Clear cast resin is a type of acrylic that comes in large bottles of resin and small bottles of catalyst. To create an item out of resin, you must mix a small bit of catalyst in with your resin, then pour into a waterproof mold. The mold will get warm as the resin hardens, then several hours later, you pull out a hard, clear casting of your item. In this case, I was creating the clear blue blade to the Sword of Light, for my Gourry Gabriev costume at A-Kon.

You can purchase clear cast resin and catalyst at most craft and hobby stores, such as Beverly’s Craft Store.

Step 1: Pattern

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I tried several types of molds for my sword – clay, latex, and so on. Part of my trouble was that I was trying to create a mold from scratch, rather than casting the mold from an item I already had. So, in the end I created a pattern on paper for the sides of a sword blade, and cut it out of a plastic sheet (for the inside of the mold, to give a smooth surface for the resin to cast against, giving nice, flat edges to the sword blade), then balsa wood (for strength for the mold). The strength is important – I tried casting with just the plastic sheet portion of the mold once, and the mold ended up curving under the weight of the resin as it was hardening, giving me a long, curved sword. Looked rather interesting, but wasn’t what I wanted. Next, I glued the plastic to the wood, then glued the sections for each half of the mold together, giving me two large pieces, the front and back of the mold, which would fit together to be cast into.

Step 2: Casting

To make my casting, I used packing tape to hold the halves of the mold together – several layers of packing tape, to prevent leaks. I then used tape to hold the mold point down/open end up inside of a large garbage can, to catch any leaks if they did occur. Be sure that the mold is securely in place, since if it tilts, the top of your mold may spill, and will end up with an angled base to your blade.

I then mixed 1/4 oz catalyst and some food coloring (I wanted a clear blue blade. I later made a metallic blade, using about 1/2 oz of silver enamel paint) in a large measuring cup. After these were well blended, I mixed in 2 cups of clear casting resin, stirring for about a minute. At this point, I poured the mixture into the mold, and poured the leftover into an empty soda bottle, which I then threw away. At the top of the mold, I embeded some wooden sticks into the resin, to give me a starting point when I would later add the hilt. Soon, the mold began to get warm, indicating the resin was hardening.

WARNING – if you add too much catalyst to the resin, it can get VERY hot, possibly melting plastic and burning wood, as well as shattering your casting. Be sure to keep an eye (and a finger) on the mold, checking on it every few minutes. If it feels like it is becoming uncomfortably warm, or if you are hearing strange snapping/crackling, fill the garbage can with water to prevent a fire. Keep an eye on your bottle of leftover resin, too – it can have the same problem.

Step 3: Removing the mold

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A few hours after my mold felt cool to the touch, I removed the halves by cutting the packing tape off, then prying the plastic/wood sections away from the cast resin, which was still slightly sticky.

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At this point, you can use scissors to trim the edges of your casting, to clean up imperfections. I suggest hanging the casting by the sticks used as a starting point for the hilt, so that it doesn’t warp as it dries. The casting will always remain somewhat flexible, and if you store it on a non-flat surface, it can warp. To ship the blade, I suggest getting a large box and using blocks of foam to form a trench for the blade to rest in. Shipping in a tube surrounded by bubble wrap is also possible, but can lead to the blade warping in transport. Should the blade warp, rest it over small objects with some sort of weight on top of it to bend it back opposite the warp (ie, put the bend on top of a DVD case, with a bag of flour sitting on either side of the bend on top of the blade, pushing the bend back out). After a day or two, it should hold the new shape you desire.

Note that at A-Kon, I was required to peace-bond my sword (prevented me from drawing it from the scabbard) because the blade, created as detailed here, was too sharp along the edges. If you are going to go to a convention with a resin-cast blade of this type, I suggest using a Dremel or other power tool to sand down and round out the edges of the blade, otherwise convention security will be unhappy.