WHAT IS GREEN STUFF?
Kneadatite or 'Green Stuff' is a putty that comes in two parts, one blue and one yellow, usually in the form of either a ribbon or a tube. Mixing equal parts of the yellow 'filler' and blue 'hardener' produces a sticky green putty that feels a lot like chewed bubble gum and it is from this resulting mix that Kneadatite gets its nickname 'Green Stuff'.
Once mixed the putty starts to cure until eventually it becomes too hard to shape. The working life of Green Stuff varies depending on how you store it, mix it, and work it, but the manufacturer PSI suggest a mixed 'work life' of between 1 1/2 to 2 hrs, with a cure time of around 4 to 5 hours reaching 'ultimate hardness' from 20 to 24 hours after mixing. It is for this reason that sculptors tend not to mix too much putty in one go. It is very easy to get caught up in shaping and working one area long enough for the rest of the putty you mixed to become unworkable and wasted. Green Stuff is not cheap either, so the less waste the better.
HOW DO I USE IT?
Green Stuff can at first be very difficult to work with, unlike Milliput, which shares many of the same uses, Green Stuff is incredibly sticky both before it is mixed and after. In fact it only stops being sticky when hard. It is this stickiness that often prevents gamers, collectors and modellers from doing little more with it than filling joints, or adding minor detail to their miniatures.
I will be covering tips on using Green Stuff in greater detail elsewhere on this site, but for now the basics are as follows.
To prevent Green Stuff from sticking it is necessary to use a little lubricant. Suggestions and recommendations vary depending on who you listen to, and I guess at the end of the day it all comes down to personal choice. I have encountered many suggestions ranging from Vaseline, Petroleum Jelly or Baby Oil, through KY Jelly to water, saliva, ear wax and I even read somewhere that grease from a sweaty forehead was good!
If you choose to use a petroleum based lubricant like Vaseline or Baby Oil, you will need to wash each piece of Green Stuff after it has cured, before you can get more putty to stick to it. Personally I use water, having a small pot at my sculpting desk. The sort of effects you can create with Green Stuff, and the detail you can impress upon it, depend largely on the type of tools you use (see below), and the proportions of yellow filler and blue hardener that are mixed together, since these can be varied.
ALL IN THE MIX
Before I start mixing up my Green Stuff I always make sure my fingers are a little damp; otherwise I find the putty sticks to my hands more than it mixes together. A little water on the fingers will release them and leave them free to work the Green Stuff into a well-mixed ball. Do not use too much water though, otherwise the Green Stuff won’t mix, it will just form into a stringy mess of folds and swirls, until the water evaporates and Kneadatite's sticky qualities return.
When your Green Stuff is evenly mixed, with no blue, yellow, or varied green streaks in it, and is just beginning to stick to your fingers once more, it is ready to work with.
Varying the amount of yellow and blue parts when mixing up your Green Stuff will give you both a change in the texture of the putty and a change in its characteristics when cured. Generally speaking a fifty-fifty mix is good enough for most conversion work or gap filling, but when sculpting a miniature from scratch, the ability to alter the putty’s qualities is both advantageous and desirable.
By mixing a greater amount of blue hardener with a smaller amount of yellow filler, you will achieve a putty that is very dark green in colour. This dark green putty is a little less sticky, usually cures in a shorter time and when hard is stronger and less flexible than a putty mixed with more of the yellow filler. I have mixed dark putties using as much as three parts blue to one part yellow, when I’ve needed a stronger and firmer result. It is important to remember that dark green putty will have a shorter work life than a more yellow putty!
Equally if you reverse the amounts mixed, mixing more yellow to less blue, you will create a putty that is lighter green in colour, much stickier in texture, remains workable for longer periods and is flexible when fully cured. Putty with more yellow filler than blue hardener is very good for working into detail, such as chain mail, fur, or hair. I use mixes of up to four parts yellow and one part blue depending on how freely I want the putty to move when pulling it around with tools. I find this mix very good for Dwarf beards or a horse’s mane. Such a mix does take longer to cure however!
Again the exact mix that is preferable to work with will come down to your personal preference and how much practice you have had. Most sculptors recommend a mixture of two parts yellow to one part blue, and I find this a very good mix to work with for the majority of my sculpting.
Milliput is good where a harder finish is needed.
Milliput comes in a variety of colours (Standard - yellow/grey; Terracotta and Superfine - white) and works along similar principles to those of Green Stuff. Where it differs however, the differences are significant and worthy of note. Firstly let’s deal with the similarities.
Like Green Stuff, Milliput is a two part (epoxy) putty consisting of a filler and a hardener, which when combined produces a putty with a similar work life of about an hour or two. The work life, curing time and final hardness of Milliput can all be altered by changing the ratio of hardener to filler in your mixture. There are other ways Milliput and Green Stuff can be manipulated and these are dealt with in the section on working it.
Milliput differs from Green Stuff in the following ways. Firstly and most notably it is cheaper than Green Stuff (Blue/Yellow Kneadatite), although in recent years a number of dealers within the UK have put their prices up, so shop around! Because Milliput is cheaper, it is a better choice for larger sculpts. Use it to flesh out your larger figures before applying a ‘skin’ of Green Stuff over the top of the fully cured Milliput.
Secondly Milliput has a much more ‘slippy’ and less elastic texture than Green Stuff and in many ways it handles like clay. I find this very useful when modelling wargaming terrain, or shaping the torso of a large monster or beast. Milliput can also be thinned and lubricated with water, however unlike Green Stuff you will find that adding water ‘dissolves’ the surface of your sculpt, again very much as you would find with clay. Thirdly, when cured Milliput can set very hard indeed, is not at all flexible (it will snap if sculpted thinly enough and without any internal wire support – see below) and is very good for carving and sanding once cured, if crisp hard edges are required.
There are other putties on the market, but I have not had reason or opportunity to use them as yet. A write-up on each will follow if and when I do have the chance to work with them.
Various grades of wire and cutting tools
A small soldering iron and solder
Loads of sculpting tools and interesting objects for mark-making
Some good reference material.