I saw that it was possible to buy reactive paints from a few companies, most in the US. But I'm in Ireland...$$$
So I decided to do a bit of research and make my own. It involves a reactive paint and a rusting solution.
For the paint you need:
- Acrylic matt medium
- Iron filler powder
- 100mls water
- 10g Copper Sulphate
- 10g Ammonium Chloride
Apply a layer all over your object to be rusty. Allow to dry completely (cure), ideally over night.
Apply a second layer of iron paint but before it dries, spritz lightly with the rusting solution.(you don't want to wash the paint off)
Leave it to dry.
Within a few hours you should see a rusty effect starting to appear. It will keep reacting for days and become more rusty.
I like to spray another mist over the top and heat it with a hair drier or heat gun to accelerate the reaction. I did this 3 times over a day.
Next day the result was much like the image above. It has reacted a little more in the past few weeks but not a massive change.
If you use this I'd love to see the results. My email is on the contact page of my website.