Have you ever tried pure silicone that you put in a bowl of soapy water? I make a lot of my jewellery molds like this and I love it - it cures really quickly and lasts forever :D All you have to do is knead it under the water until it starts to get thicker and denser then all you have to do is form it in a ball, roll it out and press your items in it. I haven't tried it, but I bet you can cut a plastic cup in too, stick the top of the cup down, and pour it on top of the object. If you do this I would think that you shouldn't knead it as much so it's still soft enough to pour it over.
By ShakeTheFuture
Have you ever tried pure silicone that you put in a bowl of soapy water? I make a lot of my jewellery molds like this and I love it - it cures really quickly and lasts forever :D All you have to do is knead it under the water until it starts to get thicker and denser then all you have to do is form it in a ball, roll it out and press your items in it. I haven't tried it, but I bet you can cut a plastic cup in too, stick the top of the cup down, and pour it on top of the object. If you do this I would think that you shouldn't knead it as much so it's still soft enough to pour it over.