The Prop Builders Molding and Casting Handbook
8 1/2 x 11 Softcover, 225 pages
Price $19.95 Buy Me
A very interesting book intended for the theatrical props industry. The emphasis is on making parts fast without spending much money by using common materials whenever possible. Over 400 photographs showing over two dozen molding and casting materials in actual use. This is a very visual book and its just fun to browse through it.
You will learn new uses for common materials such as auto body filler, hot melt glue and silicone caulk, plus materials you probably never heard of such as Alginate, Water extended polyester, Celastic, Moulage and Picco Resin. Learn how to make soft rubbery objects, hard plastic parts, or even break-away window panes and glass bottles. Each material is shown being used to make a sample part, with photographs and a clear explanation.
This book doesn't give you as much technical information about each material as our # 002 "Molding and Casting" 4 book set. It doesn't tell you where to buy the product or too much about its compatibility with other materials, just what you need to know to mix it up and cast a typical part. I highly recommend that you also consider book set #002 as a companion to this book.
Vacuum Forming Info. The last 45 pages show you how to build a rudimentary vacuum forming machine. I don't recommend that you build this low performance machine, but you can get some good ideas from it. (See our #1001 and #1002 plans sets for more powerful vacuum forming equipment) The last chapter shows the vacuum forming machine in use to produce a variety of theatrical props, and shows how useful these machines can be.
The Model
You can't make a mold until you have a model or a pattern to work from. You can sculpt something out of clay or use an existing object. Sometimes its best to start with an existing object and then make changes by adding clay or other materials and sculpting new features
The Mold
The
mold forms a cavity that you fill with something else to make a part. Learn
how to work with rigid and flexible molds, from simple one piece open back
molds to split or multi part molds to handle undercuts. Work with the following
Mold materials:Plaster - Rigid, inexpensive and fast. Many
grades of plaster are available, but common "Plaster of Paris" works
fine.
Alginate-
Mix powder with water and it sets up fast to form a soft rubbery material that's safe for skin contact. This picks up fine detail and is the only material for making molds from hands feet etc... This is what your dentist uses when he makes an impression of your teeth. It has a short life and must be used quickly.
Latex Rubber-
Thin liquid rubber that is brushed on in layers to build up a skin mold. This material is very stretchy and can be removed from undercuts and other features, but it also picks up fine detail. Latex is often used with a plaster back-up for larger parts.
Silicone Rubber-
More expensive, but it produces a long lasting tough rubber mold that can be poured in thicker sections to create a "Block" mold of an item. Silicone can also be used with a plaster back-up to save on cost.
Moulage-
This is similar to Alginate, but is a lumpy gelatin compound that must be heated to reach pouring consistency.
Mold Releases
Some mold materials are self releasing, but others aren't. If you want to be able to remove your finished casting, then you must use the proper mold release such as Petroleum jelly, Wax, PVA, Green soap, Talc, and sometimes even water.
Making The Castings
More well documented examples of unique casting materials. Learn how to do Absorption Casting with liquid clay in a plaster mold. The plaster absorbs water from the clay, and when you pour out the excess you have a uniform shell. You can also use Neoprene rubber for absorption casting. See how to make a reinforced Latex mold from an uncooked turkey. Learn how to make Laminated Castings with a female mold using Papier Mache, Fiberglass and Celastic which is a plastic filled plastic that's activated by soaking it in acetone.
Work with "Hot Melts and Thermoplastics". Hot Melts, are moldable when heated and solid at room temperature. Some examples are Hot melt glue sticks, Waxes, Plasticine, and hot melt PVC plastic. Again, you get to see an item cast from each material.
Learn how to make "Break Away" glass for window panes and bottles. This book even includes a simple recipe for Sugar Glass that can be mad in your kitchen. A more modern material called "Picco Resin" is more popular than sugar glassand you get detailed instructions on how to cast a window pane and make a fake glass bottle.
Thermoset Casting Materials
Thermoset" means that a chemical reaction or cure takes place and changes the material permanently. A common thermoset is "Polyester" or Fiberglass resin. There are different formulations for laminating with glass cloth or for casting clear objects. A variation is "WEP" or water extendable polyester, where water is mixed in to the resin. This increases the volume and makes it like a very strong plaster part. Other materials are, two part Urethane rubbers and foams, Epoxy resins, and Silicone rubbers. See photo's of each material in use.
Some of these products may be new to you, but don't forget the common ones like Plaster, Silicone Caulking, Auto Body Filler and Hot melt glue.
Vacuum Forming with Thermoplastics
This
section shows how one clever props department put together a rudimentary
vacuum forming machine, and judging from the pictures, they put it to very
good use. The machine design shown is typical of a good
"first effort" and they even admitted it could use improvements
in some areas. I wouldn't be in a hurry to duplicate this design, but even
with it's limitations, its very clear that a thermoforming machine is a very
useful device.
Check out our construction plans #1001 and #1002 for more powerful thermoforming equipment if you really plan to build something. You can however, get some good ideas from their example, and see some of the amazing theatrical props they made. Surely they must have thought vacuum forming was a "gand Architectural moldings. Smaller examples are Antique clocks, fake books, giant banana leaves for a jungle set, fake fruit and figurines. Vacuum forming is a fast way to make lightweight and inexpensive duplicates very quickly.
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