Iron Man 2: Sammy The Silly (Putty) Seal

Posted by on August 5, 2011

If you’re following along in our Iron Man series, you know that we still have most of the 5 pound bag of iron oxide powder (Fe3O4, or magnetite) we purchased off of Amazon.  It turns out that 5 pounds of iron oxide powder goes a long way. And it turns out that iron oxide powder mixes into Silly Putty very easily.

Read to the end for an “Attractive” giveaway. Oh, the Iron-y.


  • Iron Oxide Powder (several tablespoons)
  • Silly Putty
  • Magnet



1. Protect your work surface (old newspaper works great)



2. Incorporate iron oxide powder into the silly putty. Knead it like bread dough, squish it, stretch it, whatever it takes.




The final product should look very black and glossy.


The Putty now has enough iron in it (Magnetite has a high percentage of iron  relative to oxygen – 3 iron atoms for every 4 oxygen atoms) to be attracted to a magnet.


And here’s a video we made after shaping the Silly Putty into Sammy, the Silly Putty Seal. Sammy was supposed to be a dog but all of our attempts at creating a dog ended in Seal.


We will probably add more iron oxide powder after this, and see if that makes things even more interesting.

If you try this, please take pictures or videos and post the link here! We’d love to see what you come up with.


Here the link to our previous project:  Iron Man 1: Reading a Magnetic Strip



Rare Earth Magnets work great for this, and we got ours out of an old computer hard drive.  If you acquire one,  be particularly careful around children.  Here’s a warning from one site: “Can damage computer gear & credit cards. Handle with care. 2 magnets can snap together with enough force to break a finger or shatter on impact.” If a child SWALLOWS one (or two) this can be VERY bad.  Let’s say like Emergency Surgery bad.

The bag of powdered iron oxide did tell us to consult the MSDS.  For those of you who have your own source of powdered iron (there are several good options) and decide that you will brave the hazards (this is sarcasm) of powdered iron, the gist of it is to not inhale huge plumes of the stuff.


Credit where credit is due:  We got this idea from Instructables.


GIVEAWAY!   Want to make your Putty attractive to fine magnets everywhere? The first 5 commenters (Continental US only) on the Iron Man posts will get 2 TBSP of my Magnetite Powder. Because I still have nearly 5 pounds of the stuff. Just indicate that you are interested in receiving it, and I’ll contact you via email.

3 Responses to Iron Man 2: Sammy The Silly (Putty) Seal

  1. Bernardo Pybus

    this project is georgeous ! if you don’t mind i’ll share it on my blog and i’ll try to to this at home for our advent calendar. Thanks a lots for the templates !

  2. Francisco

    A simple and inlitlegent point, well made. Thanks!

  3. Rachel

    Does the offer still stand? lol. 🙂 I know this is an old post, but what fun. 🙂

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