For much of my early work, I used Plasticine (faces, hands, feet, shoes, any living or organic-looking surface). Later, I came to enjoy working with polymer “clays”, i.e., malleable polymer plastics. The most readily available of these in Norway is Fimo Soft. You may find others in hobby or art supply stores, but a couple of these can make work very difficult and troublesome due to bad texture and really unattractive sculpting properties.
I will avoid naming any of these, but one very commonly sold such product will make most young and fledgling, enthusiastic artists grow sour with frustration.
If you want to buy Fimo, ask for fresh and short-shelved packs, as this material is supposed to be exactly as SOFT as the name suggests, and the material hardens during months of storage.
Fimo comes in a number of different colours; I prefer the white one, but sometimes I also use the skin-coloured variety.
The reason for this pitifully limited attitude to colour is that I often simply need to make a uniformly coloured maquette, in which case white is just right for me.
If I make a human or semi- human character, only the head, hands, and sometimes feet will need to be sculpted in Fimo; the rest of the character probably will have parts made from other materials. Therefore, skin colour will often be just right, too, as a base for further skin-like paint elaborations.
Additionally, Fimo can be painted in any acrylic or latex colour.
Any sculpture made from polymer or other plastic "clay" materials should have an armature inside, since a piece bigger than a few cm without something to hold it up will most likely collapse before it is finished.
It is not difficult to make armatures from steel wire and attached pieces of polystyrene.
Use a very soft and porous white type of polystyrene. In Norway, this is marketed under the name Styropor, as well as a couple of other brand names.
This white polystyrene will not make your piece crack upon heating in the oven; the harder lilac, blue or yellow ones will, since they take more time to shrink during heating than the polymer does.
These somewhat harder polystyrenes can be very useful for other work, such as making backdrops for your creatures, for quickly making lightweight elements like props, or for cores for Das-Pronto objects (I will come back to this again later) and sculptures. So buy some, those materials are cheap.
For the polymer to stick to the polystyrene you need to spread some two-component, quick-cure epoxy on the surface of the white chunks; this will also secure the volumes better to the metal wire.
Other hardening compounds may also work; however, some chemicals destroy polystyrene very quickly. If the one you happen to try does not, you will still have to wait much longer for it to harden than when using quick-cure epoxy.
Wait for the epoxy to harden before starting to sculpt.
Any such plastic clay piece must be heated in your kitchen oven to harden. A few needle-sized holes should be made in the bigger volumes of the polymer so that the gas fumes can escape from the polystyrene during heating. This way, you minimize the risk of cracks. You should also slow down the cooling process by wrapping hot pieces in some cloth, like a towel, until they have cooled down.
The Fimo wrapping pack instructions advocate a rather short heating period for hardening. I have found, however, that it is better to prolong this process. Fimo is supposed to be baked for 20 minutes at 120 C, a period that will allow for most sculpt sizes to come out hard; however, they will be brittle and vulnerable to the smallest little mishap. Instead, keep it in the oven for an hour, or even ninety minutes.
The colour of the piece will yellow and darken to some degree, but the final result will be much tougher and more durable. But avoid using too high temperatures, as this may destroy your work and cause poisonous fumes.
I once nearly caused a fire by forgetting to adjust the oven temperature, having cooked a meal immediately before curing a polymer piece.
There is also the issue of noxious fumes.
I have no expert knowledge about the actual chemistry involved in this, but the manufacturer does supply a warning about overheating and heating for too long. So I make sure to have proper ventilation when curing my sculpts, and my advice is to do the same.
One particularly great quality of polymer clay is that you can rework a piece several times by cutting away parts after hardening to put on new, soft material and then harden the whole piece again. Take note, however: since polymer will darken during heating, any further additions of polymer will turn out lighter in shade than the prior ones. So this reworking may force you to paint the piece's surface to make the sculpt uniform in colour.
Personally I find this to be a small price to pay for this extremely convenient flexibility.
After the piece has hardened you may want to paint it. It is important that you render the surface ready for this, as the cured polymer and your fingerprints on it will make a slightly greasy surface, which may repel paint to some degree.
Use a clean, old white rag or some tissue paper and scrub the polymer surface with industrial grade alcohol (isopropanol). Avoid white spirits or other members of that unfriendly, slow-drying family.
This washing will make any paint stick better to the surface of the piece.
In addition to the scrubbing, you can sand the piece lightly with fine sanding paper, but only if you think it will look good without the very finest details. Sanding should be done before washing with alcohol.
In many cases you actually need a smoother look to an object. You can cut, file, sand and polish to your heart’s content, as this modelling material is extremely versatile.
So sanding will make paint stick even better to the plastic and is advisable in case your project might suffer some wearing. If this is the case, also put some varnish on top of the acrylic paint. This can be matt or shiny; the spray variety, or whatever you prefer.
A further word about chemicals:
I use thin rubber gloves when handling enemy-category chemicals. Open windows before you begin to work; get plenty of fresh air in, avoid inhalation of fumes and stay well clear of electrical charges or open flames during the operation, since alcohols, both liquid and fumes, are quite flammable.
I addition, do not forget to protect your lungs when sanding. Wear a mask! This will make it possible for you to keep breathing much longer after you reach middle-or-old age. You will want that.
I never much liked working with plastics other than the "clay" variety, but I do turn to them in hours of dire need. Some of these compounds have changed since I first began losing countless brain cells, nose down in pots full of stinking, dangerous brew.
Today, you can find seemingly smell-and-risk-free plastics for a variety of purposes. Nonetheless, my scepticism about these products never completely evaporated. Who knows what they will discover years from now? Perhaps tumours are stealthily growing in the model-maker communities as we speak, globally, lethally, tragically.
I have therefore learned to take precautions with any chemical substance that does not naturally belong in my refrigerator or food storage. I do this in the hopes of expanding my life expectancy.
Do the same even if you are young; youth is a condition that will soon pass.
Always be wary of chemicals that make you dizzy, I say.
Larger works sometimes demand other solutions than polymer clay.
The reason for this is partly the rather steep pricing of plastic and perhaps more importantly, the fact that polymer clay is difficult to heat and cure successfully in large chunks.
Yes, very difficult and unpredictable, believe me, I've been there:
It's around midnight. I have in my hands a cracked, large polymer piece, still warm from the oven and it's only a few hours until planned delivery to my client.
Bad planning, bad material for the job.
And absolutely no fun.
I have since found Das Pronto and a couple of other such paper-based products (Silkis, Paper Clay) to be excellent for many larger projects. Das P., as much as others of its kind, is actually a commercial, air-hardening, light grey paper-mâché, but the "clay" name seems to have stuck in this case.
Notice, however, one disadvantage is that these other “clays” often force you to plan further ahead, since they take considerably longer to harden, making them unsuitable for on-the-run activities.
My other materials include all the common, everyday stuff, such as cardboard, foam-board (Capa-board), metal wire, wood, balsawood, latex, white glue, superglue (big dashes make your head swim, so beware!), building-silcone, and two-component- casting formula silicones, etc.
My working procedures have evolved interestingly since I first started working in this field. One rather dramatic factor was that I at long last became certain that I could do my own photography well. I have lit and shot almost all of my own work ever since.
Photoshop, however, is what really, really changed everything for the better.
For many years my work was completely fingermade; that is to say, without digital elements. However, since around 2003-2004, I have hardly done any project without some sort of computer-work.
Yes, that´s how slowly I was getting it.
"Duuhh!" you might utter.
"B-b-b-ut how was I to know!" I´d be likely to stutter.