Casting a Small Object: Assassin Symbol





Introduction: Casting a Small Object: Assassin Symbol

About: I'm a maker with a penchant for art and a love of sculpting the unsettling. I also appreciate the history of deep craft traditions and would be a good part of any post apocalypse survival team.

A while back I made a crazy Assassin's Creed costume for Halloween and cast a few assassin symbols for it. Given that my last mold making project was a debacle, I decided to post a basic how to for a successful project. This is about as basic as it gets when it comes to mold making, which also means there are fewer places to mess up. This technique is also good for jewelry or creating anything small that has a flat back. 

Polymer Clay
Urethane Resin - Liquid Plastic
Molding Compound - Quick-Sil
Disposable Measuring containers
Stir Sticks

Step 1: Create the Original

In this case, I used Sculpy to make the original Assassin's symbol. The easiest way to do this is to print out a picture thats the right size and then sculpt directly onto the paper. It ensures that you'll get the right proportions, and you only have to worry about texture and depth. Bake the symbol so it hardens. I left it on the paper when I put it in the oven so it wouldn't bend and distort too much.

Step 2: Quick-Sil Mold

Quick-Sil is super easy to use since it's just two kinds of putty you can mash together. Don't over mix it. It should look marbled, but more of pencil line marbling. I had one vein that was too thick and never set properly.  

Next, just push it onto the hardened object making sure to fill in all the details. It's a little harder than play dough and pretty malleable. Also, attempt to get the back as level as possible since that will be on the table when you cast. 

I like Quick-Sil since it's reasonably priced if you're using it for small objects. The 3oz set should be under $10. Anything larger than this symbol and you'd be better off using a different silicon or latex mold material. Both of those are a whole other animal that I won't get into, but I'm assuming someone else on this site has done a fantastic job covering. 

Step 3: Pour in the Plastic

After your mold has set up, which should take 15-20 minutes, you can remove the original and get casting. Be sure your mold is on a flat surface and if the back of it isn't level, you may need to put small pieces of clay under the edges to level it out. 

I used Smooth-On Liquid Plastic - Smooth Cast 300. Make sure you have cups with measurements on them and lots of stir sticks. Put on your safety gear and measure out the two parts in equal amounts. With something this small, you won't need much at all, so be precise with your measurements. It's starts to set up after about a minute so you'll need to work quickly to fill the mold. Wait 10 minutes and it should be fully set up. I tried tinting it, but the color never came out right for this project, but for other objects it might work well. 

Safety note: Resin is toxic when it's curing, so be sure to open the windows and wear a respirator and gloves.

Step 4: Paint

I tried several different combos of tinting the resin and just painting the plastic. I got the best results from painting it black, letting it dry and using some rub on silver metallic wax.

There you go! Now you can run off into a leap of faith with your new found power of the Assassinos. Or broaches, earrings or whatever lovely items you made from the process.  



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    Oh I thought that was actual metal! It's very cool though!

    1 reply

    Yeah, me too! Great job

    Most larger art supply stores will have a mold making section. If they don't have the brand quick-sil, look for the phrase RTV silicone putty and it will be the same thing.

    Great instructable! Question about the SmoothOn resin that results - how firm/bendable is the result? Could you break it? I've read about their products for years but never got around to trying them yet. Super curious.

    2 replies

    Thanks! So when the plastic is thicker than, say, a half inch, it's rigid and pretty hard to break. Since this object is fairly small and thin, it could break if you really pull on both sides with a good force. You hear about SmoothOn products because they are so widely available at craft and art supply stores. There are other brands like Douglas and Sturgess, which I love since they are a brick and mortar place and are great about answering questions, but they are also pro level and with so many products, I get confused unless I know exactly what I'm looking for. Good luck with your project!

    I haven't actually tried the SmoothOn yet, but I've been asking questions of how to make molds/products of people for a few mos now, and I keep hearing SmoothOn. Gotten referred to that by at least 5 people so far, so guessing its pretty snazzy. ;)

    Very cool. I'd love to see the full costumes. If you don't mind I'd like to add this to Assassin's Creed collection I created.

    2 replies

    Add away! I'm putting up the full costumes soon, just have to take some photos. What's the link to the collection?

    Very cool, can't wait to see them. I'll add them to the collection as well.

    Nice! Once you've got your silicon mold, you can also fill it with wax and do lost-wax casting in your metal of choice. That's a totally different instructable, though ;)

    Oh wow, this is exactly what I needed. Thanks so much!

    You're smart to get SmoothOn materials in the sample sizes. Why do you want the silicone to be marbley instead of all one color? I might have dusted the mold with aluminum powder before pouring the resin. Nice job.

    1 reply

    Thanks! For this product, the silicone doesn't set properly if you overmix it. Good idea to use aluminum powder. I'll give that a whirl next time.

    Great tutorial - the piece looks fabulous!

    Question ? Are you going to mass produce this ? I'm confused at why not use the clay that you originally molded ..

    This is really a question not a diss.. Trying to figure all this out for my kids costumes :$

    2 replies

    Good question. I didn't quite mass produce, but I did make two costumes (Connor and Aveline from AC3) and needed 6 or so of the symbols for different areas. Also, I wanted something a bit more sturdy since polymer clay can get brittle when it's thin. And finally, and most importantly, I had all the stuff in my studio already. If you're only making one or two though, it's probably the smart move to just go with the clay.

    i believe it is because they need somewhere to pour the liquid plastic into, and it is far easier to mold what you want then make an indentation to pour the plastic into to set.