Tips for Making Accessories
MATERIALS:
Choosing the right materials to use is of extreme importance. If you need something to be very light, I'd suggest papier-maché, foam or plastic. If it needs to be very strong, go with plastic, fiberglass or metal. If it needs to be flexible, try upholstery or craft foam. Scout around your house and neighborhood for things to use as molds or bases on which to build your accessories; plastic bottles and containers can make great bases for shoulderpads. I even saw a breastplate recently that had been made from the torso of a plastic mannequin!
FIMO/SCULPEY: A popular choice for accessories and jewellery; they're quick and easy, and come in dozens of colours. They're great, but large pieces can be a bit heavy. Bakes in the oven at 350°F.
Foamcore: A craft board consisting of a layer of stiff foam sandwiched between layers of card. Available at any art supply store, it's great as a base on which to build papier-maché. Foamcore isn't particularly strong, though, so large pieces made of only one layer of foamcore can bend. It's best to reinforce large pieces with more than one layer, or go for Gatorboard, which is a much thicker and stronger (and also somewhat heavier) version of foamcore. Foamcore can be cut with a utility knife, whereas Gatorboard requires a saw. Both can be carved to some degree once you remove the paper surface. For an example of a piece made out of foamcore (covered in papier-maché), see my Neoranga shield.
Papier-maché: Very lightweight and inexpensive. There are two methods: pulp and strip. Most people are familiar with the strip method--simply rip up newsprint into strips (the smaller the piece you're making, the smaller the strips), dip into a mixture of water and wallpaper paste, and apply in layers. One trick is to build the shape you want out of plasticene, then cover it in papier-maché. Once the papier-maché is dry, just pull it off the mold.
Bags of instant pulp are available at many art supply or hobby stores. Once dry, pulp maché can be sanded, carved and painted. You can make your own pulp, but it's time-consuming and messy. If you really want to try it, go here.
Paperclay: A lightweight alternative to Fimo or Sculpey, available at many hobby and art supply stores. It's like papier-maché but comes in a claylike format. Just shape, let dry, sand and paint. It's possible to get an extremely smooth finish with Paperclay. Be advised that Paperclay shrinks slightly as it dries, so unless the piece has room to shrink some cracks will appear. These can be covered up with more Paperclay. Paperclay can also be carved quite nicely.
Plasterstrip: Strips of open-weave fabric covered in plaster; water-activated. Available from some art supply and/or medical supply stores. Sets fairly fast, but takes at least a day to dry completely. Great for making body casts, but make sure to cut it off the person before it gets too hard for scissors. Very strong, but can get heavy if many layers are used. Keep in mind that it doesn't give you a smooth surface and you can't sand it (it's based on loose-weave fabric), but you can cover it with a layer of polyfilla or some other spackling compound and sand *that* nice and smooth. Works quite well.
When working with plaster, it can be a pain when it hardens in the bowl or bucket and you have to chip it out (or just throw out the bucket). A good method to get around this is to use rubber bowls for mixing the plaster. Because the bowls are soft and pliable, when the plaster hardens you just squeeze the bowl a bit and the plaster falls right out. You can probably get rubber bowls at jewellery supply places, or any place that carries mold-making supplies.
Plastic: Here's my tutorial on dealing with thermoplastics.
There's also a new product called Wonderflex, which is like thermoplastics but becomes pliable at a lower temperature so you can work it with your hands (and without toxic fumes!). It's available at Dani's Cosplay Supplies.
Friendly Plastic is another heat-formable plastic product, which becomes malleable in hot water and can be shaped by hand. It's good for coating Wonderflex and for sculpting small items. It's available at Dani's Cosplay Supplies.
Styrofoam Styrofoam can be a quick and easy base on which to build pieces, but it requires a bit of preparation before painting it. Spraypaint will dissolve styrofoam, as will brush-on enamel paints, so you'll need to completely cover the styrofoam in gesso, acrylic or latex house paint before spraypainting it--this will probably take a few layers. Even the smallest gap in coverage can lead to a big mess as the styrofoam dissolves under the paint, so be extra careful.
Upholstery/Craft Foam If your piece needs to be both light and flexible, foam is a good choice. Upholstery foam can be found in some fabric stores, cannibalized from an old couch, or obtained from an upholstery repair shop. It comes in thick blocks and can be carved and shaped to whatever you need, then covered with fabric. It's a popular choice for armor, especially kneepads. Craft foam is available at craft stores and comes in thin sheets in various colours. It can be cut out into various shapes and then glued or sewn on. I've also seen craft foam used as face decorations, and it's great for armor when coated with sheet plastic or reinforced with glue.
TECHNIQUES:
Sanding: To quickly get rid of large lumps, use a coarse grit sandpaper (50). To get a porcelain finish, start with a medium grit sandpaper (80 or 100) and finish with a very fine grit (300 or 400). It's best to work in stages, progressively using finer and finer grits.
Painting: When painting uneven surfaces, apply a few coats of gesso (this is available at art supply stores) and sand with very fine grit until smooth; depending on how uneven your surface is it may take many layers to get smooth. I use acrylics almost exclusively; they're quick-drying, easy to use, waterproof once dry, and clean up with soap and water. Make sure to wash your brushes well.
Glueing: There are many glues available, and choosing the right one for your needs is very important. 5-minute epoxy comes in two tubes and you mix it together to make it work. It's very strong, versatile and works well for most glueing needs, but isn't flexible when dry. Superglue is good but again not flexible when dry. For flexible things like leather and attaching boot covers, shoemaker's glue (aka Barge), available at shoe repair places, is extremely strong, but use it in a well-ventilated area as it gives off hazardous fumes. 2-part epoxy putty is good for attaching things that don't fit perfectly, as it fills in the gaps, and can be filed and painted. For glueing plastic, there are special glues available at hobby stores that heat and fuse the plastic together. And of course there's old faithful hot-glue--it's invaluable for last-minute repairs, but normal hot-glue is very low on the durability scale as it can melt in summer heat and often falls off completely. Does not work well on smooth surfaces like metal. Hot-glue is great on foam and other porous materials, but make sure to get a high-temperature glue gun and hi-temp glue. The hi-temp glue is much more durable, but watch out as it is VERY hot and can burn you quite badly.
Finishing Tricks: There are a few ways to make your piece look more professional. The fact is, most crafting materials, even made into the right shape, will still just look like crafting materials. A necklace made out of gold FIMO will look like a FIMO necklace, not a gold necklace. There are ways to get around this, to a degree.
A very important step, especially with metallic surfaces, is breakdown. This term refers to distressing or emphasizing the surface details of a piece. The easiest way to do this is to apply a thin wash of dark brown, black or blue paint. It will run into the recessed areas, creating artificial shadows. This gives the piece dimension and realism. For more methods of breakdown, read this excellent article at Proptology.com. They also have information about creating convincing metallic surfaces.
For more control, you can manually paint in the shadows and highlights. In this way you can completely customize the look of the piece and make a flat, boring piece of clay or plaster look shiny and 3-dimensional. Even something that's the right colour, like FIMO, can benefit from some artificial shadows and highlights.
Once you're all done painting, give the finished piece a couple coats of clear spray lacquer (available at hardware stores, in the paint section). Glossy lacquer is the most durable, but if your piece should be matte then apply a layer of gloss (for protection) and then a layer of matte lacquer on top. Make sure to let each layer dry completely.