RE: Automotive paint
This painting has me on a side track now too. I had trouble with lusterkote over in the kit building section. I am going to do some experimenting this winter to find a cheap paint that is fuel proof. In High School and early 20's I was fairly knowledgable about automotive paints. I worked in my dad's body shop, painting my buddies vehicles and fixing their crashes to earn my gas money. But that was about 30 years ago and I know there have been changes in paint since then. Back then there were mainly two kinds of paint, acrylic lacquer and acrylic enamel. The hardner you are talking about for enamel was not mandatory but was usually used, it made the paint a little harder than without. Vehicles painted with enamel without the hardner would sometimes start to look chalky after 3 or 4 years. Acrylic enamel was very sensitive about what could be sprayed over the top of it unless it had cured for several months, it could only be top coated with more acrylic enamel. Lacquer on the other hand could be top coated with almost every kind of paint, hence all primer back then was a lacquer base. About that time Imron came on the scene. If I remember right it was a polyurethane, that had to have hardner or activator added to make it set up. From all the advertising blitz back then I gathered Imron was developed for the aviation industry. I suspect Imron is the same type of paint that people talk about getting from Radio South, read expensive. But Imron paint was high priced too, 30 years ago a gollon of clear was $75, were as a gallon of acrylic enamal by ppg was probably $20 or $25. I got into the custom painting a little with the murals, flames, fish scale, sort of thing.I used acrylic lacquer to make all the designs because it was easy to work with, blended into other paints good, dried fast, and cheap. Then I would clear coat everything with Imron clear after sanding lightly with 600 grit. I saw a pickup 15 years after I had painted it that way and other than all the rust that was attacking it, it had the same shine as the day it rolled out of the shop.
Darn, I am rambling, back to the point. Just about everything will attack lacquer so I am going to start expermenting with acrylic enamel with hardner. If that doesn't work I will go with the lacquer color with an Imron (polyurethane) type clear over the top. That way I just have to buy an expensive clear and use the cheap lacquer for color. I know this didn't answer your question, but maybe together we can find cheap automotive paint solution.