What does your original look like? What's it made of? Will the mold have undercuts?

madhabitz,
Actually I guess I don't have an original. I'm just realizing that a positive mold out of pop probably won't work since I think the mixture is too runny??? (I've never used it before!) I wonder if paper mache would work to form the positive mold then latex for the negative. Any suggestions?? Not sure what undercuts are - I'm very new at this!

Silicon costs more but will last longer. I believe it is running around 60+ per gallon.

Latex will be fine too.

If you make the original model from hypertuffa... it will save you the work of making a mold and support shell.

To see what a variety of latex molds look like, ebay has plenty.

You know, I was thinking of just making the original from hypertufa without a mold. Would this work? I've never made anything yet from tufa so I don't know what king of consistency it has. It certainly would be easier!! Do you know if I could carve the hypertufa form to add extra detail if needed? Would I do this before it cures or after? Thanks!

Basically YOU select the consistency. The less water you have, the less "runny" it will be. With peat moss in the mix, a "moist cow patty" constancy for example would be very formable/ sculptable. You can also fill in detail, smooth in with a slurry later after it has set a couple days.

So it sounds to me like you don't really want to make a mold as much as you want to build a sculpture, right? What about creating a wire mesh armature first, using metal lath or chicken wire, then coating it with one of the cement recipes? I'm really new at this, but there are a lot of threads in this forum and others that talk about this method.

Nancy