Here's a Friday Quick Tip by request. Awesome friendly local game store BattleForge Games (plug: 20% off GW mail order) is running a Planetary Empires map campaign (which unfortunately I can't participate in). But BoLS Fly Lord BushidoRedPando has created an awesome portal gate for his Chaos army. I will promptly steal this idea for my Eldar, and in return, here's a quick tip for him on working with pink foam.
Now I don't gender sterotype with colors, so if your pink foam is blue, more power to you. I've noticed in my area that the insulation foam at Home Depot is pink and the same at Lowes is blue. The blue foam is stronger and the pink foam is more sensitive. I kid; either is fine and while I usually try to buy the thickest I can find, usually that is just 1/2" or 5/8".
There are a few key tools you'll need and most of them are pretty obvious.
Cut, shave, slice; using these depends on the size of the project. For a little piece of foam for a 40mm or 60mm base, all you are going to need is your hands to break pieces apart and a hobby knife. But when you go bigger you'll want a much bigger knife that cuts deeper. Always start with a fresh blade when working on a new foam project since a dull blade can pinch and pull the foam instead of slicing. The combo coarse-fine half round bastard file (yes, it is actually called a bastard) is great for smoothing curves or rounding pieces, especially when you have joined multiple layers of foam together.
While this foam cutter is a pain to work with because the blade sometimes slips out, I wouldn't work with any other. The closed, U-shaped cutters are only good for something small and this large, blade-style cutter really makes it easy to cut recesses and concave shapes that would be impossible with a hotwire-style cutter. (Plus, using this thing in some huge chunk of foam always reminds me of the lightsaber-into-blast-door scene from Star Wars: AotC. Geek-tastic, I am a foam Jedi.)
Oh, yeah: the scallop edged serrated bread knife. Steal this from the kitchen while no one is looking. If you are working on a large foam project and cutting through many layers, there is no better manual tool out there.
If you are working on something really big, don't be afraid to break out the jigsaw, belt sander or any of the other power tools. Foam is really easy to cut with any blade, but a finer tooth will give you a smoother edge. Sometimes you will want a rougher edge, so you really can't go wrong with just about anything you have in the workshop.
Pink foam is best used as a volume filler or texture. Here are a few small projects where I've used foam.
With the crate I've used the foam for texture, to provide a nice rocky appearance. I broke this piece off by hand and carved a channel for the crate to show it cutting through the mud, down to the hard rock as it landed. The snow drift in the bottom piece is pink foam used as a volume filler. I used a small piece of foam that was filed into a soft snow drift-like shape and then painted white, covered with glue and textured with snow flock.
Here are a few teaser pictures of a larger foam project I created for BoLSCon. For this project we wanted a piece of terrain that was tall enough so that a squad could be at the base and an unit with Infiltrate could be legally be placed in the terrain piece above it-- so all the required distance between the units would be vertical, not horizontal.
The piece is 12" x 12" x 1/2" foam layered together into one cubic foot of pink foam, bonded with Gorilla glue. Above I've just started roughing it out with the bread knife to get the basic shape.
Here I've made more rough in progress and you can see some of the horizontal foam cutter texture going onto the top portion and doorway carved out with a hobby knife. Below I printed an Imperial logo on the printer and cut it out with a hobby knife, using the big bread knife to shape the surroundings into the shape of the larger piece.
A few final tips: to seal exposed foam for spray priming or painting you have several options depending on what your final texture will be. If you are going for a rocky foam texture then I usually seal the foam with latex or hobby paint (or even good paint if the piece is for a small base). Optionally you can use watered down wood glue. This works especially well for a foam piece that you are going to texture with sand or another material. I've also use spackle for covering foam, if I'm going for an irregular rocky texture and just using the foam as a volume filler.
Joining several layers of foam together can be tricky, depending on the project. Wood glue is my normal go-to adhesive, although when dried and hard it is really tough to cut through. The good thing about wood glue is that it doesn't expand much and can create a good bond for a big stack of foam layers with minimal gap between each layer.
Gorilla glue also works well, if a little expensive, because it is easy to cut because of its foamy dried state. Just be wary of layer expansion and gaps if gluing multiple layers. Clamping or putting a big heavy weight on it will ensure that the excess goes out the sides and won't separate your foam layers.
If you are joining multiple custom shaped pieces of foam together, I recommend hot glue. It will create a quick strong bond that you can cut through with a hobby knife. Just don't use hot glue on a foam sandwitch: the stiff hot glue bead will tear up the foam when you cut it.
What's your best tip or tool for working with foam?