Check this out http://www.youtube.com/watch?v=9J4A_nILyIU exactly what you are talking about, without the weight.
Select as Best AnswerUndo Best Answer
Wow that's exactly what i was looking for.
How much detail do you want? Sand casting is simplest, but you can buy or make 3D rubber molds (and the mother mold to support that).
Well, i want to make one of those Easter Island statues like maybe 7 or 8 feet tall and i need to be able to use the mold over and over again.
So you want an 8 foot tall, one ton chunk of concrete (aprox. one cubic yard) waiting to fall on someone? Sounds like a fun party... You have a limited number of choices here. Best bet might be to get a big sheet of thick styrofoam or foam insulation and start carving it into the mold. That way you could form a box and try to cast in place rather than try to move the statue later. Thin casting might be a better idea, so the inside is hollow or filled with something light (like styrofoam). Make the mold two piece, with a space where the concrete will go. Only the visible side would have to be pretty : ) I suggest you do a simple sand casting (dig a hole with a shape and fill with cement) first, maybe a cubic foot in size, just to see what you are getting into.
Haha, I appriechiate your sarcasm, heres a diagram of what I had in mind.
Ok, TWO tons of concrete waiting to fall over. No foundation, on soft soil... How are you going to fill the mold (think 18 bags of concrete mix per statue), lift one bucket at a time over your head? Or are you going to lift the statue into place? It's going to weigh the same as a small car-and no, I'm not kidding. Not sure if you can build a box strong enough to hold at the bottom-look at some pictures of poured foundations or highway construction-those forms are steel for a reason.
All right, all right i probably am misjudging a little.
Did you mean concrete when you said cement? Cement or sand/cement wouldn't be suitable for casting a statue, you would need a concrete mix of sand/cement/aggregate to make it strong. Also a statue that large would need some kind of reinforcing (usually steel wire or bars) to prevent large chunks breaking off and falling on someone. Concrete has good compressive strength (aggregate) but poor tenslie strength (needs reinforcing).
whichever is best, and yes I am going to use some steel bars.