Those of us with 3D printers have had two major choices when selecting a material to print with – ABS, a very hard plastic, and PLA, a more brittle plastic with a lower melting point. [Alex] and [Luke] have been experimenting with printing polycarbonate and creating clear crystalline objects on a standard 3D printer.

The first foray into printing polycarbonate didn’t go so well for [Luke]. Objects came out looking very milky and there was a bit of popping during filament extrusion. The guys solved this problem by putting the polycarbonate filament in a food dehydrator overnight to get rid of the moisture. Polycarbonate has a higher melting temperature than other plastics – around 260 degrees Celsius – which can cause some problems with Teflon insulators in the hot ends of extruders. The guys didn’t have any problems with fumes, though.

If you’ve ever wanted to print something clear, it looks like it’s now possible. Check out the video after the break to see a Makerbot Thing-O-Matic printing with clear polycarbonate.

[Rich] couldn’t find any instances where RepRap owners had used polycarbonate as a 3D printing source material. He’s filled that knowledge gap by running multiple polycarbonate printing tests. Polycarbonate is a plastic that is highly resistant to shattering yet it’s still rather soft. With enough effort it can be bent and stretched, but it’s fairly difficult to break the material.

The test spool of polycarbonate was special ordered for this project. [Rich] sourced 1.6mm filament since 3mm material would have been difficult to spool. It melts at a temperature range of 280-300 degrees Celsius, which he reaches with a hot-end extruder design. The printed material comes out a bit cloudy, which may be due to the heating process itself, or due to extruder reversals (he’s not quite sure what’s causing it). But as you can see above and in the video after the break, it’s certainly a viable printing medium.

[Thanks Marnargulus]

Here’s a Blade Runner umbrella build that is done just a little bit too right. It delivers a double-dose of geekery with its lightsaber-gone-rain-protector look but where we think it crosses the line is at the built-in audio system. When you turn it on it plays recordings of popular lines from Blade Runner, something that might not fly in public. But the quality is in a different galaxy compared to the dollar store illuminated umbrella that we looked at last year.

[Erv' Plecter] replaced the central support rod for the umbrella with a clear polycarbonate tube. An optic cable snakes through the hollow tube, illuminated by a Luxeon LED in the handle. The custom PCB and 900 mAh battery are both housed there as well. Take a look at (and listen to) the demo after the break. We’ll need to add this to our future projects list right after that Lightsaber movie replica build.

[Amnon] is learning the hard way that water and electronics don’t always like to play nicely together. He’s been working on creating a swimming fish that uses three servos to flex a sheet of fish-shaped polycarbonate. This photo doesn’t really do the project justice but you can get a better idea of what he’s accomplished by watching the videos after the break.

The three servos along with some distance sensors for obstacle avoidance are all controlled by a PIC 16F877A microcontroller. [Amnon] tried out three different waterproofing methods; coating the device in varnish, dipping it in hot glue, and dipping it in epoxy. The first two resulted in water damage to the electronics, but the third managed to work. It kept the water out, but also prevents reprogramming of the controller.

Although not successful, we would have loved to see the process of dipping the fish in a churning vat of molten glue. Once perfected, this may be the perfect platform for carrying our weapons of doom.