Mold Making Question

[Malatory]

I am wanting to make a shell type mold, to come out like a bowl. is there a discription on how to do this on the net?

This is for the Spider I am making, I am spinning my wheels and wandering if I can make the shell out of Plastic. I am getting close on being done with the head/body part and the Back Pod area of the spider. That way it is easy to add the computer to it. or Instead of pooring liquid plastic in to it. Would it be easyer to form acrylic / plexi glass over the template piece. I would like to be able to use the form more than once.

example at a smaller scale.
http://www.malatorymods.com/helloween/itsy-bitsy-spider22.jpg

[Bum]

I would think it depends on the ultimate size of the piece. If it is going to fit a computer inside, I'm thinking you'd need at least 12" of interior room (depending on what sort of mobo you're using). I'd think a larger shell would be easier to form in pieces around a solid mold, e.g. warming plexi or laying out fiberglass or for a really smart look, carbon fiber (ala Mashie's Y2K bug). Otherwise, for a pour mold, you'll need to create an outer mold and an inner one to create the inner space. In any case, I don't think you'll be able to form it all at once and come out with any real strength in the legs at computer size.

[Malatory]

Legs I have Covered.. I am looking for all options on the body parts.

Carbon Fiber is out as the Cost of it is on the High $$$ side, and Yes I would like to use that.

Reason I am thinking plastic as Holloween is fast aproching. I might be able to poor 2 and use one for the computer case and the 2nd for a lawn. But I also think I am missing something in how to do it. Unless its just making the form and going though the same process as the mother mold, but 2 lays of Rubber and a gap between the 2 layers. Basicly If I wanted to make a new computer mouse. How would I make the mold for the shell.

[Malatory]

One of my co-workers started asking why no do it a little like they do with putting Ice Cream in Cakes .. Or see if you can find out how they make the hollow easter chocolate bunnies.

We Since I have made Hollow snowmen at christmas time out of white chocolate.. I have some trial and errors thoughts. Now I just need a way to make sure it is the same thinkness.

[Crimson Sky]

Smooth-on.com (http://www.smooth-on.com/howto.htm) has the materials and some good basic info on mold making. If you want a hollow or "bowl" type casting, you can always make a basic one part rubber mold, and then simply brush on the liquid plastic casting material layer by layer. When you have achieved the thickness and strength you want, pull the casting out and you are done.

Reynolds (http://www.reynoldsam.com/products.htm) is also a good source for materials.

[Malatory]

The plastic that I have it from Smooth-on (Smooth Cast 300). So once I make the outer shell mold I should do it like I have done FiberGlass.

/me happy he ask .. thats a lot easier than my 1st idea.