Crackle paint is useful for giving objects a weathered, old appearance as well as adding an interesting texture to new items. Speciality paints like crackle paint are often more expensive than standard paints, and usually come in a limited number of colours. To save money and get the exact colour that you want, you can mix up your own crackle paint at home using basic ingredients.
Whisk the flour into the water until the two ingredients are thoroughly mixed together, free of any lumps.
Cook the flour mixture into a wheat paste over medium heat on the stove, whisking frequently. The paste is finished when the mixture thickens, gaining the consistency of gravy. Remove from the stove and let cool.
Add the cornstarch to the wheat paste. Stir with a fork until the mixture is smooth.
Colour the mixture with food colouring. Make an old-fashioned, pale colour using a mixture of primary food colouring.
Thin the mixture with water as needed, until it is the consistency of thin yoghurt or of house paint.
Apply the mixture as paint to surfaces you want to coat with cracked paint. Use a house paint brush to apply the mixture just as you would apply paint.
Let the mixture air dry for several hours. Precise drying times will depend on heat and humidity conditions, but if you want to speed it up, use a hair dryer or house fans. When the mixture drys, it will crack.
Spray the mixture with matt varnish. This will give it a slight sheen, making it look realistic, while keeping the mixture from being powdery to the touch (though it will still be flaky).