Green Stuff

Not to be confused with Soylent Green. Kneadatite, a.k.a. Green Stuff (often shortened to simply "GS") is an epoxy intended for plumbing repairs, but frequently used for miniature conversions and sculpting. It comes in two parts. One is soft, yellow or light-green, and sticky. The other is stiffer and blue. The user kneads the two components together to make a sticky green putty (hence, both of the names) which they can then make into the desired shape. It's available in several formats, including large tubes (where rolls of yellow and blue are sealed in separate packages) and rolls of extruded "tape" that have the yellow and blue side-by side. The tape is easier to measure quickly, but the contact area between the two components begins to slowly cure over time.

Professional sculptors have used Green Stuff for decades, to the point that the original master models for gaming miniatures are called "Greens" even if they're made with another material. It really took off when the Ral Partha casting team realized the springy, heat-resistant final models would work with their new vulcanization and spin-casting system, and it became the industry standard for mastering metal models until the turn of the Millenium. Several manufacturers now make special molds and rollers for quickly making parts like tentacles and base toppers at home, and many 3-D printing sites will have patterns for similar tools.

Of course, when it comes to Games Workshop, the Green Stuff they sell is incredibly expensive and packaged as poorly as possible - selling 4" strips of the tape in a blister pack for the same retail price as the original manufacturer charges for an entire three-foot roll - or at least it was, as they no longer sell it in any form. Other gaming companies also repackage Kneadatite, usually as "Green Stuff", at varying levels of price efficiency.

Sculpting Tips and Tricks

The WIP general links to many useful tutorials for the would-be sculptor, but here are some basics.

• Because uncured GS is very sticky, you should usually apply the stuff you intend to sculpt to the general area of the armature you want to work from, then let it cure for 15-45 minutes before working with it. Keep your tools lubed up with water, chapstick, or vaseline. Always clean the surface of the mini with soap and water or alcohol to pull any residual grease off, or else the GS will be sticking to you instead of the model.
• If you want to do hard, metallic parts like mecha or weapons, it's usually better to work with another putty. See below for more. You can, however, vary the mix up to about 2:1 of yellow and blue either way, and it will still cure (albeit more slowly). More blue makes the putty harder and dryer, more yellow is softer and stickier.
• Parchment (aka Baking) or waxed papers work well if you need to roll it out.
• For hair and other very fine lines, it's usually best to use a hobby knife and cut the lines in when it's nearly dry.
• Always work in thin layers, rather than trying to throw down a whole arm in one go. Also try to work on one area at a time, and support the mini on a cork or other handle. There's nothing worse than exquisitely sculpting the fingernails and knuckles onto a mini, turning it over in your hand, and feeling all your work sink into your own fingerprint a second later as you adjust your grip..
• Uncured GS becomes softer and stickier when heated, but it also begins to cure much faster. Conversely, freezing or chilling it slows down the process and makes it much easier to get hard, flat surfaces - though it will have difficulty sticking to the armature or miniature being converted. On a hot day, make sure your model is supported while curing. If you don't, it could "slump", losing detail and falling to pieces. If it is properly-supported, however, you can use an incandescent light bulb to speed up the curing process and get on the next layer faster.
• Super glue reacts very strongly with uncured GS - it will form a hard, pebbly skin almost instantaneously. Unfortunately the inside of the putty will still take just as long to cure, and bonding parts this way means they will usually wind up tearing apart later. It's better to pin the model first, though you can use flash-cured GS to help fill gaps on the inside of a joint on a metal model.
• Don't use your files on it until it's ALL the way cured. Otherwise you're going to have to clean rock-hard putty out of your ruined file. There is a tool, called a "file card", that's made to clean out a bodged-up file, but it's easier not to screw them up in the first place

Alternatives

Green Stuff is not your only option. The following is only a brief summary of some of the more-popular alternatives:

• Tamiya Putty: Also known as Tamiya Putty Basic Grey Type, this liquidy grey goo comes in a tube straight from the ancient Eastern model-mongers themselves. It's mostly used by the scale model and diorama communities, since its purpose is to fill and smooth out surface gaps and trenches in areas where two parts meet. This is generally more important for multi-part model airplane or model tank kits, but it can be very useful for high-detail customs built for tabletop wargaming. Protip 1: It shrinks a bit when it dries, so use some excess and sand it flat later. Protip 2: Mix this with plastic glue to make realistic weld seams and energy weapon impact craters on your tanks.
• Air-drying clays and cellulose clays: Don't. Just no. They're trash for working on minis (though cellulose clays can be useful for terrain).
• Sculpey and other polymer clays: These will not dry out until baked, and are either waterproof or water-resistant. While they don't hold fine detail very well, they make a very convincing concrete texture and are much cheaper than epoxies. Many sculptors use polymer clay to "bulk out" a mini, making the general shape out of a cheaper clay and only using the putties on the top surface.
• "Brown Stuff": A variant on Kneadatite made with aluminum powder and a slight formula tweak. Brown stuff is stiffer and less-sticky than green stuff, and it files down to a smoother surface.
• Apoxie Sculpt: Another two-parter, softer and less-sticky. White, holds a little less detail but extremely easy to smooth. Sands well. Very cheap in bulk, and often used in terrain projects as a result.
• Milliput: Yet another 2-part epoxy, usually yellow or terra-cotta. Cheap, somewhat fragile, and grainy. It cures very quickly and can be smoothed out to a near-mirror finish with water or isopropyl alcohol. Very popular for Blue Stuff casting, bulking out armatures, and bases. There's a "fine" white version, but it's not noticeably better than the others and costs half again as much. You can mix Milliput and GS for various interesting effects, and the GS will strengthen the otherwise crumbly Milliput.
• Beesputty: A hybrid epoxy clay. It has a surface finish more like Green or Brown Stuff. Handles almost like a wax under tools, which means it can hold extremely fine incised details. You can manipulate surface effects with alcohol or water. Like polymer clays, needs to be baked to cure.
• JB Weld: Plumbing epoxy that comes in several varieties. It's cheap-ish and cures quickly. It's also toxic, smells awful, and does nothing that the other epoxies don't. On the plus side, you can use it to make sure that your metal models will never ever come apart again (EVER!).
• Plaster: An ancient material used by the greybeards of the model train sets community. It's not very good for fine details, but it can be bought in bulk and made into all kinds of scenery. It can also be used as a cheap cavity-filler or counterweight in large custom models.

Liquid Green Stuff

With the advent of Finecast, Games Workshop realized that they were going to have lots of bad molds. Rather than fixing the molding issues, they decided to make even more money by selling tools so the schmucks who bought flawed models could fix them themselves. This includes Liquid Green Stuff, a chemically-unrelated green putty similar to Squadron Gap Filler that has been thinned so that it can be painted into gaps. It is also grainy, crumbly, and exceedingly annoying to work with. Tamiya makes a similarly-priced filler that works a Hell of a lot better, or you can thin out Milliput about 2:1 with denatured alcohol for a similar result.

Links

• The original GS manufacturer's website - the store section has been offline for a while, but most e-tailers will have "kneadatite" and other putties listed by brand name for bulk purchases.
• Milliput
• Beesputty
• Apoxie Sculpt

Model Making
Modeling:	Guide to Assembling Models - Green Stuff - Model Alternatives - Casting - Photo-Etched Brass
Painting:	Guide to Painting Models - Paint - THIN YOUR PAINTS - Duncan Rhodes - 'Eavy Metal
Scenery and Technical:	Forthcoming...
Related:	WIP