A while ago, out of curiosity, I picked up some Derivan Matisse dry medium ferrous powder. Apparently it can be used to create magnetic coatings when mixed with varnish, but I was far more interested in its rusting abilities.
I could have just mixed it up and painted it on some card to test it out, but I like to created finished pieces where I can. I grabbed a little wooden box (about 6cm square and 3.5cm tall) from my stash along with a few scraps from my “save absolutely everything box“, including a small heat sink that was on something my other half threw out — you can find some interesting bits in other people’s trash. I glued the bits to the box and let it all dry.
Then came the interesting part.
I mixed the ferrous powder into a few different colours of acrylic paint — no exact proportions, just making sure that it wasn’t too thick to paint with — and then covered the outside of the box and left it to dry completely.
Of course, unless you are really patient and want to let nature take its course over many months, you need something to speed up the rusting process. I’d found an old video demonstrating the process, and in that they used a mixture of 85mls hydrogen peroxide 3%, 15mls white vinegar and 1 level teaspoon salt in a spray bottle.
Once the paint was dry I just sprayed it liberally with the activating solution and watched as it reacted with the ferrous powder in the paint. When it was finished an everything had dried again, it left this wonderfully rusty finish with hints of the colour coming through.
I couldn’t leave it like that though, I had to decorate the inside as well. The purple paint is quite translucent so I gave the wood a coat of white gesso first. I found a silver cog in my stash that contrasts nicely with the purple, made a tiny stuffed cushion for the base and glued some beads in the corners (and one on the cog) to finish it off.