Shop Talk

Elegance Recreated | Repair or Replace | The Essence of Handmade | Metal Shaping Basics

Elegance Recreated

Judging from the number of e-mails I've been receiving from people with an interest in building a body using a "donor" car as a platform now would be a good time to write about what this whole process entails. In order to do this, some background history is necessary to gain a deeper understanding.

When the twentieth century dawned the modern automobile industry was in its infancy. The bodies which rode atop a rolling chassis were nothing more than horse drawn carriages with a steel sheathing replacing the common wooden paneling. In addition, steel mudguards or fenders were placed over the wheels so the occupants weren't covered with debris. Simple but effective. In short order the industry began to evolve. Driven by the needs of the motoring public demanding variety in styling and price, the coach building industry was forced to keep up or be left standing in the dust.

After W.W.I drew to a close the pent up demand of the European elite caused coach builders to scurry to meet their needs. In England, the Rolls Royce and Bentley power house provided the bulk of the rolling chassis's which the elite coveted. In France, it was Bugatti, Delahaye and Delage. And in Germany, Mercedes Benz was well... Mercedes Benz. All of these European manufacturers and to a lesser degree some American companies, relied upon the independent coach builder to supply bodies for their coveted chassis's.

Due to the ever changing tastes of a demanding clientele, virtually all coach building concerns employed an in house stylist and designer. This gave the customer the ability to pick and choose colors and textures as well as shapes and dimensions. This process was mostly transparent, but nonetheless difficult because the artisans and craftsmen which drove and powered these establishments often times possessed huge egos. The money collaborating with the egos produced sumptuous styling that in many cases can only be described as works of art on wheels. However, as beautiful as these cars were on the outside the method of construction had not changed since the automobile had charged onto the stage in earlier part of the century. That is until a growing interest in motorsport demanded that cars keep going ever faster. In order to quench the thirst for faster and better handling cars, the Corrozzeria of Europe devised a new method of construction coined Superleggera or super light. In this method, the heavy ash frame was replaced by a lightweight secondary structure or "super structure" fabricated of either aluminum or steel sheet which bolted or welded to the chassis. This method again quickly evolved, whereby the fabricated sheet structure was replaced with a bent tubular structure welded directly onto the chassis itself. Virtually every great sports racer of the 40's, 50's, and early 60's was built using this method. To this day, the fundamental premise of super light construction can be found on every car that rolls down the road.

Fast forward to 2013 and survey the last hundred years of custom coach building and it's easy to see that not much has changed. From tools to methodology to design, everything has to be kept simple because of very low volume production. However, because of its elegant simplicity, huge skill sets acquired over many, many years of practice combined with the vast amounts of time the practitioners of the craft require to achieve stellar results conspire to feed the beast of misinformation. So, that being said the act of creating a full scale working body from nothing more than a picture or sketch or even an idea is hugely challenging!

A paradox of manufacturing is, small scale operations with very low production volume requires workers with highly specialized skill sets, simple methodology and a very basic array of machinery and tooling. Manufacturers with high volume require highly specialized machinery, complex methodology and much less skilled work force.

In the former of the two models, time is the force that drives it. And so goes custom coach building.

The methodology used for body builds that come into my shop is no different from most other shops that I compete with. We begin by establishing what the customer's design criteria are. Does he want a stylized recreation of a classic? A recreation of a classic on a modern platform, or execution of a totally fresh idea? In cases of the former and latter, a choice has to be made on chassis and suspension dynamics based on targeted performance. After the decisions have been made and the plan finalized, we begin by laying out basic dimensions of the coach work in unison with the chosen platform. Then we address packaging needs; cockpit size, convertible top, trunk, engine bay etc. etc. Only after all this ground work has been laid do we actually begin the act of construction.

This phase begins with the building of a three dimensional pattern known as a "buck". After the buck is complete, work on the support structure begins. Frames are made, doors, trunk lid, hood and any other movable panels. Next the major bulk heads are mocked up fabricated and temporarily fastened in place. The last component in the construction of the super structure is the fabrication of all the body aperture frame work. In order to hold all these components structures in place while being assembled a fixturing system has to be built and designed in such a way as to allow it to be easily removed once everything is welded, bolted or riveted firmly in place.

Next up is the act of creating magic; the shaping of the exterior body skins. This operation is the most satisfying because the plan is coming to fruition and all the heavy lifting is beginning to pay off. Once all the panels are shaped, they are meticulously welded and planished before finally everything is hung in place on the super structure. Sounds easy, right?

The build process I just described can take anywhere from 1500-5000 man hours and, in some extreme cases, even more. If you haven't viewed the Delahaye slide show featured on this website now might be the time to do it if you're considering having custom coach work built.

Repair or Replace

Often times collectors/vintage racers are faced with the dilemma of deciding whether to re-body their newest vintage racecar or repair the existing sheet metal panels. If the car has a body made of aluminum it is almost always better to re-body than repair, with a few notable exceptions.

