Mold Making

[EricofAZ]

Anyone have any experience with making molds? I'd love to see a thread on this.

I have been looking at some high tech ideas that are getting a bit more in line with some hobbyists budgets.

There are a ton of computer graphics programs on the market that can be used to make a polygon mesh of a dolphin or person, etc. Then posed into a position you like. Then the mesh can be sent to a rapid prototype machine that can build the object in something like wood (subtractive) or plastic (additive) and use to make a mold. Either process of subtractive or additive can be made in positive or negative, so coming up with a master for a mold is pretty easy.

I was thinking that it could be an interesting process to come up with whatever object you like and pose that object (preening dragon?) and then make a mold for either an embed or tart or maybe even a pillar.

Modeling the object and getting it to a rapid prototype machine is the easy part for me. What I don't know much about is material selection (silicone is the easiest) and what people's pet peeves are about the molds they buy.

[Miadrianel Candles]

Wow!

My kind of topic. Although I haven't worked with any typenof machining I read about 3d printers all the time in Make magazine.

I also would like to make my molds I have some crazy ideas for candles that would probably be more sculptural than anything I gues. More like what you mention. I have also thought about printing the wax itself in 3d.

Only problem for me is that I would have to get All the stuff to make molds metals, soldering equipment, cutting and all the other stuff that goes with handling sheet metal. And this is just for basic molds.

[EricofAZ]

I looked at 3d printers at the SIGGRAPH 2010 computer graphics show (I go almost every year) and using candle wax is probably not going to work. I think Roland makes a printer for $9K that "might" be able to use candle wax, but you get one print per print head (expensive) and it really isn't feasible.

Most of the additive printers use heat, which makes the candle wax turn to a liquid and you get a blob if you try it.

There is a guy (I'll find his website when I go through my stuff) who has free plans for a $700 build your own subtractive machine that uses a high speed dremel and it does compound curves pretty well. He showed me a wood and a foam block that were cut into leaving a perfect area to fill with silicone to make a mold. What caught my attention is that it was able to cut in a square smaller than the block size with a dinosaur head protruding (subtractive process, positive image). The computer graphics process to make this was to use a dinosaur model and boolean it into a cube then size the cube less than the block that you use.

Pretty easy stuff for CG (Computer Graphics) folks to do. Then when the dremel cut the image into the wood or foam, you just pour in the silicone and you have half your mold.

Flip the image around in the CG program and re-cut the block and you have the other side.

How to mate the sides or use them is what I am not familiar with.