Pewter Casting with PLA

Over on, [bms.had] is showing his technique for 3D printing molds that he uses to cast (lead-free) pewter objects. The process looks simple enough, and if you have a 3D printer, you only need some lead-free pewter, a cheap toaster oven, and PLA filament. He’s made two videos (below) that do an excellent job of showing the steps required.

Even though the pewter is hot enough to melt the PLA, it doesn’t appear to be a major problem if you quench the piece fast enough. According to [bms.had], a slower quench will melt some PLA although that creates a smoother surface. You can see the 0.31 mm layer lines in the cast, though, although you can use any layer height you like to control that. Creating the mold is simple (the videos use Tinkercad, although anything suitable for creating 3D models would work). You essentially attach a funnel to your part and make the entire part a hole inside an enveloping shape.

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Casting Engagement Rings (Or Other Small Metal Parts!)

[Paul Williams] wrote in to tell us about his most recent and dangerous endeavor. Marriage.

As a masters student in Mechanical Engineering, he wanted to give his wife (to be) to be a completely unique engagement ring — but as you can imagine, custom engagement rings aren’t cheap. So he decided to learn how to make it himself.

During the learning process he kept good notes and has produced a most excellent Instructable explaining the entire process — How to make the tools you’ll need, using different techniques and common problems you might have. He even describes in detail how to make your own mini-kiln (complete with PID control), a vacuum chamber, a wax injector and even the process of centrifugal casting. Continue reading “Casting Engagement Rings (Or Other Small Metal Parts!)”

Making keys after the apocalypse

Making keys is an amazing art with a lot of skill and technique involved. For those of you living in a post-apocalyptic world, [Dan] has a much simpler solution to the problems of having one too few keys for your locks and deadbolts – just cast them out of scrap with the power of the sun.

To make the mold of the key, [Dan] is using a two-piece plaster of paris mold. First, a thick layer of plaster is laid down in a small container and the key floated on the surface. After drying, sprues are put in with clay and the key embedded in a curing plaster block. After a few hours, a proper mold is created ready to receive molten metal.

The casting material is zinc – not as hard as the original steel key, but more than strong enough to turn a lock. This zinc is melted in a steel and plaster crucible with a gigantic fresnel lens.

As for the utility of this method of copying keys after the apocalypse, we’ll have to wonder how practical this method is. A giant fresnel lens isn’t just something you randomly find unless you’re going house to house looking for projection TVs, and finding a can of mold release after the end of the world is beyond credulity. That said, it’s a cool demonstration of metal casting that can be easily accomplished at home or at any hackerspace.

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