Hi Jeff, It’s a rather simple method actually. With the purpose of getting a chipped paint effect one needs to softly moisten the primer/aluminium painted surface and then losely apply kitchen salt. Some countries have a rather refined, small grainy salt while others tend for a much chunky salt grain. Either work fine, though the finer grain gets you smaller effects obviously.
Then, after the salt and surface dries, move to the next paint coat process, and as soon as possible (but with paint already dry) use a old toothbrush, cottonswab or stiff brush, again moistened with water to scratch the areas where the salt was applied. Go easy with the water amount. Too much ruins it, too little gets the job too tedious. I used acrylic paint sealed with enamel varnish over the primer coat only. The second paint coat, again acrylic, had no varnish applied.
Personally, I’ve not yet used this method because I have some “chipping effects” AM products that I feel very comfortable using so far, but did try over an old model a few years ago just to see if it works...and it does
