I don't know for sure if they still use the same materials, but some of the Super Tigre and K&B pistons could be heat treated or normalized (or whatever term you feel is best ) in an ordinary kitchen oven...
Check out the Control Line Speed forums...there are some guys over there who could give us all some lessons on "Materials and Processes"...I'm not gonna drop any names here.

You can "grow" a piston by placing it in an oven at a certain temp for a specific amount of time. (I'm talking about some of the X 40 and 6.5 K&B pistons ) The pistions are then lapped to fit the ABC sleeves.

Agreed, the average "sport" flyer has no need to do this...basically they just wanna fly...but there is, IMO, no need to squelch a good thread. A discussion of model engine metalurgy is very interesting...again IMO.