Originally Posted by Ripped
I have been working with the shrinking disc.
Things are going okay, and I am learning.
What I was wondering; If I quench the metal on the reverse side, will it shrink out? or do I need to stretch the metal with a hammer and dolly?
Shrinking is just shrinking. Which side you cool doesn't matter. It will go in or out depending on the shape you're working with.. But the key is the change in surface area you're talking about.
How much of a dent are we talking? If it's very shallow, there could be a low spot because the metal is over-shrunk, or because it's stretched. Can you push it from behind and have it pop out into a bump, then go back like an "oil can"?
If so, i'd guess it probably needs more shrinking. If you can't push it back out, it may be overshrunk and need to be worked on dolly to stretch it a bit. But don't do that until you're sure that that is what it needs.
A little light sanding with some sandpaper on a flat block can show what's going on, by highlighting high areas. A stretched dent will look different, it will have a high ring around it. A shrinking disk would fix that right up.
Photos might help.