a little bit confusing, but helpful. :3

>_< D'oh.. At the time, I didnt know how to illustrate the different layers very well. I suppose I should just take a photo of the inside of the head to show what I did. LOL

Let me know if you need me to explain any part of it. xD

I do have a couple questions, if you're willing to answer...Where do you purchase your BBFoam? I can't seem to locate it anywhere, and I also wonder how you attach the bbfoam to the actual head-foam? Is it with glue? (I assume you're using the soft poly styrofoam for the head, like most heads.)
And how does it form so that you can't see into the suit, and see your actual mouth? And do you sew in the elastic or just glew it? Because I imagine that gluing it in might lead to the styrofoam tearing after alot of movement. :/ hmmm....sorry for so many questions!! XD

Where do you purchase your BBFoam? We actually borrowed a chunk from a friend. He said he got it straight from a local manufacturer that sells boogie-board foam in large sheets. I've asked him what the more "technical term" was for the foam, but he didn't know. It is light-weight, hard and rigid like your average styrofoam but its as resilient as plastic. It doesn't break easily. He happened to make the entire frame of his fursuit from this stuff, and we thought it would be secure enough to drill screws into it for stabilizing the plastic piece for the jaw.
Here's his fursuit, with photos of the foam: http://www.sharkyweb.com/Suit_Version_1/

how you attach the bbfoam to the actual head-foam? Hot-glue melts BBfoam. To glue the green polyfoam to the BBfoam, we use a two-part epoxy. Though, I've recently heard fursuit-makers raving about E-6000 glue, so we may try that in the future. You can hot-glue fur to the BBfoam, but be mindful that it melts slightly from the heat. The BBfoam acts as a platform that your jaw presses against to open and close the fursuit heads' mouth. We cover it with a Foamie sheet for comfort.

And how does it form so that you can't see into the suit, and see your actual mouth? My chin sits on a 1 1/2" platform of BBfoam and has a small brick of green polyfoam that is covered in black foamies which rests in front of my chin (below my lower lip), this is for controlling how well the fursuit jaw moves. Harp's entire mouth is lined in black foamies, so I camouflaged the platform and green polyfoam in the same black foamies. When I open the fursuit mouth and you look in it from the outside, if anything at all, you'll see the black brick in front of my chin, not my face. Theres only enough room for my mouth and nostrils to be seen at certain angles, the rest is in the mask behind the eyes. With my Harp fursuit, I must breath through the mouth, so I rarely close his mouth completely. If you look hard enough, you will see my upper lip if you stick your face into my fursuits mouth or use a very bright camera flash when my heads tilted up at a certain angle and the fursuits mouth is as wide as I can manage to open it.

And do you sew in the elastic or just glue it? We hot-glue one end of the elastic to the green foam (average cushion polyfoam) that the head is made of, then we hot-glue the opposite end of the elastic to the plastic piece that acts as a bridge from the head to the lower jaw. It's very sturdy. Our elastic is approx 3/8" wide and 2-3"long.

Don't worry.. I've got some photos lined up. I'll post them soon.

What do you recommend on how to make moveable jaws for more...solid heads? I'm thinking of sculpting one that would be cast into aluminum. Any tips?

I have no experience with casting heads in any material, I construct ONLY polyfoam-based heads (couch cushion foam). I've seen fursuit-makers use casted or heat-gunned plastic shells as their base for fursuits, and they usually have a separate shell for the bottom jaw that cradles your chin and pivots using a chicago screw (aka. "sex bolts" http://www.boltdepot.com/fastener-i.....pe-Chart.aspx) and keeps the jaw closed using a small strip of elastic. Of course, they don't post their construction methods online, but that's the jist. This method may work best for you. The shell looked similar to the orange and gray lines on my diagram.

You may want to post your question on http://fursuit.livejournal.com/ to get answers from fursuit-makers who cast their heads and build movable jaws for them. It would also help to give a concept drawing of your character, so they can have a good idea of what you will be building and what steps to take.

You are pioneering a different way of making fursuit heads, so you may have to perform a few experiments to get it to work the best for you. :3

Thanks. ^^ Also, I have ZERO EXPERIENCE making fursuits.

The reason why is that in my counterculture group's customs and iconography, the mask replaces the crown as a symbol of authority. And I'm looking for a 3/4-full head (does not cover the back of the head) cast aluminum fox mask to be one of the group's "relics".