Materials you will need:
Clay or other modeling compound (I prefer polymer clay, it stays hard until you bake it)
Sculpting tools (dental tools are nice for real small details)
2 small strips of thin wood (1/4"x2x4 poplar was what I used)
rubber or latex gloves
silicone compound (I used Smooth-On's Oomoo 25)
plastic compound (I used Smooth-On's Smooth-Cast 300)
Mold Release (I used Mann's Ease Release 200)
4" pvc pipe joint
sandpaper (progressively finer grits recommended)
Spray paints( automobile primer, different colors for the base parts, clear matte coating)
Airbrush (strongly recommended)
enamel paints (I used Testor's from a hobby shop) and brush cleaner
cotton swabs, tissue paper, and paper towels are nice for cleanup work
Step 1: Sculpting Original Hexes
When you have enough rolled out (each flat hex took me a little more than one package of FIMO), use a cardboard hex from the game to get the shape right. I cut down with a straight knife then baked the flat hexes. This made sure that anything I add to the hex doesn’t mess up the shape of the base. Be careful and try not to leave fingerprints on the pieces like I often did, they will show up on your casted pieces!
The more time you spend on this step, the better your set will look. I am definitely not a sculptor, and even pieces that don’t look that great sculpted can look real nice after you’ve painted them.
The great part about this is if you dont’ like it, add more clay and try again. If you get something you really like, bake it hard. You can still sculpt and sand the pieces after baking, but it’s tougher to get what you want. Every little bit of texture will transfer to your casted pieces, so the more work you put in to smooth or rough areas, the more rewarded you will be.
Be warned that undercuts may complicate your molds and cause more wear and tear than they’re worth. The materials I used were fairly forgiving, but I have two molds that started coming apart after about 20 castings.
Step 2: Additional Supplies
The two important things to remember here are: one, make sure you measure as accurately as possible each of the silicone liquids. Too much of either one and you’ll have stuff seeping out of your molds. Two, make sure you mix the two liquids completely. It’s got a long enough pot life, so spend the extra minute or two mixing the silicone.
Take a couple of plastic cups, put one inside the other and pour 1/4 cup of water in the top cup. mark the side of the bottom cup at the level of the water. Repeat for 1/3, 1/2, 2/3, 3/4, and 1 cup. You must have large cups to mix 1 cup of each liquid. Plus, the silicone gets harder to stir properly with plastic utensils when you have that much liquid. Remove the cup with the water in it, put a new cup in and measure parts A and B (in different cups). You can reuse the “measuring cup” until the project is done. Sorry about the dim picture, this one was hard to get with a flash. Look closely towards the bottom of the cup.
Step 3: Pouring the Mold
The great thing about this stuff is it’s simple to work with in a 1:1 by volume mixture. The silicone is pretty fluid, but you should still be careful about bubbles. Pour your silicone mix into a 4″ PVC pipe joiner with the original face up at the bottom. My pipe joiners weren’t smooth at the bottom, so I sealed up the edges with clay to keep the liquid silicone from leaking out. Some people make their own mold boxes for this step, but the PVC worked great for me.
If you get the gallon kit of Oomoo 25, make sure you pick up some cheap plastic measuring cups, preferably with a looped handle, as the gallon kit of Oomoo 25 comes as two buckets. This is not something that pours easily. Your arms will get tired if you try to make too many molds at one time, you really have to put some elbow grease into mixing the silicone (the plastic is much easier!).
Pour the silicone into your mold. I found pouring into the lowest part of the mold and letting the level of silicone rise up and over the original works great. If you have some undercuts, you can brush the silicone on around the trouble areas and then fill slowly. I never bothered with this, as my undercuts weren’t very big. Make sure you pour enough silicone to completely cover your original, then give it another 1/2″ at least on top. A little more won’t kill you, and your mold will last longer. I found that a little post-molding cleanup is also necessary. Cut away any unwanted silicone with a small sharp hobby knife. You can continue to alter your model by carving the silicone, but that’s pretty crazy and I don’t suggest it.
Step 4: Cure the Mold
Smooth-On recommends heating the silicone to 150 degrees Fahrenheit for four or five hours to evaporate leftovers from the silicone mixture. I did this for all my molds, so I don’t know what happens if you don’t. Make sure you keep everything around room temperature and that you use up all the containers that you open because they have a limited shelf life after you start opening and closing them.
