casting

110 Articles

Casting Metal Directly Into 3D Printed Molds

August 27, 2017 by 24 Comments

Casting metal and 3D printing go together like nuts and gum, and there are no shortage techniques that use the two together. Lost PLA casting is common, and sculptors are getting turned on to creating their works in plastic first before sending it off to the foundry. Now the folks at FormLabs have turned the whole ‘casting metal and 3D printer’ thing on its head: they’re printing sacrificial molds to cast pewter.

There are two techniques demonstrated in this tutorial, but the real winner here is printing a complete sacrificial mold for pewter miniatures. While this technique requires a little bit of work including washing, curing, and a bit of post-processing, you would have to do that anyway with anything coming out of a resin printer.

The material of choice for these molds is a high temp resin with a heat deflection temperature of 289 °C. Using a pewter alloy that melts at 260 °C, casting a metal miniature is as simple as pouring molten metal into a mold. Demolding might be a little finicky, but with a small screwdriver used as a chisel, it’s possible to get the cast newly parts out.

We’ve seen pewter casting with PLA, but the quality available from the Form resin printers is truly amazing and produces some great looking miniatures.

Harvesting Copper From Microwave Ovens

August 26, 2017 by 51 Comments

Obsolete appliances were once a gold mine of parts, free for the taking with a few snips of your diagonal cutters. Times have changed, though, and most devices yield only a paltry supply of parts, so much so that only by harvesting raw materials can you get much value out of them. And so we have this example of reclaiming copper from used microwave ovens.

The primary source of copper in most microwaves is the transformer, which we usually see re-tasked for everything from spot welders to material handling electromagnets. But the transformer is not the only source of the red metal; [eWaste Ben] also harvests it from relay coils and the main coil and shading coils of the fan motor.  The bounty is melted down in an electric foundry and cast in a graphite mold into a lovely ingot.

Unless you’re into repeatedly casting copper trinkets, a large bar of reclaimed copper might not be something you have a burning need to possess. But bearing in mind that copper can go for about $2.50 a pound at the scrap yard, there’s some money to be made, especially with dead microwaves essentially free for the taking. As [Ben] points out, taking the extra step to melt and cast the copper harvested from microwaves makes no sense if all you’re going to do is sell the scrap, but it’s nice to know how to do it just the same.

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A Great Way To Make Quick And Easy Knobs

August 16, 2017 by 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 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 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 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 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.