Lost wax casting, making prototypes.

I have been trying to design a few items that can be replicated. One way to do this is to make a rubber mold. The mold is then injected with wax under pressure and the waxes are attached to a tree (a thicker wax rod with a pour spout). These waxes are invested in a plaster-like substance that is fired in a kiln at varying temperatures to melt out the wax and be ready to accept molten silver to fill what is now voids. It’s a time-consuming process that takes over twelve hours to complete.

For my designs, I have been drafting and 3D printing in resin, as I can get high detail. I then cut up mold rubber to fit around the 3D printed object with a sprue (a channel that accepts the wax) It’s like plumbing the wax needs an entry and needs to flow into the mold where the once object was placed.

The rubber is in layers and vulcanized by being heated under pressure in a metal frame. Once sufficiently fused. You take the hot rubber and cool it just enough to work on as it is easier to cut open while hot.

Working with scalpels and the hands of a surgeon the mold needs keys cut into it so that the two halves interlock and don’t just slide apart. The model also needs care in how it is cut out for the best release of what will be waxes coming out. Air vents need to be carefully placed to get the wax to flow into all areas to avoid cooling prematurely.

On my 7 stones ring I designed the prongs too short, but they injected well. Prongs can be cut to size so I made them longer.

This however posed a problem as all 28 prongs need to come out perfectly to be a success and even one missing is a failed injection. I had trouble injecting these and I really like this design and think it is worth pursuing. I plan to try the prongs in-between my last two attempts. If it is still not working I will then have to move on, this is all part of the learning journey and prototyping.


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