I have to decide which technique I will use …
(1) Hairspray Technique
(2) Salt Technique
(1) The Hairspray Technique takes more work. You spray on a couple of thin coats of a cheap hairspray. Then the top coat of paint which will be chipped. What paint you use is important. To some extent all paint brands will work since the water used in chipping is dissolving the HS not the paint. It DOES make a difference though.
Tamiya – works best. Tamiya acrylics do not dry to a solid vinyl layer of a shell. That means the chips are finer.
Vallejo – this is a vinyl acrylic. That means you get a vinyl shell and the chips are larger.
Lifecolor – somewhere in between Tamiya and Vallejo.
Since Tamiya are preferred it requires cranking up the airbrush etc.
(2) The Salt Technique is simpler. The rust undercoat is the same. With that dry you dampen the surface of the model, sift salt over it and when dry you spray the top coat on .. even rattle can will work.
The main difference for the modeler then is that with the Hairspray Technique you have total control over removal of paint exposing the rust underneath .. the chipping. The Salt Technique has much less control … you are sifting salt on a wet surface .. somewhat at random. When the salt dries you can go back with a brush and remove salt before you paint.
Now I have to determine which technique I want to use. I will probably go with the Hairspray Technique just because of the control over the chipping.