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Step 5Casting the Hexes
I like the one gallon kit of Smooth-Cast 300, the gallon kits come as one gallon of part A and one gallon of part B, to make two gallons of plastic. This goes for the silicone as well. The nice thing about these is that theyre easy to pour. I found that pouring part A into part B (the yellow bottle into the blue bottle) made less bubbles, as part B is a little more viscous than part A. Make sure you shake both parts up good before you use them. This goes for the silicone as well.
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 youd better move fast. There are other plastics that have longer pot lives (and equally longer demold times) if youre 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 formthe 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 arent 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 wont have to make replacements. Ive casted sixty parts from a single mold with no problems. The more undercuts you have, the more wear-and-tear youll 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 (thats what I did). The important thing to remember is to have fun, because this can get real tedious real fast. If youre 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 42x82 sheet of drywall.
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 youd better move fast. There are other plastics that have longer pot lives (and equally longer demold times) if youre 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 formthe 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 arent 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 wont have to make replacements. Ive casted sixty parts from a single mold with no problems. The more undercuts you have, the more wear-and-tear youll 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 (thats what I did). The important thing to remember is to have fun, because this can get real tedious real fast. If youre 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 42x82 sheet of drywall.
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