A Great Way To Make Quick And Easy Knobs

August 16, 2017 by Donald Papp 34 Comments

Here’s a great way to quickly and easily make attractive and functional knobs with no tools required. All you need is some casting resin (epoxy would do in a pinch), a silicone mold intended for candy, and some socket head bolts. With the right preparation and a bit of careful placement and attention, smooth and functional knob ends are only minutes away. Embedded below is a short video demonstrating the process.

These may not replace purpose-made knobs for final products, but for prototypes or to use around the shop on jigs, clamps, or furniture they certainly fit the bill. With a layer of adhesive fabric or rubber, they might even make serviceable adjustable feet for low-stress loads.

This technique could be extended to reproducing broken or missing dakaware or bakelite knobs. This, of course, would require an original, unbroken knob and a small silicone mold, but it’s still a project that’s well within the capabilities of the garage-bound hacker.

While we’re on the subject of knobs, don’t forget we’ve seen an excellent method of repairing knobs as well.

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Silicone Molds For Stove-Top Metal Casting

August 9, 2017 by Dan Maloney 25 Comments

Casting metal parts from 3D-printed plastic or Styrofoam models is all the rage these days, and for good reason — casting is a way to turn one-offs into mass-produced parts. Seems like most of the metal casting projects we feature are aluminum in sand molds, though, so it’s refreshing to see a casting project using silicone molds to cast low-melting point metals.

Don’t get us wrong — sand-cast aluminum is a great method that can even be used to build a lathe from scratch. But not everyone wants to build a foundry and learn the sometimes fussy craft of creating sand molds. [Chris Deprisco] wanted to explore low-melting point bismuth alloys and set about making silicone rubber molds of a 3D-printed Maltese falcon. The bismuth-tin alloy, sold as a substitute for casting lead fishing weights, melts on at 281°F (138°C) and is cool enough for the mold to handle. Initial problems with bubbles in the cast led to a pressure vessel fix, and a dull, grainy surface was fixed by warming the mold before the pour. And unlike sand molds, silicone molds are reusable.

Of course if aluminum is still your material of choice, there’s no need for a complicated foundry. A tuna can, a loaf of bread, and a handful of play sand is all you need to make custom parts.

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The Tuna Fish Sandwich Foundry

July 21, 2017 by Dan Maloney 37 Comments

Can you build a foundry out of a loaf of bread and a can of tuna fish? As it turns out, yes you can. And not only can you melt aluminum in said foundry but you can also make a mold from plain beach sand and cast a usable part.

Through the magic of backwoods engineering and that can-do Canadian attitude, [AvE] demonstrates in his inimitable style how a pyrolized loaf of sourdough bread can serve as a perfectly acceptable foundry, using a tuna can as a crucible. We covered [AvE]’s carbon foam creation process before and showed some of its amazing properties, including the refractory characteristics requisite for foundry service. Once reduced to carbon foam, the bread can easily handle the flame of a propane torch and contain the heat long enough to melt aluminum. And using nothing more than beach sand, [AvE] was able to lost-foam cast a knob-like part. Pretty impressive results for such a low-end, field expedient setup.

Normally we warn our more tender-eared readers about [AvE]’s colorful language, lest they succumb to the vapors when he lets the salt out. But he showed remarkable restraint with this one, even with his cutting mat aflame. Pretty SFW, so enjoy seeing what you can do with nothing.

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Custom Aluminum Wheels Teach A Thing Or Two About Casting

July 1, 2017 by Dan Maloney 35 Comments

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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Gateway To Metal Casting

June 30, 2017 by Michael Uttmark 15 Comments

Casting is an exciting and very useful pastime, but it’s not exactly common these days. That’s a problem whether you’re just getting started or have been doing it for years: everyone can use the advice of another. Fear not! The US Department of Energy is here to help with the Industrial Metal’s Program’s Metal Casting cornucopia.

Although not strictly a hack, this is certainly a facilitator of hacks and any experienced user would do themselves some good by perusing the site. Click on the maps to find complex issues presented remarkably well for papers at this level of rigor. Seriously, check them out.

However, since these papers go into such depth, we can’t really say the material is beginner friendly. That’s not to say it would be bad for a newbie to read through, just that it might be a bit discouraging. But, if you need to figure out where to start in the maze of molds and sand and molten metal, we might have some articles that might help you out.

Do y’all know of any good casting resources on the interwebs? If so, leave ’em in the comments!

Thanks [RunnerPack] for sending this in.

Celebrating A Subscriber Milestone With A Copper YouTube Play Button

June 14, 2017 by Dan Maloney 7 Comments

YouTube channels unboxing their latest “Play Button Award,” a replica of the famous logo in silver, gold, or faux-diamond depending on the popularity of the channel, are getting passé. But a metalworking channel that makes its own copper Play Button award to celebrate 25,000 subs is something worth watching.

[Chris DePrisco] is a bit of a jack-of-all-trades, working in various materials but with a strong focus on metalwork. He recently completed a beefy home-brew vertical milling center; we covered his attempt to leverage that platform by adding an extruder and turning it into a large bed 3D printer. For the Play Button build, [Chris] turned to the VMC to mill a mold from what appears to be a block of graphite; good luck cleaning that mess up. He melted copper scrap in a homemade electric furnace and poured it into the preheated mold — a solid tip for [The King of Random]’s next copper casting attempt. The rough blank was CNC machined and polished into the Play Button, and finally mounted behind glass neatly inked with paint pens in the versatile VMC. The final result is far nicer than any of the other Button awards, at least in our opinion.

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Lost PLA Casting Brings Out The Beauty Of Macromolecules

January 2, 2017 by Dan Maloney 6 Comments

Biochemistry texts are loaded with images of the proteins, nucleic acids, and other biopolymers that make up life. Depictions of the 3D structure of macromolecules based on crystallography and models of their most favorable thermodynamic conformations are important tools. And some are just plain beautiful, which is why artist [Mike Tyka] has taken to using lost-PLA casting to create sculptures of macromolecules from bronze, copper, and glass.

We normally don’t cover strictly artistic projects here at Hackaday, although we do make exceptions, such as when the art makes a commentary on technology’s place in society. In [Mike]’s case, not only is his art beautiful and dripping with nerd street cred, but his techniques can be translated to other less artsy projects.

For “Tears”, his sculpture of the enzyme lysozyme shown in the banner image, [Mike] started with crystallographic data that pinpoints every peptide residue in the protein. A model is created for the 3D printer, with careful attention paid to how the finished print can be split apart to allow casting. Clear PLA filament is used for the positive because it burns out of the mold better than colored plastic. The prints are solvent smoothed, sprues and air vents added, and the positive is coated with a plaster mix appropriate for the sculpture medium before the plastic is melted out and the mold is ready for casting.

[Mike]’s sculpture page is well worth a look even if you have no interest in macromolecules or casting techniques. And if you ever think you’ll want to start lost-PLA casting, be sure to look over his build logs for plenty of tips and tricks. “Tears” is executed in bronze and glass, and [Mike]’s description is full of advice on how to handle casting such vastly different media.

Thanks to [Dave Z.] for the tip.