Friday, September 11, 2009



Today I want to talk a little bit about armatures for sculpting miniatures.

I guess most of you are familiar with the basic aspects of sculpting miniatures. So you surely know that you’ll need a solid foundation for putting your putty on if you want to sculpt a humanoid miniature (and not only a “blob”).

There are two alternatives for such a foundation.

1. You can take a so called dolly. That’s a skeleton-like substructure cast from white metal. There are several different versions of these dollies available from different manufacturers (for example: Reaper, Ebob, or Hasslefree Miniatures to name a few).The advantage of the dollies is that you don’t have to worry about proportions, because you can use them just like they are. The disadvantage is, that because of the material, they are made of, they break quite easily when you try to bend them to get the limps into the pose you want to have. Because of that, some (more extreme) poses can’t be sculpted with these dollies. Another disadvantage comes from the preset proportions, because only small variants are possible.

2. The second way to build a foundation for your sculpt is to make an wire armature from scratch. Usually two pieces of wire are twisted together so the twisted part forms the torso, while the wire ends are bent to form arms and legs (pic. 2).

The advantage of these wire armatures is that you can do every pose you like. The wire can be bended easily into the needed position without breaking. You also can do every variant of size and proportions because you do it all from scratch and so there’s no restriction to pre-cast proportions. In reverse, the disadvantage is that you have to find the right proportion again every time you do a new armature. Another disadvantage is that it is difficult to get a “5 point armature” (1 head, 2 arms, 2 legs) from twisting two pieces of wire together. Usually you can choose between a “3 point armature” (head and legs) or a “4 point armature” (two arms and two legs). In both case you have to add an armature/wire for the arms (3-point armature) or the head (4-point armature) later.

So both, dolly and armature have their advantages and disadvantages and I thought about a way to combine the advantages of both, while eliminating the disadvantages.

So I came to the idea to cast my own “dolly” with cast-in wire parts for the arms and legs.
The advantage of this hybrid-armature is that you got a “5 point armature” with some proportions, but also with legs and arms, that could be bent without breaking.

I developed two versions of this kind of armature (I call it “Schellert-armature” because of my last name). The first version has a complete torso including hips while the other ones torso exists only of head, neck and ribcage.

The first has more given proportions while the other one allows more adjustments regarding the height. On pic. 3 you can see the two versions and their use.

I admit that it’s a bit of work until you get such a hybrid armature because you have to do a “master”, build a drop-casting mould from it and then cast the armature. Maybe it’s too much work if you just sculpt a few miniatures. But once you’ve got the mould, you can cast as much armatures as you like quite fast. So if you need some more armatures for your work, maybe it’s worth to invest the time.

So this is how you can make your own “Schellert-armature”:
I assume that you are familiar with the process of making drop cast moulds from heat resistant rtv-silicone rubber, because I won’t describe that. If not, there are lots of tutorials that can be found on the internet. It’s really not as complicated as it might look on first view.

First of all you need an “original” of the armature. Instead of wasting many words about how this has to be made, I just show you in pic. 4 how my master-armatures look like.

To fix the wire parts, I just drill in small holes into the sculpted part and glued the wire in. I used wire with a diameter of 0.8 mm for that.

To make it clear:
For the original, I took 4 pieces of wire and glue each of them into a hole that I’ve drilled into the “torso”. For casting the armatures, I only use two pieces of wire. These two pieces are twice as long as one of the 4 wires used for the original. These longer wires are bent and will be placed into the mould before closing it. Then the molten metal will be cast into the mould and around the wire parts, so they will be fixed tight into the torso of the cast armature.

I made two different versions of the Schellert-armature that I called x-type and y-type.

The x-type has a full torso with head, chest Spine and hips. So while the size of the torso is fixed on this “dolly”, you can do a little variation with the length of the arms and legs (wire parts).

The y-type torso exists only of the head and chest without casted spine and hips.
Instead of the spine and hips there are only the wire parts. On this version you can also do variations to the length of the torso, because spine and hips have to be formed out of the wire, so you can choose the length of the spine. So with this kind of armature, you can do miniatures with different sizes (see pic. 3 above).

So the trick regarding the wire parts is that when the metal is cast around them, they are perfectly fixed.

On the x-type armature, the two arms are made from a single piece of wire as well as the two legs.

On the y-type armature left arm and left leg on the one side and right arm and right leg on the other are each made of a single piece of wire.

If you have problems sculpting the torso or if you are unsure about the proportions, just buy the Reaper-dolly (the “advanced” ones), cut off arms and legs and use the rest as a starting point for sculpting the torso. When the torso is done, just drill in holes and add the wire parts.

Then you have to make a drop cast mould with heat resistant rtv-silicone rubber from it. In relation to a full 30mm miniature, the part of the armature that has to be cast with white metal is quite small and this could be a problem for the casting process. So the white metal that you’ll cast into the mould should have enough “pressure” to fill the whole cavity of the mould. To achieve this I recommend an extra-large gate (sprue) as you can see on pic. 5). If this gate is filled with molten metal, the weight of that metal will give the needed pressure.

While making the mould I also recommend the following:
You have to set the parting line on the object you want to make a mould from to define, what’s in mould half A and what’s in mould half B. Usually you try to set this parting line roughly into the middle of the object to get a well balanced mould.

But in this case you shouldn’t do this. Because later you have to put the wire parts into the mould it would be easier if the cavity that holds the wire is a little deeper. This helps to prevent the wire parts from accidentally falling out of the right place while casting the molten metal in. So try to create your mould in a way, where the wire parts are set predominantly into one mould half (see pic. 5b).

When you’ve got your mould with cut in gate, sprues and air vents you can try your first cast. Before you cast the white metal into your mould, you have to place two bent pieces of wire inside the mould as you can see on pic. 6a and 6b).

First you have to straighten the two pieces of wire. Then you have to bend them at the right point into the needed angle with a flat nose plier. You have to try a little bit to get the right angle. Place the wire parts into one half of the mould at the right position. Then carefully close the mould without letting the wire parts slip out of their positions.

Now fix the closed mould with rubber rings or a clamp or something like that and cast the molten white metal in.

The alloy I use contains lead. Personally I prefer this because the casted armature could be bent better when it contains lead and also the mould cavity is filled better because of the lead. If you don’t want an alloy with lead because of health issues, try a lead free alloy. Personally I’ve got no experience with lead free alloys for casting this kind of armature.

When the metal has cooled down and you open your mould, the white metal should have enclosed the wire parts. Remove the gate and the sprues and your armature is done (pic. 7).

If your armature didn’t come out right from the mould, it’s maybe because the mould is too cold in the beginning, so just try again. After some casts, the mould should get its working temperature. If the results are still not good, try to widen the cut, where the gate “touches” the cavity and/or cut some additional air vents.

That’s all. Now you got your mould and you can cast as many armatures as you like.
If you got plenty of them, you can use them also to do a pose study, just by trying out some poses to see how they will look. Because you already have the basic shape of a human (head, torso arms and legs) it’s easier to get an idea about how a miniature with this pose will look like.

1 comment:

  1. I just started a Ceramics class in college and had to find ideas for a project. I got bored and Bing-ed my name to see what popped up, and tada- I found this. Odd.. but cool.