Anodize

I bought some butterfly paperclips, like the one I use as a logo. I tried to anodize one using a blowtorch: a Bernzomatic TS8000 that I bought to sear sous vide steaks.

I was hoping to turn the paperclip a bluish color to match the logo. The paperclips are steel, and as you heat them, they change color permanently from silver to gold to purple to gray. This is because a layer of iron oxide is forming on the surface which creates wave phasing effects: the perceived wavelength of the light changes resulting in different colors, because some light reflects off the surface and some penetrates the oxide layer and reflects off the original surface.

This video from The Action Lab also explains it.

I thought that since the metal is so thin, it would be easy to evenly heat the whole piece to get a consistent color. It’s not so easy. The electrode method is much better I’m sure, but I was just playing around.