oh oh wait I want to play too! LOL
1. select a vertex at the center of a cap
2. ctrl-LMB and select To Faces (this selects all the faces on the cap)
3. shift-RMB and select extrude and extrude all the faces inward
... Bob's your uncle ...
you now not only have a new inner loop but the faces can now be extruded inward by simply pressing g to repeat the extrude.
https://youtu.be/d8WL4qnm128
"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675
Last edited by ctbram; 03-02-2012 at 03:37 AM.