When we think of fiberglass, we think of the smelly, toxic resins used to reinforce it. Many props people avoid fiberglass for that reason. Water-based resins offer a less toxic alternative. Aqua Resin is one brand which is useful for theatrical prop building with fiberglass. You need a dust mask when handling the powder, but once mixed, it is non-toxic.
Using fiberglass is one of the techniques that now has a step-by-step photo tutorial in the second edition of The Prop Building Guidebook: For Film, Theater, and TV, which comes out February 10, 2017. You can see all the companion videos at the Prop Building Guidebook website.
When I was a kid, I played a video game called Faery Tale Adventure that was filled with all sorts of magical items. I started making replica props of these items; I needed projects to show off various techniques for the second edition of The Prop Building Guidebook, and I wanted some props I could trot around to Maker Faires. The first one I have finished is a magic seashell, used in the game to summon a friendly turtle.
Seashell Model
The model was cut out of MDF and layered with pieces of cardstock. I used some Apoxie Sculpt to further refine the shape. I coated it to give it a bit of texture, then spray painted it gloss pink to seal it all together and make it shiny.
Clay covered model
Next I made a matrix mold of the shell. I’ll describe it briefly here, but I have a lot more information in my upcoming book. I also shot a video which I promise will be up later this summer. Basically, you cover the model in a half-inch of clay, build a box around it, and fill it with plaster.
After the plaster is poured
When the plaster is set, you remove the clay and put the plaster mother mold back. This leaves you with a half-inch air gap between the plaster and the model; fill this with silicon rubber.
After the rubber is poured
The silicone rubber mold ends up supported by the plaster, and I used the smallest amount of silicone rubber possible. Matrix molding takes a lot more prep work, but it leaves you with very clean-looking results, and saves you money on materials.
Laying in fiberglass cloth
To make the finished piece, I used fiberglass with Aqua Resin. Again, this was for the book; I will have a video of the entire process later this summer. I had never actually fiberglassed a piece from a mold before, so I learned a lot; the final seashell  was actually the fourth one I attempted, and the first I completed without anything going wrong.
Coating with Aqua Resin
Using Aqua Resin with fiberglass is similar to using polyester resin, but a whole lot less toxic. The end result is a bit more like plaster rather than plastic, but it is still fairly strong and lightweight. I have a few more alternatives to polyester resin that I’ve been wanting to try so I can compare the results.
Finished piece before paint
This was not really that great of a piece to demonstrate the advantages of using fiberglass. It is very flat; you can easily create it using sheet goods, such as lauan, and still have it remain strong but lightweight. Fiberglass becomes more useful when you need an undulating skin, like a mask, that needs to be hollow but retain a consistent thickness throughout. But these are things I think about long after I have begun a project, when it is too late to start a new one from scratch. I say this for those of you who will look at this prop and ask, “Why did he bother with fiberglass? Why not just cut it out of thin plywood?”
Seashell
With the piece finished, I painted it with a number of metallic paints, as well as a dark wash for the cracks and crevices, and some Rub’n Buff for highlights along the edges.
Stage Directions magazine has a great feature on Faye Armon-Troncoso this month. In “The Actor’s Propmaster“, we get a look at how she got started, some of the show’s she has worked on, and what she has learned. I got to work with Faye a bit when I lived in New York City, including assisting her in the production of Merchant of Venice mentioned in the article.
I love this visit to the Fiberglass Animal Farm. FAST Corp in  Wisconsin is responsible for most of the giant animals and other roadside attractions you see around the US. If you pass a giant ear of corn on the side of the road, it was probably made by them.
Just a reminder that there’s little more than 25 days left to enter the Prop Building Guidebook Contest! You can’t win if you don’t enter. I also wanted to ask a favor; if you have already bought your copy of the Prop Building Guidebook, head on over to the Amazon page (or to whichever store you bought it from) and leave a rating or a comment. I also have a Facebook page where you can tell me what you think. I’d love to hear what you like about the book, what you don’t, and how you’re using it. Now, onto the links!
David Katz has a website with a lot of information centered around his “Chemistry in a Toy Store“. It has some pretty fascinating articles about how common chemical toys work, such as Silly Putty, Slime, Shrinky Dinks, and the like. What is even more useful is if you scroll down, you will see Chemistry in the Toy Store Recipes; Katz shows how you can use common household ingredients to make things like slime, ooze, disappearing ink, various putties and more. Props people need these recipes all the time, and Katz is the chemist who originally came up with most of them.
Phil Obermarck is a sculptor who runs a blog, and he has an in-depth article about his experience using Jesmonite. Jesmonite is a gypsum-based acrylic resin that can be used with fiberglass. Unlike typical fiberglass resin (usually a polyester resin), Jesmonite is water-based and contains no solvents, which gets rid of a LOT of the health and safety hazards inherent in using fiberglass (though certainly not all of them). It unfortunately looks as though it is only available in the UK and Europe, though you can get comparable products in the US (Aqua-Resin being among the more popular).
Photographer Andrew Scrivani has an interesting article in the New York Times on how to choose props to improve food photography. While few of us may be propping a food photo, the ideas he shares are just as useful for anyone dressing a set or designing the props in a scene.
In Thurston James’ second book, he tackles the subject of molding and casting for prop makers in more detail. The Prop Builder’s Molding & Casting Handbook guides you through the most common materials and methods used in many prop shops. Because of its specific focus (and better organization), this book is far more successful than his previous Theatre Props Handbook, which, as I mentioned in my review, meandered through disparate topics with no way to quickly find information.
Though written in 1989, the methods described in this book still hold true today. Though the range of materials we can use today have grown dramatically, they remain improvements and new formulations to older materials whose predecessors can be found in this book.
It remains one of the most widely recommended books for molding and casting props because of the unique niche it fills. It describes the most common materials and methods used in props shops and by hobbyists; these materials are used because of their cost, ease of use, availability, and proven results. Books on molding and casting for manufacturing and industry are more focused on specific or specialized materials, and they aim for a level of consistency and cost efficiency which the prop artisan would never possibly need. Shaving a tenth of a cent off the cost of a casting makes a difference if you are casting ten thousand pieces, but it will be impossible to notice if you are only making ten.
James seems to have had an epiphany in shop safety between this book and the last, as he now presents clear and accurate safety precautions in the beginning of the book, and continues to reiterate them throughout. In his Theatre Props Handbook, safety precautions were nearly nonexistent.
The book does a good job of covering the generalities of mold making and casting. It discusses the model and its preparation, and defines a number of necessary terms, such as undercuts, release agents, mother molds and the like. It describes the considerations of making a mold of your specific piece, and breaks the various molding materials and casting agents into categories. In a way, it describes the process of choosing your materials in an almost flowchart-like manner. If you know what your model looks like, and you know what kind of properties and appearance your castings need, then you can narrow your choices of mold material and casting material down to a few choices. In the book, he describes over thirty of these material choices.
guides you through the most common materials and methods used in many prop shops. Because of its specific focus (and better organization), this book is far more successful than his previous 
, which, as I mentioned in