Saturday, February 11, 2017

Some thoughts about the armature and the adhesion of putty

Ensuring the adhesion of crude putty on an armature is one of the recurrent potential pitfalls, early in the process of sculpting a miniature.

A method that was commonly used by Rackham sculptors, is to use Green Stuff (GS) as a "glue" between the armature and the Fimo putty they were using: a thin layer of crude GS (which is very sticky) is layed on the armature and a first layer of crude Fimo is layed upon it while still crude. Considering the low adhesion power of Fimo and the finesse of the Rackham minis, this is an interesting option.

I've used this technique for a while, but came across many trouble: air bubles, large cracks, not always very handy, sometimes cumbersome on larger minis, works less well with older GS, ... I never really knew why I had so much trouble (large cracks...), but since I stopped using GS, it's much better.

Another good reason of avoiding GS is when you bake your minis in your domestic oven: there is no info about how toxic it can be. For the same reason, I try not to use any type of glue on a mini that still has to go into the oven (cyano glues contain cyanide for example...).

Hence, I've developed a few tricks to make the adhesion easier. They are valid both for small and large minis, with both thick or slender parts:

Example of the use of 2 twisted wires to constitute most of the armature. I also use this technique to create small structures with the right shape to create some specific volumes later, like the hands (with loops), the head (with a loop or a "ball"), the ribcage, etc... .
Example of a thin wire twisted around the main armature, made out of a thicker wire. The picture also shows the loop for the head armature, and the "ball" for the chest.

- as much as possible, I twist the wires of the armature, which makes it much easier for the adhesion of any kind of putty. Either I use 2 (or more) wires twisted around each other as my armature, or I start from a single wire (with the right thickness) and I twist a very thin wire around it to create areas for a stable grip. This trick helps a lot.

Example of cores on a rather small and slender mini. In this case, I wanted to keep the arms very thin, so I didn't put any preparatory layer on them. Instead, I use the cores of the hands and on the chest as stable anchor points to start putting putty on the arms.
Example of cores on a larger miniature with bigger volumes. Here, I wanted to be able to adjust the pose of the mini up to some point, so I've left all the articulations free.

Example on Helltoy V2. (1) Creation of a simple armature for the body, with wires twisted at the level of the chest, and a loop for the head. (2) Addition of the cores: one for the head, one for the chest and thin layers on the bottom of the leg. Laying putty on this kind of wire is not easy, so I do it only where it has a bigger impact, and where it is easier (like straight parts). (3) The mini is created step by step. The putty around the hips is stabilized indirectly by the cores of the chest and of the lower parts of the legs.

Other example, this time a more chubby mini (B.O.S. of PC XII).

- I create cores as a complement to the armature (as explained in my other tutorials and WIPs; see here for example). They are very helpful for the adhesion of crude putty because of the larger and flatter surfaces they provide, and even much more if you scratch the surface of the cores (which I advise strongly!). They also provide a strong base for laying crude putty, hence an overall stability of the volumes during the sculpting process.

Illustration of how putty can be laid down in a progressive and stable fashion. More comments in the tutorial about sculpting a Skull Vato.

- in all cases, it is recommended to lay small bunches of putty, with the right shape. This is fundamental. A small quantity at a time, that you settle properly, making sure the adhesion is good, before you take care of the next bunch of putty. Otherwise, you'll face a good old domino effect sooner or later. Trying to set a big volume at once, especially directly on the armature, is an almost automatic failure. It is also better if you adapt the shape of the putty to ease the laying down of the neighbour bunch of putty, by creating a slight slope.

- The putty also makes a difference: a polymer putty that's a bit old will be less sticky in general. Sculpey Firm is much less sticky than Super Sculpey. Fimo is somewhere in between, depending on the type. Hence if you really want to work with Sculpey Firm, for example, you can start by using a mix of Sculpey Firm and Super Sculpey like you would have used GS, to ease the adhesion to the armature and to the cores, by providing a slightly sticky surface for the layers that will come on top of it. If I want to create cores, I will favor a softer putty like Super Sculpey used alone; if I want to create a base layer (crude), I will use a mix with a bit more of stiffness to it, to improve stability.
In all cases, according to me, it is very useful to use a different putty or mix of putty according to what you need to do.

- When discussing that topic on a forum, somebody also pointed out the possibility to scratch the armature with a file to improve the adhesion. If you try this, make sure to avoid the folds, where the wire is bent, as this might become a weak point, prone to break.

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