There are many ways to shrink.
How to shrink sheet metal with hammer and dolly.
Put your dolly behind the metal use your shrinking hammer and smack the metal using the dolly to absorb the impact and accept the rebound.
Start by inserting the fork into the edge of the sheet metal at the desired depth of the shrink you want to make.
To shrink stretched metal you need a wood hammer a dolly a torch and a wet rag.
Then twist the handle of the tool to twist the metal around one side of the fork.
First use your shrinking hammer and see what you can do to tighten up the metal with that.
Using a rosebud torch tip heat the center of the metal to be shrunk.
Then remove the tool and move it over so the fork will roll the metal over the other side of the fork by twisting the metal the other direction.
Use a permanent marker to mark the area you need to shrink this is critical as once you get going you can easily lose the spot.
You are looking for a nipple to form in the center.
Using hand tools and machines.
I have identified 14 distinct ways to shrink.
The idea was that if the hammered metal went up it was being stretched and if it went down it had shrunk.
Using care and finesse he then begins to tap the metal from the other side using the hard steel dolly as a backing plate for the hammer blows.
This is where the tuck shrinking fork from a few weeks back comes into play.
You have to adjust your mind to the concept that when you hammer on sheet metal with a steel hammer onto a steel dolly or anvil that you will expand or increase the surface area by thinning the metal.
Very important do not let the dolly rebound onto the metal.