layly
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Post by layly on Apr 14, 2021 22:38:35 GMT -5
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rodak
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Posts: 15
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Post by rodak on Apr 15, 2021 10:16:27 GMT -5
I've done things like this. You need to do a 2-piece mold. Put a layer of clay in the bottom of the first mold box, and press the keycap down into the clay so the bottom edge of the cap is flush with the surface of the clay. Put a couple of acorn nuts or something like that in the clay to form some registrations, which will keep the two halves aligned when casting. Then fill the box with silicone and let it set. Open up the bottom of the box and pull the clay out, being careful not to disturb the key cap in the silicone. Remove the two registration nuts (or whatever you used). . Then thoroughly coat the surface of the silicone mold with vaseline (I've found that the spray on mold release doesn't work nearly as well as vaseline, which is a lot cheaper anyway). Glue a couple of toothpicks upright to the part of the key cap that's sticking up - the purpose for those is to form a path for the resin to fill it up to the top (otherwise trapped air will prevent it from filling up all the way). Pour silicone in to create the 2nd half of the mold, leaving the tops of the toothpicks sticking out (if you have to destroy the mold box to get it apart, that's ok, just build a new one around it with room for the 2nd half.
After the 2nd half sets, dismantle the mold box and carefully separate the two mold halves, and pull the keycap out. Then, when pouring in the resin, fill up the first half, then carefully lower the 2nd half down onto the first half, letting the excess resin squish out the sides and up through the two holes created by the toothpicks. After the resin has hardened, trim any excess that's come out of the toothpick holes, then separate the two halves. Cut off the "toothpicks" from the casting and trim the excess flashing from around the edges of the keycap.
Some of this may be hard to understand. Let me know, and I can elaborate, or provide some pictures.
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rodak
New Member
Posts: 15
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Post by rodak on Apr 15, 2021 10:34:36 GMT -5
Actually, looking at that keycap, there's so much stuff coming out of the bottom, I'm not sure my method would work entirely. Most of the procedure would be the same, but instead of filling the first half of the mold and lowering the second half on, you may need to just put the two together, hold together with rubber bands (not too tight!), and fill the mold through the holes made by the toothpicks, which may need to be something larger than toothpicks to pour resin into - basically, you'll need to create sort of a funnel to pour the resin into, then trim off any excess after it's completed.
I tried the "funnel" method at first, but the caps I was making only had a thin, flat shaft coming out of the bottom, and it didn't work out too well, which is why I came up with the "squish excess resin out the sides and top holes" method. You sometimes have to get creative and go through a lot of trial and error to get it right.
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