Die cast model car design is a unique and wonderful skill to have as part of my experience. But there is no school or technical education that teaches this specialty. Die cast models are very different from other types of models because they are a complex combination of materials and involve a great deal of manufacturing knowledge in order to get them to look, feel, and sit just right.

This short article is about some of the rather less known aspects of how these miniature models are replicated and some of the special tricks that I have used to help me design and develop these models with the talented teams of design and engineers that ultimately build these fine models.

To begin with, let’s look at scale. The process of scaling down a car is not a linear projection. If you were to take a full sized car and reduce it down to 1:24 the original size, several of the trim and detail features would simply vanish to the naked eye. So the pattern must be adjusted in several areas to accommodate the shift in scale. To do this, an average of the profile is studied and the key elements are maintained as true to size. The trim or chrome molding is enlarged, as are the body creases, fillets, and often times, even the radii of curves are reduced in an effort to give the illusion of a full sized car. For those of you who are audiophiles, think of the scaling process much like you would use an equalizer to modify the sound or certain performances in order to enhance the symphonic experience, or mimic a large concert hall.

Building the body master in scale for a familiar car is a challenge. The car is familiar to everyone who sees it and so the familiarity MUST be consistent. It is like seeing an old friend. If they change too much, you might pass them by in a crowd. The same is true with familiar car shapes. They have to be as close to the original design as possible. When reviewing a car model, it is on top of a table and you see it as a whole. No one sees full sized cars this way, so I use a reducing glass (the opposite of a magnifying glass) to help me see the car further away from me and more like a large car would appear in the distance. I also hold the car up to the mirror after spending an hour or two reviewing it. The mirror image changes the patterning of recognition in my brain that I have established due to familiarity and I see things in a new light. This always helps me catch a few last minute details.

Engines are tricky business when it comes to scale. In a muscle car, people forget that the engine bay for most cars built at the peak of the muscle era where HUGE. As a result, a standard 350 engine can look darn near anemic in a stock engine bay. I often will “cheat up” the engine scale by as much as 20% in overall size to help assure a nice fit or appearance of fit. People rely a lot on relative perception. A friend of mine runs a pizza and pasta shop and all his past plates are small ovals. They pile the pasta on the plate as though it were overflowing. It makes the dinner guest think they are getting a lot of food for the money. A bigger plate with the same amount of pasta won’t have the same effect. Same thing is true for tires. Tires were not so wide back in the years of bias ply. I scale the thickness of tires up just a bit now and then to give the illusion of fat and wide muscle car-ness that goes with the nostalgic memory of the cars mystique, not always the reality.

Texture and contrast are two of the most critical aspects of creating a well-detailed model. The best way to judge a high-end model is to look at the wheels. Designer Raymond Loewy said, “Wheels are 90% of a cars design”. Now I wouldn’t go that far but the point is that they are important to the cars looks. Wheels have several textures, chrome, paint, color insignias, various finishes etc. A well-detailed Rallye wheel can have six or seven detail specs in order to make it appear correct. Under the hood, using three or four types of silver or two different levels of texture next to each other add a great deal to the appearance of depth and value.

Textures must also be scaled within the correct framework. I also will use my reducing scale to help me determine the correct percentage reduction. There are standard types of textures that are used in mold making and they come in a handy book or sample textures that show all the patterns in 100%. I generally eyeball the % reduction I want to use, depending on what I see in the actual car. George Bojaciuk had one vendor actually create a graduated scale of texture reductions to help keep communication clear. Great tools are part of how we do our jobs, but the best tool is clear and concise communication.

Building these cars is challenge enough. But imagine that you have to assemble something you have never seen before, in a scale reduction, presented to an audience that is expert in the appearance and combination of details it represents, and do it all so that thousands can be remade in a reliable and consistent fashion. Oh yes, I forgot, and the instruction manuals don’t exist, but you can ask all the questions you want only using language that is not native to you and getting answers back in the same language. Oh wait I also forgot, you have to do it under deadline and within cost constraints….well you get the picture. It is far more complex and involved a process that many people think. But the key is the right kind of communication.

Clear terms with specifics are key:
- Use PMS 874 gold, NOT 873 on part #135 (distributor cap)
- Reduce thickness of brake pedal by 1.5mm

All models are designed for “stacking” or “layering” when in production. The stacking refers to the way a model is assembled together and the way it stacks as the parts are combined in assembly. It takes a very clever person to configure the assembly of a model while it is going down a production line. Parts must come together easily and with the least potential for damage while they are being glued or screwed in place. Stacking also contributes significantly to increased ride height as washers, screws, floor, chassis, and trims are all loading up together to build the model. Sometimes, the material thickness is at the very minimum it can be, but the model still stacks too tall. Shaving parts does not always do it and lowering axles on adjustable or working suspension can be a nightmare. Studying the assembly of a model at the prototype phase is important for this aspect and is not often a shared responsibility of the designer and the engineer.

Here are some other tricks of the trade that I use to help me along the way:

Graphics don’t always scale down exactly so I use the real car graphics kits and then use the scaled down measurements to match the actual stripes or logos.

Count! Amazing how a simple thing like this can be so helpful. I count seat pleats, bolt heads, chassis line details, grille bars, valve cover ribs etc. It helps to scale things down as well but it also keeps you honest. You would be surprised how many letters I got while at FM telling me that people had counted items on the car.

The best model cars start out with the best reference. Because a picture is worth a thousand words, make sure the picture tells the story with the least amount of confusion or doubt. Make sure the car is original and correct but also take out anything that is not real. I had photos of a license plate frame in the back window package tray on the Mini Cooper. The prototype had this detail molded in! How do they know it is not supposed to be there? This might be an exaggeration but things like extra exhaust clamps or flex hoses often don’t get caught early on and they can really make a car look poorly done,

Experiment on things. Try new textures and devices for creating different aspects of finishes and textures on models. When I started the Old Reliable Truck for FM we had done several rounds of trials with the factory and it was coming along well, but it wasn’t until George B. took the truck and “messed it up” with his own modeling hands that it started to gain character.

Passion is what makes a good model GREAT. I think if you love what you are building, it comes together and forms a unique and gratifying whole. Mechanical and technical experience aside, every now and then some models come together and shine better than others. They seem to have more soul than other models. I think some of my models like the 300SL roadster, the Bugatti Gran Prix car, and the Agajanian special (which GB finished off for me) are good examples of cars that hold together well and appear to have a soul. Roger’s Bentley Franay and his Green Silver Ghost are two good examples as well. Cars that model into another level like this have something to do with the passion you put into them. Danbury has done many models over the years but some of the best ones are the models that have been done by people who LOVE them. You can tell when you see them (mostly the pro- street cars) that the person they hired to do these cars has a passion for cars and modeling. Like any great product, the end result is almost always the combination of experience and passion. When you love what you do, it is not work, it is fulfillment of your drive to get it right.

RMdesign
Raffi Minasian
2715 Lariat Lane
Walnut Creek, CA 94596