geekhack
geekhack Projects => Making Stuff Together! => Topic started by: Equorial on Mon, 28 January 2013, 23:25:34
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I'm planning on making some keycaps to preoccupy my time. Problem is, I can't get my hands on silicone rubber easily. Is there any other (inexpensive) material I can use for molding? I plan on attempting 3D models as well. Help would be greatly appreciated.
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You can make a mold out of almost anything, but resin is a common material.
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Resin is the casting material. That, I can get my hands on pretty easily. It's the silicone rubber meant for the mold that's difficult. Beyond it being expensive, there's a limited number of places in Toronto selling it. I can't even buy it online because I don't own a credit card. I was thinking that I could use plaster of paris but I'm a bit iffy because I'm afraid that the stem would break before I can even make the positive.
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If you use the two part casting method which is in here (making stuff together) somewhere, then you shouldn't have any major problems with paster, make sure that your cap is well lubed with vaseline or similar otherwise it'll bind to the plaster.
Plaster is harder to degauss than silicone so you may struggle to get a bubble free finish unless you have access to a vacuum chamber, but a little filling and sanding can fix that - depending on the complexity of the cast.
If you go to complex, then plaster stops being an option due to the brittle nature, and silicone with its elastic property becomes the only option - other than one off casting, smashing the wax to get at the finished cast cap.
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Resin is the casting material. That, I can get my hands on pretty easily. It's the silicone rubber meant for the mold that's difficult. Beyond it being expensive, there's a limited number of places in Toronto selling it. I can't even buy it online because I don't own a credit card. I was thinking that I could use plaster of paris but I'm a bit iffy because I'm afraid that the stem would break before I can even make the positive.
You can make your molds from the same material you are casting (it's done quite often in fiberglass), you just have to be vigilant in ensuring you adequately cover everything in release agent.