Printing and casting a linked stars light

I really like the linked stars shape I created with TopMod, I wanted to make a big one and put a light in it. I made a few different varieties and picked one that was printed small to see if the shape would be ok. The guys at Protospace printed some of the other varieties that ended up in the christmas tree, I was pleasantly surprised to see these also in real. The shape I made in TopMod, was cut in and further modeled with connectors in FormZ. This shape essentially consists of one shape a five armed star that is connected to each other, only to fit the parts together I had to make a small connector where the arms would connect.

At ProtoSpace Utrecht I printed the star as large as the printer allowed 20cm in diameter, this would result in a total size of the light of 40 cm when finished. The printed parts were sanded and made really smooth, the connection parts were adjusted so they had right the tolerances to fit nicely together.

Because of the size and shape of the part I had to make a thin two part mould with two support moulds to make a nice parting line, save on silicon rubber and to easily de-mold the thin casted parts. Then twelve stars and twenty connector parts were casted in white resin and put together.

The small printed example part 5 cm diameter

I wanted to make a multiple parts mould but it turned out too difficult so I decided to make it simpler

First the base was created from clay, the support moulds were made from this. I used PlastiPaste (Smooth-On) for the supports.

Here the two support moulds are created and the printed part fits like a glove.

The first thin mould side is casted, the red dots are made from clay and are removed before casting the second half of the rubber mould. These make the mould parts fit exactly together.

The middle wooden stick is for the resin in flow The sticks on the outside are to de-air channels at the highest point. The resin starts to flow in at he lowest point and will fill the mould without air bubbles.