Aluminum, over time and use becomes work- hardened and brittle. In addition, the panels most likely have been repaired and straightened over the years; this also hastens the process of work-hardening. If the panels have been repaired, someone used a file to metal finish after the panels had been planished smooth. If done improperly this can shave .030 to .040 from the surface of a fender. Couple this with the fact that the substrate has corroded and absorbed forty plus years of road debris, brake dust etc. etc. it becomes virtually impossible to weld.

Taking all these points into consideration the decision to re-body becomes an easy one. However, there are some things that you should be on the look out for when you choose a shop and commence work. First, insist that the individual blanks, which are cut and shaped to make up a completed fender, are as close to the size and shape originally used. This guarantees that the seams are placed where the original coachbuilder had intended and, goes a long way towards assuring that the fender or roof section has the shape it was originally planned to have. Second, make sure all the proper fasteners are used. Never use a pop-rivet where a screw was or, a solid rivet in place of a screw. Third and most important, never ever tig weld body panels! If the shop insists on this method of welding they do not have the experience and know how to fabricate an aluminum body. Insist that you want the panels flame welded- end of discussion.

Now for the few notably exceptions. If you're the proud owner of a 59' Ferrari Tessta Rossa with a Fantuzzi body or a 36' Delahaye done by Fagoni And Folaschi you would not want to re-body unless the original is burned or battered beyond recognition or the body is missing altogether. These are cases where the notoriety and artistry of the original coachbuilders met or exceeded that of the manufacturer and should be preserved at all cost.

The Essence of Handmade

Recently there has been a resurgence of interest in "handmade" cars. The reason for this growing awareness can be attributed to the many shows seen on television highlighting shops and individuals building custom cars and motorcycles. Traditionally, when I think of handmade cars my mind conjures up the image of the great Carrozzerias of mid 20th century Europe. These companies and the artisan-craftsman they employed produced some of the most stunningly beautiful automobiles ever to roll on four wheels, using nothing more than rudimentary hand tools. Today, this is not often the case. What we are seeing now is often times vehicles which I would call "hand fitted". You could define hand fitted by saying that a person accumulates all the pieces necessary to do a build and then modifies them, some quite heavily and assembles them to form a completed car.

To best illustrate my point I will draw on the example of Lance Reventlow. In the mid 50's Lance was a young man in his twenty's who just by chance was heir to the Revlon fortune. Because of his circumstances, he found himself with unlimited time and resources to pursue his interest, one of which was motor racing. Lance being a California boy thru and thru knew there was only one choice when it came to American racecar builders, and that was Troutmann-Barnes racing. Armed with the design expertise of Ken Miles the team of Lance Reventlow, Dick Troutmann, and Tom Barnes were able to develop and build a chassis for his new American Special, which would come to be called the Scarab. Once the final design for the chassis was approved and work began Dick Troutman walked down the road to see his old pals at California Metal Shaping. With nothing more than sketches and rudimentary dimensions Emil Deidt and Company cranked out one of the most outrageously beautiful racecar bodies ever built, the rest is history.

In my mind all the individuals involved in the construction of the Scarab were artisans of the highest order. They were able to build one of the most successful competition cars of its generation using very basic hand tools and machinery. In their hands, the tools and equipment were brought to life and an Icon was born.

The Basics

To learn metal shaping it is best to start with a few basic tools such as a shot bag, a wooden bossing mallet and a large tree stump with a dish shape carved in the middle approximately 6" in diameter and 3" deep hollowed into the center. The log should be about 24" in diameter and height, (you can place the log on a pedestal to your desired working height). The hammer and shot bag can be purchased from a company such as U.S. Industrial Tool and Supply Co. or Eastwood. It is best to begin with hammers and shot bag because the beginner can better control the basic hand tools. You are now ready to start.

Select a piece of aluminum or steel about 15" in diameter. Now using the blunt end of the wooden bossing mallet and the hollowed shape in the top of the log you can begin shaping your panel. The tree stump is used to quickly bring shape into a panel so don't be shy about hitting it. Hammer a shape 3" in depth and 12" in diameter into the center of the circle. Now proceed to the shot bag and slowly work out any gross imperfections. When this is accomplished, return to your tree stump and using the flat part of the log surface, you can begin to shrink the outer 1-1/2" of the dish. The shrinking process is best described as a gathering procedure. You will notice that the outer portion is wrinkled while the center section has a somewhat "drawn" appearance. The inner section of the panel is stretched from the hammering while the unworked outer portion is showing a series of undulating "V's". What you will be trying to do is increase the thickness of the metal by forcing the little V's in against themselves. Lay the edge of the panel on the flat portion of the log so that the wrinkled portion loosely resembles an inverted vee. Take your rawhide or wooden mallet and strike the top of the vee with a quick blow; this will cause the metal to increase in thickness thereby shrinking the edge of the panel. With a little bit of practice you quickly learn how to stretch and shrink metal. Just remember to go slowly and try to think about what is happening to the metal with each blow of the hammer.

It is best to begin with these techniques because the novice can gain a real sense of accomplishment with a relatively small amount of expended energy. Remember to try to think of the metal as modeling clay because the two mediums react exactly the same way to applied mechanical energy.

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