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.
Urethane Resin - Liquid Plastic
Molding Compound - Quick-Sil
Disposable Measuring containers
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.