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Alloy casting a CNC-milled foam pattern

Alloy casting a CNC-milled foam pattern


MAKE subscriber FrankG is working on an electric conversion of a Suzuki motorbike, and needed a custom part. He CNC-milled some foam and then cast the part using a sand mold. The documentation page is full of makery goodness ranging from CAD drawings to molten metal. The video is very maker-zen.

22 thoughts on “Alloy casting a CNC-milled foam pattern

  1. Bob Sinclair says:

    This video makes it all seem so easy. I’m sure anyone could do this after just a few attempts, if they’d pay close attention to this.

    This site needs more of this sort of projects, and less “i can blink an LED” articles.

  2. Bob D. says:

    I completely agree with you, brother. This video was really good and showed almost every step between design and use of a part. Now I know a simple way to do sand casting which is really cool. I figured they always used some kind of low melt point metal or wax substance that was heated and poured out before dumping in the aluminum. No! How easy this now is using foam!

    I also agree that this site equates art with gluing down LED lights. Art is, of course, subjective so I can’t argue what is or is not art. It’s just that I’m more the kind of guy that wants to see much more interesting articles, hell, even if they’re about those weirdo steampunks ;) , so long as the project is more involved than hooking up some lights.

    Really cool video guys!

  3. Rich says:

    That was absolutely amazing. It looks like if you’re not lucky enough to have a CNC mill, you could probably just lathe up some pulleys (sans fancy lettering, natch) out of the foam.

    I’m working on an EV bike project and might need something like this… I love the use of an old oil furnace burner!

    Stellar video – it reminds me that people have been doing this sort of thing in the garages long before we could buy them off the shelf. Bravo!

  4. selfSilent says:

    It seemed to work really well, I was surprised it cast so well using only a single sprue.
    I was convinced the air from the foam would become trapped creating a poor finish.

  5. Fredex says:

    I love Olde School makery.

  6. FrankG says:

    Hey All!

    Thanks for the positive feedback!!!

    I’m glad that the video is so well recieved… it was an absolute blast working on this project and sharing it via the web-site and Video on the web…

    At some point in the future I hope to put together a series of short tutorials that cover the basics of metal casting in more detail…

    It was a real challenge to shoe-horn as much into the 10 Min clip as shown and keep it within the context of the Suzuk-E project.

  7. Mitch Molton says:

    As a representative for Molton Metals, I would like to point out that my company, Molton Metals, was not involved with this project, regardless of what the last line in the article states.

    Molton Metals is proud of our products and reacts strongly to being associated with backyard foam-loss casting by stinky hippies.

    Thank you.

  8. Alloy casting a CNC-milled foam pattern Becky Stern says:

    Hi Mitch, sorry for the spelling error, it’s fixed now. Clearly I meant “molten.” Sorry for any confusion, even if you did call us “stinky.” =]

  9. rob0 says:

    This was the best post for a while. Truly inspiring – and the video was really well put together.

    Great job.

    Make please do more of this – less “I stacked all my used beer cans in a pyramid”.

  10. FrankG says:


    What Mitch said… Moulten Metals had absolutely, positively, nothing to do with this project…

    Though it would be nice to have an extra set of hands around to get some chores done…

    Stinky Hippies, indeed!

  11. JennaSys says:

    That was one very well put together video! Thank you for taking the time to do that and share it with the rest of us aspiring makers. The way you presented the manufacturing process from start to finish was very informative if not downright inspiring, and I’m definitely looking forward to your metal casting how-to. Loved the homemade background music too, very cool!

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Becky Stern is a Content Creator at Autodesk/Instructables, and part time faculty at New York’s School of Visual Arts Products of Design grad program. Making and sharing are her two biggest passions, and she's created hundreds of free online DIY tutorials and videos, mostly about technology and its intersection with crafts. Find her @bekathwia on YouTube/Twitter/Instagram.

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