<VV> Friction Stir Welding (no specific Corvair)

[John Kepler]

  One piece was held solid while the other would spin using a motor and 
weighted holding fixture, when it reached a pre-set speed the motor power
would 
cut off and then the parts were forced together making the weld.
 Gene Barr

Actually, one of the first major applications of this type of welding was
used to make the op-rods in John Garand's M1 Rifle in WW II.  The stainless
steel "button"/piston on the 4140 alloy op-rod were friction-welded
together....the best way for dissimilar metals to be quickly and permanently
joined with no skilled labor required (the average worker at Springfield
Armory in 1943 was a 46 year-old grandmother working her first job outside
the home!).

John