Shrinking Hammer

Whoever told you that is correct. They are not used on hot metal and they don't shrink by beating little dents into the panel. I have had to fix quite a few panels after "experts" beat the hell out of panels with the shrinking hammers only to make the problems much worse. Also, like Rotor said, when you hammer the metal against metal you are going to get the metal to stretch, making the problems worse. A small amount of heat, going slowly will achieve the best result. I have also tried the shrinking discs and they also work but I have not really mastered it.
 
Working metal is an art form. It takes a variable about of tools to be able to work different problems. A person can chase an oil can surface (stretched area) all around a panel if they don't know how to arrest it and make it disappear. A well prepared metal shaper will have all sorts of different hammers, dollies, slappers, and body files to aid in getting the desired shape into a project and those are just the basic hand tools of the trade. Making a flat surface round is a lot easier than making a round surface flat. I would suggest taking a look at some of the U-Tube videos about metal shaping or check out some of the metal shapers web-sites to get a good idea about what folks can do with the tools they have.

Many of the pioneers of metal shaping whether is was repousse' in copper, a silversmith making table ware, a carriage maker using iron or steel, or an aircraft cowling maker with aluminum, all had to do there job well enough that it could look just as good in bare form as in painted form.
 
I have small to medium sharp pointed dents in the flat portions on my pickup's bed sides from things banging around. I studied all of the shrinking methods and think I'm simply going to hole saw them out and weld new plugs.

Lonnie
 
On an extremely flat panel like that any imperfection will be very noticeable. I think cutting out holes and welding in plugs will make your problem worse. If it were me I would would (and have) try a shrinking disc after you knocked the high spots down a bit. You can always try your way later but you can never get that panel back to absolutely flat the way you are heading.Don't let it intimidate you. Best of luck- Dennis
 
roadster36 said:
On an extremely flat panel like that any imperfection will be very noticeable. I think cutting out holes and welding in plugs will make your problem worse. If it were me I would would (and have) try a shrinking disc after you knocked the high spots down a bit. You can always try your way later but you can never get that panel back to absolutely flat the way you are heading.Don't let it intimidate you. Best of luck- Dennis
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More to study then. Thanks!

Lonnie
 
In my experience a shrinking hammer used cold with a low crown dolly brings the metal up fast ,
 
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If you have sharp dents with holes pierced through, cracks, or rust through areas then you would be justified in welding in new metal to the affected areas if there was no better choice. For smoother dents, it would be easier to work them out that to weld in metal and have to work the warpage out of that. It's your choice but I would recommend the easiest plan of action. If you are going to use the truck then be prepared for more dents.
 
Low crown as in low curve .This hammer is not something I would use often .I use a bent file as a slap stick ,better for a large low crown panel .
 
Russ/40

I think you have given the best answer of all. I was taught when doing metal work that the purpose of the file was to show high spots not to file off metal. As to shrinking I was taught to hammer around the hotspot you create with a torch. And not to quench with water. As that quenching stops the heated molecules where they are and doesn't allow them to go back to where they were. Any comment on what I just said? In the past I had a metal man working for me that could spend hours on a Fender and make it look almost like new without losing much of the original metal. Sad to say he passed and I only received about 50% of his knowledge. My loss. I think that we are very lucky to be working on Ford's as they have super metal that was designed to last.
 
I've been told the same thing about quenching. Most of the metal Ford made was in a "draw quality" state for best results in forming the panels so it was relatively soft to begin with. Quenching puts a different temper in the little spot that was quenched but the rest of the panel will be on some different level of hardness. Heated spots left to cool on there own don't make near as much bond grain change in that area as when it is quenched. I like the idea of the shrinking disk. It heats the little high spots and burnishes all at the same time. This spreads the heating effect better and causes less overall tension in the molecules of the panel. It tends to normalize the panel better too so that relieves some of the stresses built up. I think that some folks get carried away with the quenching. It has its place but you have to understand what it's going to do when you do it. Some folks just use compressed air to cool a spot. It takes a lot of experience to get the feel for how a metal is going to respond to what you do to it. The best metal men generally not only know how to work the metal but also have a feel for the metallurgy in the material they are shaping. Each different metal responds differently and this knowledge is very important.
 
Great insight guys. When I was instructed on the heat shrinking technique I was first taught to not overheat the spot. Just below the level of a glow. Then hammer and dolly from the periphery to the center. Then quench slowly as you go, not with a soppy rag, but a damp one in circular fashion, working from the outside toward the center. I suppose this gradual cooling will allow for more normalized molecular states.
My current efforts are on the P/U bed, and I am also learning that the gauge of the metal there adds a whole batch of new considerations.
 
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