What is the hairspray chipping technique?

The hairspray chipping technique has been around for decades, but recently it seems to have been rediscovered and is being talked about on many forums. And with good reason too because the effects achievable using the technique are truly outstanding. But what is it?

The aim is to realistically replicate the way paintwork looks on a prototype when it has been damaged due to chips, scrapes, a collision or wear and the surface beneath shows through the top coat of paint. When we hear the phrase 'hairspray chipping' we often assume that it merely refers to a way of showing stone chips or paint flaking on a vehicle, but the application is much further reaching with the planks of flatbeds, wooden engine shed doors and walkways to name but a few examples of model features that have rocketed to the next level thanks to the technique.

The method involves painting a model in a perceived former paint job, livery or any other effect that you wish to show through such as rust, metal or naked wood. That coat of paint is then locked in using a lacquer followed by a middle layer of hairspray. A top coat representing the way the prototype would have been most recently painted is then applied. The now sandwiched hairspray prevents the top coat from adhering properly to the base coat, and when the top coat is scrubbed, scraped or scratched away (there are many methods for this part depending on the desired effect) the base coat then becomes visible without being destroyed by the scrubbing.