3D Printers: From Screen to Thing

The first task at hand, now that I've got the plane situated, was to start building the instruments. I've had most of the design work carefully completed several months and in one case 8 years in advance. The original plans by Mike Powell, did not include provisions for the bezel ring, or at least the raised ring portion. About a year ago, I took measurements based on photographs and produced a CAD file. For whatever reason, I never printed it out, maybe I wanted to wait until I had an actual instrument to compare too. When I bought the plane, I purchased a few broken instruments, including an ADF. Strangely enough, the ADF won't fit in my aircraft without removing the knob, so I had to install it sideways. Anyway, after comparing measurements, I was surprised to learn that my rough estimates were actually pretty close, so I took my design down to NextFAB Studio where I could reproduce my design on a 3D printer at no cost. The next day, I installed the prototype in the panel and found that it fit perfectly!

It took about 2 days to prepare a silicone rubber mold. After a good 16 hours of curing, the mold was ready to use, and I made my first pour. The castings only took about 15 minutes to cure enough that I could take them out of the mold, so on my first night, I made 6 castings. When they come out of the mold, they are solid but still plyable. The next morning, they were hard as a rock. A quick clean-up with an exacto-knife to remove excess was all that was required.

I put together one of the castings with a proxy instrument face and the etched compass face that I had made last year on a laser engraver. Once installed into the panel, the look was very convincing. The only obvious difference is that the real gauge was showing wear and tear with aluminum showing through it's painted surface. My cast instrument bezel ring was cast in black, so the paint will never rub off.

Resources:

CAD Software: Solidworks 2013, usage provided by NextFAB Studio (www.nextfab.org).
Instrument Design: Overall design based on plans in "Building Simulated Aircraft Instrumentation" by Mike Powell (www.mikesflightdeck.com) with extrapolations for the ring made by me from various photos online.
3D Printing: Completed by me on a RepRap 3D printer, usage provided by NextFAB Studio.
Casting Materials: Smooth-On Silicone Rubber Mold Liquid and Smooth-On Off-White Casting Resin, purchased at www.inventables.com. Black casting pigment purchased at www.smooth-on.com.

Bezel Ring Prototype

Trial Fit. Note actual instrument on left.

Making a rubber mold.

Reproductions: Just add goo

On the left: A mock-up with a cast bezel ring.
On the right: A real instrument for comparison.