What are models made of? Few words on technology

Formula143 Collector’s Guide

Part 1. Collector’s Basics

Part 2. Few words about technology. What are models made of?

Part 3. The Brands. What scale models are there and who makes them?

Part 4. The Market. How much do models cost and where to buy them?

Part 5. Photo Studio. How to make quality photos of scale models?

Part 6. Cabinets and display cases. How to exhibit scale models?

Modern car scale models are made of metal alloys or of polymer resins. The main technology for manufacturing metal models is injection molding using molds. Such models are called diecast. Resin models are also made by injection molding followed by polymerisation of the resin. Another type of material for the production of models is plastic, but it is used much less frequently.

Of course, with the help of casting, only a body of the model is produced. The further technological process involves priming the model, painting, applying decals, assembling with the addition of small parts (windshields, suspension parts, wheels, tires, etc.) from plastic, metal and rubber. We will not dwell on technological details, but briefly consider the main categories of models in relation to the material of manufacture and the company that produces such models.

I have 4 different types of models in my collection with regard to material – diecast, white metal, resin, plastic. As you can see from the diagram, 76% of the models are diecast, 15% are resin, 8% are white metal and 1% is plastic. Diecast, although it remains the most represented technology, is gradually giving way to resin.

Diecast. The casting technology of  scale models appeared 100 years ago – in the 20s of the XX century. The material used was an alloy of lead and tin, and then zinc-based alloys. From the 40s – 50s of the last century, the main material for cast models is Zamak – an alloy consisting of zinc, aluminum, copper and magnesium. Zinc is the basis of the alloy, aluminum is represented in the amount of 3.7 – 4.3 weight %, copper – up to 3%, magnesium – 0.2 – 0.6%. In different alloy standards, iron, lead, cadmium, antimony, and nickel may also be present in small amounts. Such an alloy has high strength and stability. In the manufacture of products by casting, the mold is filled under high pressure with molten alloy, then the model is cooled and removed from the mold. Diecast technology remains the main one for large-scale industrial production of models. In the segment of racing cars, almost all major manufacturing companies make their models using this technology. Among them are current market leaders (Minichamps, IXO, Brumm, Rio, Bburago) and many companies that have already ceased to exist (Onyx, Quartzo, Corgi Toys, Yaxon).

White metal. White metal models are also made using casting technology. The differences are in the composition of the alloy. White metal is tin-based alloys with the addition of antimony, copper and lead. Tin alloys usually have a light color – hence their name. Tin in white metal alloys ranges from 40 to 90 weight percent, lead – up to 50%, antimony – 3-10% and copper from 1.5 to 30%. Cadmium, bismuth, and zinc may also be present in some alloy embodiments. White metal is heavier and more fragile than Zamak. However, the white metal casting process does not require such high pressure and high temperatures as when working with zinc alloys. Therefore, white metal alloys are used mainly by small companies and workshops. The quality of white metal models is generally slightly lower than that of leaders making models from Zamak or resin. Often, white metal models are sold as kits — the base unpainted casting of the body and a set of additional small parts and decals. The higher cost of white metal models is due to the high cost of unit production, rather than higher quality. Among the manufacturers of ready models and kits made of white metal are Tameo Kits, Meri Kits, SMTS, CP Models, FDS Automodelli, Villa Models, etc.

Resin. Models of polymer resins are gradually occupying an increasing market share of scale models. The material used is epoxy, polyurethane, polyester or acrylic resins. The manufacturing technology of the model consists in casting the model in a mold, where liquid resin is poured with the addition of a polymerization catalyst. In the polymerization process, the resin hardens and forms a blank for the model. Resin molds are made of vulcanized silicone, latex rubber, or other similar materials. When resin models began appearing on the market in the late 1990s, many collectors doubted their durability and health safety. However, modern polymer resins do not have any problems with safety and durability. The quality of resin models is not lower (and often higher) that for a diecast in the same price segment. Casting from resin does not require high pressure and high temperatures, however models from resin are usually more expensive than diecast. The reasons are the rapid wear of molds, the higher cost of the material, and the high labor costs for producing models. The undisputed leader in the mass segment of resin models is Spark, the first of the major manufacturers to master this technology in the early 2000s. Other companies making polymer resin models include LookSmart, BBR, True Scale Miniatures, Autocult, Top Model Collection, Provence Moulage and others. Spark’s main competitor, Minichamps, has been slowly introducing 1:43 resin since 2004. Now the entire last line of Minichamps Formula 1 car models (starting around 2016) is made from resin. Some small firms and workshops specializing in the production of small series of hand built models also use resin.

Plastic. Plastic injection technology is also used to make scale models. The technology is similar to diecast, however, the material is not metal, but plastic. The molten polymer is injected into the injection mold under pressure and then cooled. The polymer used is usually polystyrene. Now the main niche of such technology is kits in other scales than 1:43, but some time ago some companies produced ready models from plastic in 1:43. In my collection, manufacturers of plastic models are represented by Minialux, Cursor and Igra – all of them belong to the category of vintage.

In the near future, plastic can get a second life thanks to 3D printing technology. Already, some workshops and individual modelers are trying to make scale models using 3D printing. The technology does not yet provide the quality and cost  comparable to diecast or resin. However, there is no doubt that in the future, 3D printing will be able to compete with current model production technologies.

Conclusion. Two main modern technologies for the production of scale models (diecast and resin) ensure high quality and durability of models produced by well-known brands. Therefore, when buying a model, it makes sense to focus not on the technology of its production, but on the value of the model for your collection. White metal models can be a complement to the collection, especially if they are not represented in the mass segment.