Sand Cast Banana For Scale Is So Metal

If you’ve been on Reddit over the past year, you’ve likely encountered the “banana for scale” meme. [BFG121] felt that the size variation of bananas would not do – there needed to be a standard. He decided to make a metal banana out of re-purposed aluminum. He created his own furnace out of everyday objects including a hair dryer, metal bucket, cement, fire clay, and sand. [BFG121] used a typical banana as the reference for his sand casting mold. After melting the aluminum in his homemade furnace, he poured it into the empty mold, making sure there was an extra hole for the displaced air to escape. The end result is a perfect replica of a banana. [BFG121] made two aluminum bananas, and stamped each one with a serial number. One was given to Imgur headquarters while the other was auctioned on eBay. The winning bid (#39) was $67 USD, a very good ROI.

If you want to learn more about metal casting, check out myfordboy’s channel on YouTube.  You can also see an example of the “banana for scale” in this Hackaday article about a giant spirograph. Our only suggestion to [BFG121] is to send some to ASTM, NIST, and BIPM!

[via Reddit]

23 thoughts on “Sand Cast Banana For Scale Is So Metal

  1. Isn’t his “standard” banana now 3 percent smaller than the real thing? 3 percent was the number I heard to allow for the shrinkage of Al as it cools. Been a while since I’ve seen charcoal used. Seems like everyone uses propane these days.

    Nice banana though!

      1. The problem with that aluminium standard banana is that it is only good for scale. A real standard banana (with about 422 mg of potassium, a tiny amount of which is potassium-40) can also be used for checking geiger counters are working. :)

        1. Well, then you’d need to burn a banana, somehow seperate the K from the rest of the ash, and mill a hole in the banana. It’s metal, so you’re not going to get the beta particles from every direction, but having a plastic window would be great.

          Banana for scale check source. Somebody kickstart it.

      1. I don’t know that I *dislike* the layout itself, per se– it has a rather sharp and clean look, though the all-caps titles are dumb, as the post about pissing in the wind proved –but I keep forgetting to click ‘blog’ immediately on the frontpage, and spend a minute looking for the ‘older posts’ link to no avail when I reach the end of the ‘from the blog’ section. Gonna take a while getting used to that. :(

  2. I love this. Sand casting is very cool, but can you scan this for 3D printing? Much easier to distribute an STL file. And you will have shared THE standard banana for scale with the ROTW.

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