In this article I will attempt to explore the stages needed to produce in quantity a metal toy soldier. Please note that these procedures may vary from manufacturer to manufacturer, but encompass what I think is the industry standard.

As all things, it is always best to start from the start, and in this case the start is what is known as a “Master”. This is a unique sculpture of a model in a very similar size to the size of the final product and it is known as one to one (or 1:1) as it identifies the proportions involved.

The master is sculpted (usually by someone talented) in a sculpting putty. There are several different putties available and each sculptor has his/her preferences both in general and for different occasions, but in general the most popular are epoxy putties like greenstuff or milliput and clay-like putties like sculpey.

Here are the differences and pros and cons for both:

Unless they are for smaller scales (<10mm), masters start with a wire core that is soldered together to form the skeleton of the model. Putty is then layered over the wire with each layer outlining more and more the final shape. The model is then finished by applying the final fine details and either left to dry or baked in an oven.

Once the master is done, the next stage is to produce several resin copies by encasing it in a plastic box and filling the box with a siliconic compound. Once the silicon has vulcanised (see below), the mould is cut and the master carefully extracted. This allows to fill the mould with resin (after sealing the cuts up with sticky tape) and to cast an almost perfect reproduction of the original. It is usually possible to cast between 10 and 15 times (depending on complexity of the piece), before the mould becomes un-usable.

Vulcanisation is a chemical process by which the silicon alters its structure to become considerably more elastic and rubbery, and because this is achieved at room temperature in a process that lasts roughly ½ a day, these moulds are usually called RTVs (Room Temperature Vulcanisation).

The resin copies obtained are then pressed in one half of a malleable rubber or silicon pizza shaped mould. Its state is comparable to play dough, this makes it easier to model the mould to make it follow the desired split line of the resins as only half will be buried in this half with the rest in the other half.

The split line of the model is extremely important as it is in the nature of casting metal that there will be some seepage where the 2 halves of the mould meet, or there might be mismatching of the 2 halves, this will result in a little step along the entirety of the split line of the model (more on this below), therefore experienced mould makers will engineer the split lines to be in the most un-intrusive details of the models as possible.

Once the model is encased in the 2 halves of the rubber/silicon mould, this is vulcanised in a machine that applies considerable heat and pressure on the mould. Next, after having removed the resins, an experienced mould maker will cut into the now rubber like mould, feed lines for the molten metal to travel in and vents that allow the metal to fill every nook and cranny. A little drill is sometimes used and these vents create those extra little sticks of metal hanging off a model that need to be cleaned off before painting. Lastly a hole is cut out of the upper half of the mould.

This newly prepared mould is inserted into a casting machine that spins the mould at a certain speed whilst molten metal is poured into the hole. The centrifugal forces involved push the metal in all the cavities forming the model. Most of the time, the first mould is prepared so that the first casting can be made out of tin. The tins then are used to make production moulds that will be filled by a metallic compound that is made with pewter and traces of silver amongst other metals. This compound varies from one producer to another.

 A note on quality

The quality of the castings decreases with the use of the mould, until the cavities are so distorted that the entire mould has to be disposed of. And whilst most manufacturers will be very careful not to send out bad models, it is inevitable that if a mould has been cast several times, the later castings will be worst than the initial ones, and therefore there might be a considerable difference in the models that actually reach your doorstep.

Another potential consequence of casting these moulds is what is known as “squashage”. A mould needs to be gripped and pressed whilst it spins, so that when the metal is poured in, it does not seep out of the gap between the 2 halves of the mould. However this pressure can cause the cavities to be slightly squashed. If this happens, when the metal is poured, it will result in a “squashed” version of the original.

On the other hand, if the pressure on the mould is not enough, the model will have lots of “flash”. This is a very thin layer of metal that forms in correspondence with the split line of the model and, if excessive, can be very difficult to clean.

But the worst effect of all, in case of not enough pressure, is what is known as “mismatch”. This happens when the 2 halves of the mould slightly get misaligned. This creates a step in correspondence with the split lines and it is extremely difficult to correct.