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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From Scrap To Sword: Casting Pewter

[TheBackyardScientist] has been living up to his name, this time by casting a pewter sword in his yard. Pewter is a soft alloy of mostly (85–99%) tin along with copper, antimony and bismuth. Older pewter castings often used lead as well. The great thing about pewter is its low melting point of 170–230 °C. At such low temperatures, pewter can be melted down on a common hot plate. Think of it as an easy way to get into the world of metal casting – no forge required. Of course, anyone who has been splashed with solder will tell you that hot molten metal always deserves a lot of respect.

[BackyardScientist] obtained his metal by hunting the local thrift stores. He used the “lost foam” method of casting, by carving a sword out of styrofoam. The sword was embedded in a 5 gallon bucket of sand with a riser to allow the mold to be filled. The pewter was melted on a cheap hot plate, and poured into the mold. The hot metal melts the foam on contact, simultaneously filling up the cavity left over in the sand mold. [BackyardScientist] was left with a solid pewter sword. It won’t hold an edge, but it is a great illustration of the technique.

Click past the break to see [TheBackyardScientist’s] video.

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Hackaday Links: April 18, 2012

Sandcasting at the beach

[mkb] sent in a video he found of [Max Lamb] sandcasting a stool at a beach in England. The material is pewter, or >90% tin with a little bit copper and antimony thrown in for good measure. While we’re sure there will be a few complaints from environmentalists, it’s still a cool video to see.

Your project needs an OLED display

Here’s a Kickstarter for a tiny 96×16 OLED display. Connect this thing to any I2C bus and you get a 15×2 character display (or a graphic display if that’s your inclination) very easily. Thanks to [Chris] for sending this one in.

Here’s one for a larf

[Ryan Inman] is suing 20 companies because he got mercury poisoning from vacuum tubes. Read that last line again. Most of the companies that sell antique/repro/hard-to-find components like Angela Instruments, Antique Electronic Supply, and even eBay are listed as defendants in the case. This might put at least one company out of business even though they never sold [Ryan] a vacuum tube edit: they did sell him a neon bulb, and courts are generally idiotic when it comes to technological issues. It’s hilarious and sad, so we’ll keep you updated if we get more info.

Nostalgia, the pain from an old wound

The Adafruit blog posted an excellent piece on the Apple ][ game Rocky’s Boots, an educational game from 1982 that teaches kids how to connect logic gates. You can play this game in your browser, but we’d like to hear our stories of ancient video games that teach you engineering concepts like The Incredible Machine or Widget Workshop. Leave a note in the comments if we’re leaving any out.

A question posed to the community

A company is giving away credit card readers that plug into the headphone jack of an iDevice. [J Smith] writes in to ask us if anyone has gotten one of these and opened them up. Like [J Smith] we’re expecting something a repeat of the CueCat where free hardware is opened up to everybody. If you’ve done a teardown of one of these card readers, send it in.

3DS homebrew

[Mike] sent us a link to [neimod]’s Flickr photostream. It looks like we’re on the cusp of tearing open the Nintendo 3DS for homebrew apps. Someone who uses this much hot glue must know what they’re doing, right?