Fire Extinguisher Ball Mill Destined to Grind Kitty Litter

Nothing says hack like a tool quickly assembled from a few scrap-heap parts. For [Turbo Conquering Mega Eagle], his junkyard finds were a fire extinguisher, an old office fan, and a few scraps of plywood; the result was a quick and easy ball mill.

There’s very little mention of what said ball mill will be for — [TCME] said something about milling bentonite clay, AKA kitty litter — but that’s hardly the point. Having previously fabricated a much smaller version of this ball mill that could chuck up in his lathe, he scaled this one up considerably. The spent fire extinguisher was relieved of the valve and some external bits to create the mill’s drum. Plywood was used for a quick frame to support rollers and to turn a couple of pulleys for the running gear. The fan motor proved barely capable of performing, though, even with the mechanical advantage of the pulleys and an improvised drive belt. The motor just didn’t have the oomph to turn the drum when loaded with ceramic balls, but a quick adjustment to the drive train did the trick. The video below shows the whole build process, which couldn’t have taken much more than a couple of hours.

It looks like a sand casting project may be on deck for [TCME]’s milled bentonite, so we’ll look forward to that. Perhaps his other recent fire extinguisher build will make an appearance in that video too.

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Custom Aluminum Wheels Teach a Thing or Two about Casting

For some mobile projects like small carts or rolling cabinets, your standard casters from Harbor Freight will do just fine. But some projects need big, beefy wheels, and these custom cast aluminum wheels certainly make a statement. Mostly, “Watch your toes!”

To be honest, [Brian Oltrogge]’s wheels are an accessory in search of a project, and won’t be crushing feet anytime soon. He made them just to make them, but we have no beef with that. They’ve got a great look that hearkens back to a time when heavy metal meant something else entirely, and things were made to last. Of course, being cast from aluminum sort of works against that, but there are practical limits to what can be done in the home foundry. [Brian] started with a session of CAD witchcraft followed by machining the cores for his molds. Rather than doing this as lost foam or PLA, he milled the cores from poplar wood. His sand mix is a cut above what we usually see in home-brew sand casting — sodium silicate sand that can be cured with carbon dioxide. All his careful preparation meant the pour went off without a hitch, and the wheels look great.

We’ve featured quite a few metal casting projects recently, some that went well and some that didn’t. [Brian] looks like he knows what he’s doing, and we appreciate the workmanship that he puts on display here.

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Fail of the Week: Sand Casting Copper

There’s trouble in the Kingdom of Random – the smithies of the realm are having trouble sand-casting copper. And while [King Grant] might not be directly asking for help, we think the Hackaday community might have plenty to say about his efforts.

We’ve all seen plenty of sand casting efforts before, including attempts to make otherwise unobtainable engine parts. And “lost foam” casting, where a model of the part is constructed of polystyrene foam that flashes off when the molten metal is poured, is a relatively new twist on the technique that’s been used to good effect on a recent Gingery lathe build. But most backyard foundries work in aluminum, which is apparently much easier to work with than the copper that [Grant Thompson] is working with. Ironically, his first pour worked the best — not perfect, but at least the islands defining the spokes of his decorative piece didn’t break off and float away as they did in every pour shown in the video below. That leads us to think that the greensand is too dry by the second video. Or perhaps the density of copper just makes it more likely for the sand to float. Maybe a cope and drag mold is in order to keep the islands in place and direct the flow of the copper better.

We know there’s a lot of expertise out there, so sound off in the comments about what you think is going on with these pours.

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Custom Engine Parts from a Backyard Foundry

Building a car engine can be a labor of love. Making everything perfect in terms of both performance and appearance is part engineering and part artistry. Setting your creation apart from the crowd is important, and what better way to make it your own than by casting your own parts from old beer cans?

[kingkongslie] has been collecting parts for a dune buggy build, apparently using the classic VW Beetle platform as a starting point. The air-cooled engine of a Bug likes to breathe, so [kingkongslie] decided to sand-cast a custom crankcase breather from aluminum.

Casting solid parts is a neat trick but hardly new; we’ve covered the techniques for casting plastic, pewter, and even soap. The complexity of this project comes from the fact that the part needs to be hollow. [kingkongslie] managed this with a core made of play sand and sodium silicate from radiator stop-leak solution hardened with a shot of carbon dioxide. Sure, it looks like a Rice Krispie treat, but a core like that will stand up to the molten aluminum while becoming weak enough to easily remove later. The whole complex mold was assembled, beer cans melted in an impromptu charcoal and hair-dryer foundry, and after one false start, a shiny new custom part emerged from the sand.

We’ve got to hand it to [kingkongslie] – this was a nice piece of work that resulted in a great looking part. But what we love about this is not only all the cool casting techniques that were demonstrated but also the minimalist approach to everything. We can all do stuff like this, and we probably should.

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