Mold Making?

So, after making this awesome isntructable (it's curing now!), I got ideas for other concrete projects. My favorite so far is making a concrete lamp. I want to make a mold of a lamp (light bulb in it) and then cast it in concrete. I'd then put a real lampshade on it and call it art. My problem is...I have no mold making experience. Do you guys have any tips, know where to get silicone, etc?


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treg9 years ago
Hi, I'm actually writting an instructables about how to make a lamp with concrete, optic fiber, and leds. It won't help you with molding, but maybe we can share ideas / reviews. Just send a message if you want.
Rishnai9 years ago
Plaster of paris is my favorite for small-to-medium molds. I'm not sure if I'd use it for a lamp, though. Using your mortar mix might work, and when it's dry, putting a coat of acrylic and then waxing it would make it easy to use as a casting mold. If you want, you can use RTV gasket material from the auto parts store to make a mold, but bear in mind that this stuff is thicker than the mold-making sort. A little birdie told me you can get the moldmaking sort at most craft stores.
NachoMahma9 years ago
. You may be able to get a glossier finish by powdering the inside of the mold with concrete dust before pouring. . You should be able to find silicone grease/spray/&c at most industrial electrical/electronic outlets.
Weissensteinburg (author)  NachoMahma9 years ago
What about the silicone itself?
I've always wondered where to get silicone, too
They use a lot of silicone in make-up effects etc - try a local theatrical suppliers.

Online, try looking for alginate - like this stuff (that's just an example, not a specific recommendation).

There's more information here and this company seems quite relevant as well.
Kiteman Kiteman9 years ago
Oh! That last link offers free shipping and reduced prices for first-time buyers in the US. (link)
Weissensteinburg (author)  Kiteman9 years ago
Hmm, the website seems to only sell in bulk, unless I'm missing something. That, or prices in the $500's are normal.
Ah, well. At least it gives you something to look for. Unless you can talk a sample out of them?
Weissensteinburg (author)  Kiteman9 years ago
Do you think clay could work?
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