Cap America Shield Mothermold

[Sisko4]

I am currently molding a near Movie accurate (95%) Cap Shield.

There is one Layer left for the start of the Mothermold.

Problem is, that i´ve never made such a big Mothermold.

I need it light and very stable, Mold has 3 Keys.

Should i go with regular expandable Spray-Foam, Fiberglass and/or Rondo?

[ventrue]

Just a thought, since I don't really know much about moulding: Why don't you use a layer or two of fibreglass and add vertical parts to it for added stability?

[Noskey]

I don't have any input for the moulding, but I'd like to see the progress down the road.

[torsoboy]

I truly do not intend to sound like a downer here, but you should probably just forget about it being light all together. In general, that's an unrealistic expectation for a mothermold. If it ends up being light in the end, hey that's great. But you're primary concern for a mothermold is that it should hold it's shape and the mold's shape and be strong enough not to deform under whatever pressure you might put on it (while casting or while in storage). The larger the overall mold is, the heavier it's going to be. Fortunately since it's essentially a big circle, you should be able to get away with doing a few layers of fiberglass mat (not fiberglass cloth), and like Ventrue suggested above, add some additional supports in there for good measure. Jigsaw some MDF or plywood to fit the shape of the mothermold, and just fiberglass those suckers directly to the mothermold. That should be strong enough for you.