Several weeks ago, I was very fortunate to obtain work experience at a local animation studio, helping out on an unannounced stop-motion production. Whilst I cannot at this time go into detail about the project itself, I can document the skills I develop and learn throughout my time at work, which will undoubtedly come in useful with regards to my SS1 project. In fact, the techniques I have witnessed, and in some cases implemented so far, are ones that I shall be using myself soon. Primary learning such as this is invaluable, especially in gaining the full picture of the production processes. All too often, when learning via online sources and books, certain stages are glossed over or even skipped completely, leading to much confusion.
Stop-motion, unlike the other forms of animation, is tangible- and as a result, there is no singular method when it comes to model fabrication. This is why it is so imperative to learn through experience and practice, such that we may eventually develop our own techniques and perfect our working practices.
One of my first tasks was to press mould Plasticine to create replacement mouths for the protagonist character puppet. Firstly, the Plasticine must be heated until it is soft and pliable. Plasticine is easier to manipulate the softer it becomes, a point especially important when press moulding, for it poses surprising resistance and does not compress as easy as you would expect.
The mould that I have been working with is made of resin. I am informed that the material is durable and long-lasting, and that you can expect to get close to a thousand models from it before it beings to deteriorate and lose quality. The resin can be expensive however, and as such it is not that practical for use by students who are working to a tight budget. As an alternative, I was recommended using Plaster of Paris, which despite only lasting for a hundred or so casts should be more than good enough for the limited use intended with regards to my project.
The mould halves are prepared with cling film, which prevents the Plasticine from sticking and provides an easy way to remove the material once it has been pressed. Plasticine is then added to the mould. Initially, the amount to use can be tricky to judge. If too much is used, the mould will not clamp shut properly, resulting in a mouth too thick to use. Conversely if too little is added, the model will have gaps and not be the correct shape. This process is deceptively quite tricky to get the hang of, for it takes a while to grow accustomed to the correct amount of Plasticine required. An added issue is that the cling film can crinkle and become embedded in the model if it is not pulled taut enough before the Plasticine is added.
Generally, I have found that adding a little less than you would expect is better. For my first few attempts, I added a level amount of Plasticine to each half. Whilst this did most certainly help in gauging the level of Plasticine required, it proved to be an ineffective method, as often the two halves were not ultimately sealed together and came apart.
It will take time to get used to any particular mould, and no doubt when it comes to creating my own, it will be a while before I start using the correct amount each time. It is always possible to add/remove some Plasticine as required, then place an unsuccessful piece back into the mould a second time- but taking multiple attempts to create a single replacement part is not efficient. I am told that professionals in the industry would typically mould one piece every twenty minutes or so.
Once the mouths have been pressed with the mould closing completely, ensuring that they are all the same thickness, they are removed from the mould and cleaned up. A scalpel was used to trim off the excess material, and the seam was then smoothed over by hand. The result of this process is effectively a kind of template- a repeatable default shape, upon which individual mouth expressions can be manually sculpted.
Plasticine is a very viable material to use in this manner. It is readily available, does not require a mould to be sealed as a liquid would, and the cast model can be touched up afterwards to remove any imperfections as a result of the moulding process. Furthermore, especially for replacement mouths, the models created are pliable, and can easily be manipulated to form in-between frames aside from key expressions.
Despite the time it has taken me to adapt to this new process, the whole experience has been very beneficial. This is, after all, what work experience is for! I know now what to expect, having experienced industry standard practices, used by Aardman Animations in Bristol, among others.
Making press moulds
Press moulds are a staple of replacement animation (unless 3D printers are being used), for they enable the relatively mass production of identical component parts. The process of creating a mould, based upon an initial sculpt, is one that has remained largely unchanged over the years, though new materials are making the process more effective.
Whilst at work experience recently, I had the opportunity to witness first hand the creation of a press mould- a process that I shall need to reenact myself for my SS1 project shortly. I was able to photograph the process at various different stages, so that I have a strong primary account to learn from.
The material pictured above right is ‘foamcore’, which can be purchased from many craft retailers such as Hobbycraft. It is similar to foamboard, but has a denser core layer which should be stronger. Nevertheless, either is fine for making a container for the liquid mould material to be poured into.
A benefit of these materials is that they can be scored and folded into shape from a basic net, as opposed to each side being separate and fixed together with tape or glue. This method reduces the amount of gaps where liquid can escape from, increasing the chance of success.
The mould ‘box’ needs a firm base- in this case, a spare piece of MDF was used. The tricky part of mould making is that it requires a certain degree of forethought, in that the mould half that you must sculpt manually needs to be inverted. The liquid will be poured on top, and will effectively form the shape of the air above the sculpted base. Any pegs you wish to add for alignment therefore need to be carved out, indented. From research online, I have found that people often use marbles, pressed into the clay, as a means of alignment.
For this mould the base shape was formed from clay, making sure that any gaps around the edge of the foamcore were closed.
It is up to the model maker to build up the base and pour in the mould mixture, judging where the seam line should be on the model. In addition to foamboard/foamcore, the container could be an old tub or box, or you could construct your own with wood, card or even Lego.
With the clay base sculpted and smoothened, the foamcore surround was fixed in place with a glue gun- sealing around the base and along any scored seams as a precaution. You can see in the images above that the replacement Plasticine component (that the mould will ultimately replicate) has been pressed into the clay, and any gaps around its edges have been carefully sealed with clay.
When the mould set-up was complete, it was sprayed with ‘Ease Release’, which prevents the liquid mould mixture from sticking to the clay or Plasticine. Alternatively, Vaseline could be used, though the spray is much easier.
The next part of the process was to prepare the resin- a two-part mixture which reacts and solidifies when combined (pictured below).
This particular mix required a ratio of 20% part A with 80% part B for any given amount. This means it is crucial to know how much you need to mix before hand, since adding any extra will change the ratio between the two chemicals.
Since the ratio of parts A and B is dependent on the overall mass of resin needed, the two parts were mixed atop a set of scales, calibrated such that the mass of the mixing cup was not counted. With the mixture complete, it was poured evenly into the foamboard surround. It is important to pour a small stream of liquid from as high as possible, to eliminate air bubbles from the mould.
The two-part resin mixture solidifies within a few hours, though it is best to allow a bit of extra time just to be safe. It actually becomes quite warm, no doubt due to the chemical reaction taking place within. Once the resin has set, the soft clay was removed, revealing the first half of the mould. I was asked to clean up the mould, carefully wiping away any remains of clay still stuck to the resin and Plasticine (below right).
In addition to helping out with the moulding and casting processes outlined previously, I have also lent some assistance with the construction of a set from wooden components. My jobs here were to make sure everything remained steady whilst the parts were drilled/screwed together, and to clear the accumulation of sawdust, which can drastically reduce the visibility of markings, thus hampering the accuracy of a cut.
From this, I have gained experience and knowledge relating to the standard procedures for set construction in the stop-motion industry, notably in the creation of a layered base allowing access underneath a set to add screw tie-downs for puppets.