I tied some string to each of my measuring cups and left them in the A and B buckets, with the string sticking out, held down by the lid so the cup didn't sink to the bottom of the bucket next time I needed it.
Get some silicone mold release. I’ve read that talcum powder works, too, but I stuck to the manufacturer-recommended release. I used Mann’s Ease-Release 200, one can goes a long way. Spray your molds every 3 or 4 pieces to preserve the life of the molds and ensure the easy removal of the casted pieces. It’s best to let the release agent dry, but in all honesty most of the time I just sprayed and casted again. It leaves a sheen on the casted part, but it didn’t appear to hurt anything. Especially after I painted the pieces.
Smooth-On’s website also suggests spraying primer into the mold after the release agent dried. When you pour your plastic, it supposedly comes out bonded with the primer. I did not test this, although I am still thinking about doing it in the future. The problem is you have to wait for the release to dry, then the paint to dry, before you can cast parts—not good if you’re making a lot of small pieces.
Step 5: Casting the Hexes
There are many brands of silicones and plastics, and each manufacturer is guaranteed to have many different types, so the choice is totally up to you. They should offer sample kits (Smooth-On did), they're a great way to try out a material before you commit to it.
Smooth-Cast 300 has a three minute pot life, which means you’d better move fast. There are other plastics that have longer pot lives (and equally longer demold times) if you’re worried about your time. You definitely have to work quick.
When you mix parts A and B, you will introduce bubbles to the mixture. But try not to anyway. Pour your plastic into the mold the same way you poured your silicone. If you have places where bubbles form (typically around undercuts), direct the stream of pouring plastic right above that spot, and it may force the air bubble out. When this is not enough, use a blunted toothpick to push the bubble until it comes away from the mold and rises to the top. Try to pop the larger bubbles that may form—the smoother the surface the easier your job will be later.
Did I mention you want to do this on a level surface? How about casting plastic in a well-ventilated area? These are both important. The plastic fumes aren’t very fun to breathe in. The plastic solution also heats up as it cures, and is fun to watch. Parts A and B are both pretty clear (A has a slightly yellowish tint), and when mixed, they remain clear, but as the start to cure, they turn a bright white color.
After the plastic has had time to cure (about 10 minutes for Smooth-Cast 300), gently bend the mold and ease the piece out. Marvel at your power of duplication. By being careful and spraying mold release every few parts, your molds will outlast your project and you won’t have to make replacements. I’ve casted sixty parts from a single mold with no problems. The more undercuts you have, the more wear-and-tear you’ll see. I have one mold (my second forest hex) that started breaking because of the undercuts after about twenty pieces.
Repeat these steps to make as many parts as you need. Make a couple extras. Make a set for yourself. Make them for Christmas gifts (that’s what I did). The important thing to remember is to have fun, because this can get real tedious real fast. If you’re making a lot of parts, make sure you have a nice big area to put them. I had a big stack of drywall in my garage where I put them. I made enough hexes to almost completely cover a 4′x8′ sheet of drywall.
Step 6: Cleanup and Painting
Spray on a base color. I chose to use normal spray paint for this part, and it worked pretty well. I used a different base color for each different type of terrain to make it more easy to identify when playing Settlers of Catan. Since I created two different sculptures for each terrain type, this reduces confusion. I tried to keep them close to the color of the original Catan resources, red for hills, gray for mountains, yellow for fields, etc. When the paint dries, you’re ready for the real work to begin.
I used enamel paints from Testor’s, they have a decent selection of color and were the only enamel paints my local craft shop had anyway. This next part is real important: beg for, borrow, or steal an airbrush—I promise you won’t regret it. An airbrush not only turns an art-challenged person like me into a pro, it also uses less paint doing so! Also get some newspaper to put down, some paper towels, cotton swabs, and a few different-sized brushes. Don’t forget plenty of brush cleaner.
Fire up your airbrush and pick a color. Don’t be afraid to experiment! I was really overwhelmed at the beginning and didn’t know where to start, so let me make a recommendation: grab a nice brown and spray it around the middle of your mountains. Move on to any other parts that may need brown to cut down on the number of color-switches you do with the airbrush. I hate cleaning those things. Switch to a foresty-green color and spray the base of the mountains, then add white to the top. That’s all I did here, and it looks pretty nifty. Add a final two coats of clear matte coating and you’ll be ready to play!