Tag Archives: acrylic

Rupees from Legend of Zelda

For the last few weeks before I came out to Santa Fe, I was building some props for a local theatre group known as The League of Extraordinary Thespians. They are doing a musical of The Legend of Zelda: Ocarina of Time. The first props I finished were the rupees, which are a type of jewel used in the game to buy items (some of you may have already seen these in an Instructable I posted last week. Sorry).

I figured the best way to make a translucent gem was to vacuum form the shape. You remember my ultra-cheap vacuum former, correct? Before I could use that, I would need a form. I decided to do the front and back of each rupee separately, and then glue them together. So first, I would need to cut a piece of wood into a rupee shape.

Wood form
Wood form

You can see I’m using the (oddly-named) GRR-Ripper from Micro-Jig; it makes accurate cuts on tiny pieces in a safe and straight-forward manner. I did all the cuts with my table saw, giving me a pretty clean-looking rupee half.

Vacuum formed half
Vacuum formed half

I got a sheet of clear acrylic from Hobby Lobby. They only had it in one thickness; I’m not sure what it is exactly, but it’s less than 1/16″. I started vacuum forming the halves and trimming them out, leaving exactly what you see above.

Painted green
Painted green

Before gluing the halves together, I painted the insides. This way, the paint would never wear off, no matter how much the actors handled them.

For the green ones, I tried watering down acrylic paint. It was pretty tricky, since the paint kept wanting to bead up. Normally, you would lightly sand the surface of the plastic to help the paint adhere better, but that would kind of kill the “translucency” effect. So I bit the bullet and bought some blue and red spray paint so I could just lightly dust the other rupees.

Rupees
Rupees

I used a solvent-based glue (Amazing Goop) to glue the halves together. The glue was a bit thick and dried flexible, which helped make a stronger bond since the edges didn’t quite match up exactly.

And that is how you make a rupee!

A Grand Wedding Cake for Cloud 9

We just closed and struck Cloud 9 here at Elon University. I was the prop master on the show and built a lot of the pieces. One of the fun (and funny) props I constructed was a grand Victorian-era wedding cake. It was meant to be a bit over-the-top, with a grand appearance at the end of Act One when the hastily-arranged wedding occurs. Part of the visual humor came from the cake toppers; the scenic designer (Natalie Taylor Hart) wanted the groom to be a detailed representation of a man striding atop of a Royal Orb, while the bride would be a much smaller and crudely-made figurine stuck in the cake as an afterthought (the play, for those unfamiliar, deals with gender politics in various degrees).

Sculpting the Cake Topper
Sculpting the Cake Topper

To make a sculpted figurine of the groom, I started off with bending a wire armature into the pose I wanted. This also let me establish the proportions of the limbs. It wasn’t anything fancy; I cut up a wire hanger and held it in place with plumber’s putty. Plumber’s putty is a type of epoxy putty which is soft and shape-able when you first mix it together, and becomes rock hard after a few minutes. I liked it on this project because I could build up the sculpture bit by bit, allowing the parts to become hard as I worked on other things. I could return to the sculpture later and add more bits without worrying about smooshing the parts I already made. It also did not need to be fired or coated to finish it. The putty I used was left over from another show, so I did not have to spend any more money on a show with a tight budget.

In the last frame of the picture above, you can see I added some clothes. The putty is not very good for getting fine details; you can machine and carve it after it has hardened, but I wanted a quicker way to get some semi-realistic clothing texture on top. I took muslin and soaked it in glue and water, than manipulated it over top until it “draped” like a shirt and pants. After the glue dried, it retained its shape.

A Grand Wedding Cake
A Grand Wedding Cake

The rest of the cake was pretty straightforward. The bottom base is a strip of wiggle wood wrapped around plywood formers, while the top is a solid chunk of white bead foam coated in joint compound. I used painter’s caulk for the icing details. Normally you want to use acrylic caulk rather than silicone caulk, because silicone caulk does not take paint. However, I found some newer stuff which is a mix of acrylic and silicone; the acrylic makes it paint-able, while the silicone keeps it a bit flexible and lets it dry a lot faster. I bought a few decorative cake icing tips, and just attached them to the end of the caulk tube so it would come out all fancy.

Some Confusions in the World of Plastics

I’ve been researching the wide world of plastics for the book I’m working on. I’m trying to make sure my terminology is correct, and it’s proving daunting; plastics is a world where many terms can refer to the same thing, and common-use terms may not be technically correct. Add to the mix a bunch of trade names which are used generically, and you end up with one big confusing mess.

Take urethane rubber for instance. If you are into molding and casting you may have used it. “Urethane” in this case is a shortening of “polyurethane”, the same kind of plastic you use as a clear varnish among other things. “Urethane” is also a specific substance in the world of plastics; it is known as “ethyl carbamate”. Polyurethane does not contain ethyl carbamate, nor is it made from it.

Rubber can refer to a material or a substance. The substance, sometimes clarified as “natural rubber”, has historically been derived from the latex tree, though the proliferation of latex allergies has led to some companies experimenting with different plant sources. Synthetic rubbers, such as nitrile, do not contain latex; the “rubber” in their name refers to the fact that their properties mimic natural rubber. Technically, they are all referred to as “elastomers”.

Thus, “urethane rubber” contains neither urethane, nor rubber.

Speaking of latex, we all know and love latex paint for painting houses both inside and out. Sometimes we even use it to paint props. It does not actually contain any latex. It refers to paints which use plastics as their binders, such as acrylic, polyvinyl acrylic, styrene, etc. Vinyl resins are cheaper than acrylic resins, and most house paints contain a lot more vinyl than acrylic, which is why pure acrylic paint is a lot more expensive than house paint.

In case you are wondering, the acrylic in paint is the same acrylic found in sheet form, known commonly by trade names such as Plexiglas and Lucite. Crazy!