere was formed and I'm wondering if some type of a glassblowing technique was used. It seems to me that the shrinking of the piece would cause too much distortion in such a small radius. 

---You bought it LOL. 

---You say it's one piece. Is it really made from 12 pieces blanked out from the  flat, rolled, welded, and hammer formed to make one piece? I can't see how you  could make it from one piece of flat. If you did, you have too much time on  your hands! 

---My approach would be to use maybe two separate halves, but if the rules are a single sheet, I would use either of the following approaches:  A) Cut something like a jagged pumpkin smile and hammer it into two joined hemispheres in a bowl former, fold the two together and weld up the seams to form the rough sphere.  or B) Cut a sort of dumbbell shape with cross tabs in the middle.  The round end lobes would become the polar caps and the cross tabs could wrap around to form the central latitudes.  Again I would form the elements into spherical shapes in a hollowed out former and then bend them together to form the rough sphere by welding the seams.   Now the tricky bit of finishing:  I believe any heating of low spots will produce enough internal pressure to force them out and then you can quench the metal in the desired shape before the pressure drops off.  High spots can be hammered down after a little heating and quenched.  A little work with the heating / hammering / quenching process should get a pretty good sphere that could then be centerless ground between two sanding disks or some such to get the final surface.

And here is how Kent really did it! Drum rollllllllllllllll.......

Kent started out with a square piece of sheet metal and beat it into a sphere!!!