The scene in Spider Man 3 called for the heroine, Mary Jane, to again be in peril at the bottom of a giant spider web 40 stories in the air with cinder blocks from a nearby crumbling building falling dangerously close to her. Of course, real cinder blocks were out of the question in shooting the scene, so an effects answer was sought for just this scene. Gothic Prop Fabricators had made dozens of these blocks out of Smooth-On's FlexFoam-iT!® X 10 lb. flexible foam before for movies and commercials, too many to mention.
The below sequence shows how Gothic Props molded and cast these incredibly realistic blocks using Smooth-On's Mold Max® 30 silicone mold rubber and FlexFoam-iT!® X 10 lb. flexible foam.
The Mold Max 30 mold is placed in its wood mold box.
Wood supports are embedded in the mold rubber to help the mold maintain it's shape.
The lid has holes which will allow the pressure of the expanding foam to escape.
Sonite Wax is applied to the lid to keep the expanding foam from sticking.
The holes in the lid are coated with Sonite Wax as well.
The lid is firmly affixed using ratcheting mold straps.
Vinyl gloves are worn for safety.
The part A of the Flex Foam-iT! X is pre-mixed.
The part A of the Flex Foam-iT! X is measured out.
The part B of the Flex Foam-iT! X is pre-mixed.
An equal amount of Part B is measured out.
Black So-Strong pigment is added to the part B of the foam.
Green So-Strong pigment is added to the part B of the foam.
Finally, white So-Strong pigment is added to the part B of the foam.
The pigments are mixed into the part B of the foam.
The Flex Foam-iT! X part B is dispensed into the mixing bucket.
The Flex Foam-iT! X part A is dispensed into the mixing bucket.
The 2 components are thoroughly and quickly mixed.
The foam mixture is poured into a hole in the lid.
More of the foam mixture is poured into the other hole in the lid.
The foam is allowed to rise and cure for 1 hour.
After curing, extra foam material is cut away.
The ratcheting mold straps are removed.
Small pour vent sprues are cut away from the casting.
The piece is ready to demold.
The mold is inverted and removed from the wood mold box.
The wood supports are pushed out using a wooden rod.
The mold is ready to be opened fully.
The sides of the mold are peeled away.
The flexible casting is pulled away from the rubber mold.
A perfect casting, needing only a small amount of cleanup.
The flashing is cut away from the foam casting using a sharp knife.
The bottom flashing is also cut away.
Talcum powder is applied to give the piece a 'white/chalky' look.
The piece is ready to be used.
These lightweight castings are easy to move and safe to handle.
The flexibility and strength of the foam makes these castings very durable.
The process is repeated as many times as needed...for a wall of lightweight prop blocks.