Achromodic Update 4/11

I've been working on an idea for the back panel, but had to scrap several failed attempts, mainly due to 3D printing woes. But now that I revised my plan, redesigned the model, and fixed my printer, I finally have a workable piece!

The idea was to fill the center of the back panel with a bunch of random, extruded, clear organic shapes that will be backlit by the 140mm fans. Simple enough! ...well not really. :P

First, I had to come up with a 3D model, so I created a cluster of organic shapes derived from the webbed motherboard tray and fan grills. It's basically a reverse of that, in where the holes are now the solids. I then designed the cluster to be stackable end to end, making a seamless pattern so I could stack four of them to fill in the back panel. Here is the 3D printed quarter section:

It fits nicely in the frame of the back panel.

In order to make duplicates of this in clear resin, I need to make a silicone mold of it. So first I coat it with XTC to smooth out the print.

While that cures, I whip up a quick box for the mold.

Doing some volumetric calculations, I realize my box is too big for the small amount of silicone I bought, so I used some dense foam pieces to fill in around the print. Now I should be able to cover the entire piece without running out.

I'm using a product from Smooth-On called OOMOO 30, which is a 2-part silicone rubber. Very easy to work with, just mix both parts 1:1 ratio. Working time is 30 minutes, cures in about 6hrs. .. but why do I feel the need to play Portal 2 now? :P

Once mixed thoroughly, it turns to a uniform purple color. Some products require the use of a vacuum chamber to degas the mixture (remove all the bubbles), but this OOMOO stuff is formulated for beginners and doesn't really need it, due to it's low viscosity.

After spraying on some mold release, we're ready to pour! Going around the edges with a long slow pour and letting the silicone flow into the piece by itself helps prevent any bubbles from forming.

Now we wait while it cures.

The next day I came back and started the demold process. I quickly found out that it was going to be impossible to get the print out in one piece. I could work it loose all around the edges, but the center was locked and I was starting to tear in places in between the towers. So I had to cut around each one and remove them one at a time.

All out! Didn't take too long, but now I have to rethink my plan of making a resin copy all at once, because I won't be able to get it out of the mold in one piece. I will have to divide it up into smaller parts, or even do each shape individually.

Next update will hopefully show some successful resin replicas of the original print. Fingers crossed!

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