What hairspray did you use? How many coats? I think it can work with rattle can but it needs to light layers of paint. My experience with Tamiya paints and hairspray tech have been I needed more water, longer soaking time and to scrub harder when I used an airbrush. That drastically changes if I change up the paint to say Vallejo.

http://www.ipmseaglesquadron.org/ES-Forums/index.php/topic,1446.msg6924.html#msg6924

My experiance with Tamiya rattle cans and hairspray chipping, is also that it does not work, i think its the laquor in the paint that does not react to water

Best answer is to buy an airbrush, its a great investment