The Ford Barn

J Franklin · 04-04-2018, 11:45 AM

Shrink it as you would any metal you need to work.

Kevin in NJ · 04-04-2018, 02:23 PM

The physics is the same for all steel and well most metals.

When you heat up the metal past the plastic point the surrounding colder metal will put a pressure on the warmer atoms. These atoms at some point will be allowed to overlap themselves. When cooled the pressure holds them atoms in place as the temp drops below the plastic point. You have shrunk metal.
Now when you use a hammer and dolly you can cause a greater amount of overlap increasing the shrink amount.

A second way to shrink metal is to capture a wave in the metal and use a plastic hammer to flatten. The will also bring the metal into itself. I believe in the stronger stainless a bit of this can happen and that is why you can sometimes move the metal with careful hammer on dolly work.

To shrink the stainless and to anneal it a bit you just heat it up. You have to be careful to do small areas of heat. When trying to move large dents or working the dent a lot the annealing does seem to make the metal movement easier.

I suggest that you find the video 'Shrinking Magic' and watch it. There are also talks about the technical details on metal shrinking at metal working sites. Been a while since I went down that path and it seems to be grown over and my links are not good.

A final warning!!!!
Shrinking metal at the wrong times is very very very bad and make make repair of some curved surfaces almost impossible. Shrinking should be done in small amounts and you must allow the metal time to come to the same temp before you do further work. Heat shrinking is a last resort for an experience person. All others go with caution.
Some will tell you to shrink metal that the actual repair is to stretch metal. If you have welded on a panel and it is not right then it is more likely that you need to stretch the metal to correct the weld shrinkage.

04-04-2018, 11:45 AM	#21
J Franklin Senior Member Join Date: May 2010 Location: Oregon Posts: 5,963	Re: Removing dents from a 31 Radiator Shell Shrink it as you would any metal you need to work.

04-04-2018, 02:23 PM	#22
Kevin in NJ Senior Member Join Date: May 2010 Location: South East NJ Posts: 3,398	Re: Removing dents from a 31 Radiator Shell The physics is the same for all steel and well most metals. When you heat up the metal past the plastic point the surrounding colder metal will put a pressure on the warmer atoms. These atoms at some point will be allowed to overlap themselves. When cooled the pressure holds them atoms in place as the temp drops below the plastic point. You have shrunk metal. Now when you use a hammer and dolly you can cause a greater amount of overlap increasing the shrink amount. A second way to shrink metal is to capture a wave in the metal and use a plastic hammer to flatten. The will also bring the metal into itself. I believe in the stronger stainless a bit of this can happen and that is why you can sometimes move the metal with careful hammer on dolly work. To shrink the stainless and to anneal it a bit you just heat it up. You have to be careful to do small areas of heat. When trying to move large dents or working the dent a lot the annealing does seem to make the metal movement easier. I suggest that you find the video 'Shrinking Magic' and watch it. There are also talks about the technical details on metal shrinking at metal working sites. Been a while since I went down that path and it seems to be grown over and my links are not good. A final warning!!!! Shrinking metal at the wrong times is very very very bad and make make repair of some curved surfaces almost impossible. Shrinking should be done in small amounts and you must allow the metal time to come to the same temp before you do further work. Heat shrinking is a last resort for an experience person. All others go with caution. Some will tell you to shrink metal that the actual repair is to stretch metal. If you have welded on a panel and it is not right then it is more likely that you need to stretch the metal to correct the weld shrinkage.