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"By the Book" Sheet Metal Repair

"By the Book" Sheet Metal Repair
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Some people think that repairing automotive sheet metal takes natural talent. Others think the skills needed to bump out a dent, shrink metal or weld two panels together can be taught. Robert L. Sargent was one of these men.

Sargent was a teacher and writer who believed that the primary element of all skills is knowledge. “The man who understands the technical reasons why a job should be done in a certain manner is well on his way to learning to do it,” Sargent wrote. “Skill is the inevitable result of coupling knowledge and normal manual dexterity with diligent practice.” Sargent believed that all students had the necessary manual dexterity to fix rust or collision damage, but he knew that only a small percentage of them would practice enough to develop real skill.

In 1961, Sargent wrote a masterful book called Automobile Sheet Metal Repair that was published by the Chilton Book Co., of Radnor, Pa. ASMR became a text book for many high school auto body classes. Sargent put out a second edition of the book in 1969. Twelve years later, a third and last edition was published. Hot Rod Hotline contributor “Tex” Smith turned me onto this book. If you dream of building a hot rod, this is a book you really need to own.

A quick scan of the Internet indicates that the earlier editions of the book are hard to get. Most likely, this is not due to rarity, as ASMR was a textbook that was printed in large numbers. It’s more likely that the older copies of Automobile Sheet Metal Repair fell apart from all the use they got. The 1981 edition is readily available through Amazon’s used book service from prices of $1.85 up.

We can only guess that the book was not reprinted more recently because newer cars are repaired differently. Dents are no longer bumped out of metal and the lead fillers that Sargent wrote about are a thing of the past. To some degree, welding techniques have changed, too. And in many cases, damaged body panels are replaced, rather than repaired. On top of all this, many once-metal parts have been replaced by fiberglass or plastic components.

None of this matters if you are into building hot rods the old school way. If you’re working on a pre-war or early post-war car and doing body work, you should probably find a copy of Sargent’s book. If you spend more than average amounts of time in the garage, you may want to keep a second copy there. 

ASMR starts with a chapter on steel and automotive sheet metal parts. It talks about the make up and characteristic of metal, basic shapes of metal and ways to reinforce it, like crowning and flanging. Chapter two covers collision damage—the effect of force on the shape of metal and variables in a car crash.

A big part of Sargent’s teaching revolved around tools. He covers bumping hammers, dolly blocks, bumping spoons, body spoons, pry or pick tools, caulking tools and screw-equipped slide hammers. He then tells how to use each type of tool for basic metal straightening operations.

Metal shrinking fills another chapter. “Shrinking metal is simply a matter of making an upset where needed,” Sargent explained. “It is exactly the opposite of stretching (and) may be needed on any spot on any panel where it is necessary to reduce surface area to restore the proper contour.” In auto bodywork, shrinking involves using heat to soften metal to make the necessary upset. He tells how to use shrinking to eliminate stretches, gouges and low or high spots.

The book has a chapter on oxy-acetylene welding, fusion welding, brazing and electric-arc welding. Sargent does not get into the MIG or TIG systems used today. He covers resistance spot welding. Chapter 6 is entirely about lead body filler. Today, few shops use lead, but it is still considered the proper way to build an old school car. Many hot rodders would like to learn the techniques involved.

Chapter 7 covers metal straightening techniques and procedures, as well as the equipment needed to do the job. Body jacks and portable frame machines were high-tech devices when the book was written. Both are described in detail.

The book’s final chapters address hands-on training procedures designed to teach students how to do repairs and how to practice skills. Chapter 8 covers repairs to dented panels, buckled or crushed fenders, a hood, a lower door panel, a roof (including alignment procedures) and a frame. Chapter 9 teaches how to practice hammer and dolly skills, as well as body file, pick hammer and  disc sander use. Metal shrinking and solder filling are covered. Practice on straightening simple dents in scrap panels is also taught in Sargent’s book.


Brian Limberg of the Tin Man’s Garage is one of several experts offering workshops to teach sheet metal fabrication. 

 

Robert L.Sargent’s classic book Automobile Sheet Metal Repair is a must read for anyone contemplating old school bodywork.

 

A hammer and dolly are preferred body repair tools at L’Car, a Wisconsin shop that builds hot rods and restores classics.

 

Sargent’s book teaches the welding techniques that Mark Siedler is using to do a Model A top chop.