And So Castings Made of (Kinetic) Sand . . . Turn Out Pretty Well, Actually

That kinetic sand stuff is pretty cool. It’s soft, it builds motor skills, and outside of sprinkling it on carpet, it’s not messy. If you don’t know, it’s 98% sand and 2% polydimethylsiloxane, which is a major component of Silly Putty, and according to a certain yellow and red clown, it’s safe enough to put in chicken nuggets. [Chris]’s wife bought him some, probably because she wanted to see him play around with something that isn’t potentially deadly for a change. In the course of researching its magical properties, he found out that it doesn’t really have a thermal breakdown point, per se. At high enough temperatures, It vitrifies like a sand castle in a mushroom cloud. Between this property and its malleability, [Chris] thought he’d have a reasonable substitute for founding sand. As you can see in his latest experiment, he was right. As a bonus, he managed to turn the benign into the dangerous.

[Chris] had never cast aluminium before, so he decided to start small by making an offset cam for a rotary broach. He packed some magic sand in a wax paper cup and shoved the cam in to make the negative. Then he cut down some aluminium rod and put it in a graphite crucible. He stuck his DC arc welder’s electrode down into the crucible and cranked it up to 50A. That wasn’t enough, so he went to 110. The crucible was soon glowing orange. He carefully poured the molten aluminium into the mold. Make the jump to see how it panned out.

Spoiler alert: there’s no cussin’ this time!

Continue reading “And So Castings Made of (Kinetic) Sand . . . Turn Out Pretty Well, Actually”

DIY Coffee Maker Filters Out Manufacturer Specificity

Coffeemaker made from 3D-printed parts and scrap aluminium

This DIY electric coffeemaker prototype uses an assemblage of 3D-printed parts and cast aluminium. [siemenc]’s main goal with this project was to utilize and demonstrate recycling and re-usability. He used Filabot filament exclusively and melted down scrap aluminium such as cans, foil, and CNC mill waste in an oven he fashioned from an old fire extinguisher. He also cast the aluminium parts himself from 3D-printed positives.

Of course, he had to buy the things that make this a coffeemaker such as the hoses, the fuse, and the heating element. If you’re wondering why he didn’t salvage these parts from yard sale machinery, it’s because he wanted to be able to replace any part of it and have it last as long as he needs it to last. The innards he used are not specific to any model, so he should be able to easily find a replacement.

Just like a pour over set up, [siemenc] has fine control over the strength and quantity of the brew. We particularly like this machine’s exotic bird looks as well; it may be a prototype, but it’s quite stylish. If you’re looking to go all the way with DIY coffee, why not grow your own beans and then roast the beans yourself?

 

Update: lost PLA metal casting — The Movie

lost-pla-metal-casting-movie

Turning 3D printed plastic parts into metal objects is not a new concept. But we don’t see a lot of it and enjoyed watching the documentary version of [3DTOPO’s] lost PLA metal casting process so much we figured you’d want to see it too.

The thirty-five minute video walks through every part of the process which we originally learned about in September of last year. The process was developed as a way to fabricate parts that will be used in high-stress applications. For instance, the part seen above is a mounting bracket for the ball screws that moves the Z axis on a huge CNC build he’s been working on. A plastic part will break under the strain so he needed to make it out of aluminum alloy.

To start, the piece is modeled and printed in plastic to check the fit. Once it’s just right he scales it to 103% and prints it again to account for the shrinking of the metal as it cools. The next step is pictured above, adding paths using rigid foam insulation that allow for the metal pour and for air to escape. This is packed into a plaster and sand mold which dries before being cooked in a furnace to vaporize the foam and PLA. This leaves a perfect mold for the metal pour.

After the break you can see a 5-minute overview version of the project.

Continue reading “Update: lost PLA metal casting — The Movie”

Cutting styrofoam with a CNC machine and turning it into aluminum

One of the most popular ways of turning an object trapped inside the world of a computer into a real, metal object is the art of lost wax, or lost foam casting. In this process, a full-scale model of the object to be made in metal is crafted in either foam or wax, placed in a pile of sand, and burned away by molten metal.

[ptflea] over at the Bamberg, Germany hackerspace Backspace came up with a very clever build that automatically cuts foam into the desired shape, ready to be taken out to the backyard foundry. The build is based around an old flatbed scanner and a hot wire cutter. The old scanner conveniently had  an equal number of steps per axis, so attaching an Adafruit motor shield and replacing the old control electronics was just an issue of finding the correct resistors.

Software control is provided by a Processing app [ptflea] whipped up and is able to carefully cut very delicate shapes that even the steadiest hand would have trouble with.

Making stuff out of styrofoam is cool and all, but the real goal for this project was setting things on fire and melting old heatsinks. The styrofoam molds were placed in a bucket full of sand, and the furnace – a few ytong bricks, a crucible, and a propane burner – started to melt some aluminum. The molten aluminum was poured onto the mold and after cooling, the makers of Backspace had a few very cool aluminum trinkets.

A nice build that is able to produce some very nice metal objects. We suspect, though, that a higher-density foam (something along the lines of blue or green insulation sheets, if they have those in Germany) could produce an even higher level of detail if you’d like to build your own.

Videos after the break.

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Melting beer cans and building engines

What do you do if you’ve got a fully equipped machine shop and you’re tired of taking old beer cans to the recycler? If you’re like [Brock], you’ll probably end up melting those cans down to build an engine.

After gathering 50 pounds of beer cans and melting them down into ingots of various sizes, [Brock] and company had a lot of aluminum and nothing to build. Eventually, someone got the idea to build an internal combustion engine out of these beer can ingots.

So far, the beer can engine crew has built two engines from these beer can ingots. The four-stroke engine started off as a 5-inch aluminum cube, bored and milled into something resembling an engine block. When [Brock] and the beer can engine team completed their four-stroke masterpiece, they had a water-cooled engine displacing 150cc with a single 2″ bore piston. The two-stroke engine is a much simpler affair with a 1 inch bore displacing 19cc.

Even though there’s no information at all covering the pottery kiln foundry used to melt the beer cans into ingots, it’s an amazing piece of work building and engine from the ground up.

You can check out a few videos of both engines after the break.

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Building a foundry in your backyard

[th3BadWolf] has been wanting to build a foundry for some time now. Done right, it’s a very neat tool; it’s fairly easy to do aluminum castings, and if you’re clever enough a foundry can lead to building large machine tools such as a lathe or a mill. Anything worth doing is worth overdoing, so [BadWolf] is designing his foundry to melt 150 pounds of aluminum every 45 minutes.

The build began with a humble oil barrel. [th3BadWolf] cut the top off of the barrel and began lining the inside of the barrel with a ceramic blanket and refractory bricks. To hold this somewhat precarious assemblage of blanket and brick together, [BadWolf] is holding everything together with 3000° F cement.

The body of the furnace is nearly complete, but [BadWolf] still has to drill a few holes for the burner system. He’s going to start each burn with Propane, then move over to engine oil when the furnace gets hot enough. Truly an awesome project, and we can’t wait to see the results.