In this episode, I put some time into building up the armature. The armature is the foundation. It's more than the skeleton; this is a rigid base to the structure. Bits of wood here, bits of plastic there. How to do combine elements but make them rigid? So far, I used bolts, screws and strapping to hold the elements together. The goal of this round: get the lower armature ready to bulk up. Then, I would bulk the structure with three material: soft foam, mesh, rigid foam. Soft foam, you can work into the nooks and crannies to get the general shape right. The soft foam does two things. First, it bulk up the structure as you would desire. Second, it's an insulating layer between rigid stuff underneath and the eventual fibreglass surface. Imagine that stretched for the winning baseball and your bone popped through the skin (ew). This soft layer adds some forgiveness and shock absorbing between the fixed layers beneath and rigid layer on the top. On top of this thing layer of soft foam, I put a layer of thin mesh over top of that. The mesh has a wild role: it gets into the middle of the rigid foam and holds it in place until the rigid foam is sprayed in place.
Great Stuff is a spray can full of polyurethane based insulating foam sealant. Great Stuff foam has lots of imitators and largely, they are okay substitutes. I am using this to bulk up the armature. The problem: Great stuff is a hand grenade, not a laser. I need accuracy. Can you make this accurate? The quick answer: no. The foam goes on like bubbles (ever shape a bubble bath?) then it expands as it cures and sets up. You can aim it better for better effect, but you can't control it surgically.
After the foam is laid down and it cures (oddly enough-- water promotes curing), I am going to hit the foam with a sander (for coarse detail) and a dremel grinder (for fine/hard-to-reach details). The end results of LOTS of sanding will be a silohouette that is ideal. I say "silohouette" because there are dips and gaps. That's going to be okay because I will lay down taut sheet of fibreglass that will go over these gaps.
What I discovered: there are strong parallels between building this sculpture and making a surfboard. Thanks to the Internet, I was able to find this relatively extensive how-to for how-to make a surfboard.
