If you can picture the shrinkage action the only upsetting that happens is
the red metal. The cool metal surrounding it is preventing the red from
expanding so it upsets/swells. When you cool that area around the red the
cooling metal fights the expanding red area increasing the upsetting. Once
the whole area is black the metal is cooling and contracting but the
shrinkage effect is lost..
I have bent one inch plate heating it to a red on one side and spraying air
/water mist at the same time on the other side. It will take a kink out
right fast.
Randy

"Eric R Snow" wrote in message
...
Randy,
When I learned this water was applied to the red area. And stuff
shrank right up. This is what I was taught: The red area, as it cools,
draws the metal in toward the cooled area. I will try your method
however, because it always pays to know as much as possible.
Thanks,