Opera Singer Diva From Fifth Element Molding and Casting Questions
Hi everyone! This is my first cowl so I'm kinda nervous on how to mold and cast this thing. I plan to mold it out of plaster with the wall running vertically down the tail for a two part mold. I'm trying to cast using flex foam three from smooth on but I'm concerned as to how I will get the natural head shape molded into this flex foam cowl without it exploding. Any and all help would be greatly appreciated. If you think it'd be easier to break it down into pieces let me know.
Your plan to use a 2 part mold running down the center sounds good.
To get a nice blending edge with the head, you'll want to use a head core as the 3rd piece to your mold. The head core is just a casting of your head form that can lock into the other 2 mold pieces.
You'll also want some bleaders or a spout for the excess foam to expand out of, so your mold does not pop at the seams. As the foam expands out of the bleaders/spout just wipe it away. Depending on how much the foam expands you may want to add more places for it to expand to prevent too much pressure from building up. I would try and hide them on the underside of the back of the head, and possibly the end of the "tail" on the bottom. The one in the "tail" could also help prevent an air pocket from forming. Where you place bleaders/pour spouts/injection points also depends on how you want the mold to sit as you fill it.
There are 2 main options for filling the mold: Pour it into the mold, then close everything up tight with mold straps. Or strap the mold closed to start with and then use an injection point to inject the foam until the mold contains enough to fill the mold as it expands.
Just make sure to rotate the mold a bit as your fill it up to prevent air from getting trapped in the curly tip of the tail if you don't have any bleeders there.
You can also brush in a layer of liquid latex inside your mold before closing it up if you want a latex skin on the cowl.
This webcourse with Bruce Spaulding Fuller covers making a 2 part cowl mold with a head core:
He does not run foam in the head for that webcourse, but it's a great overview of breaking down your sculpture and molding with cores.
That entire lesson series is worth watching if you are interested in doing character makeups. I learned a lot from it.
Best of luck!
Silicone can work too, but the problem there is that the pressure from the expanding foam can deform silicone.
Here's one video showing polyfoam in a closed silicone mold that appears to be backed with stone:
You can see that they provide holes in the mold for the expanding foam to escape from.
Even better (and likely exactly what you need) is this video showing someone running polyfoam in a 2 part stone mold with a core. It's a 3+ hour long video, but you can skip around as needed: