Are their any up dates on using polycrylic for your finishing methods? I am looking at these finishes for a new model..
I started using Varathane Water-base Polycrylic instead of Minwax because it IS fairly fuel proof if allowed to fully cure(up to a week). It can be used anywhere you'd use Minwax for a more fuel proof finish. Carver-Tripp also makes(made, I haven't bought any lately- same goes for Varathane. A gallon goes a Loooonnnng way).
I've used a simple system which gets nice results. I'm sure if you are as fanatic as top twenty fliers are the same procedure would work here.
Prepare the finished build. Sand block sand thoroughly to start leveling the surface. For 3/32 in balsa you'be got 1/32in to work with. With 1/16th wood less than 1/32in. If you put 1/32 over foam it better be darn near perfect before sanding.
Put on a seal coat/filler of varnish with your filler of choice-talc, stearates, starch. They all work.
Apply a complete coat to all exterior surfaces(you can put a fancy finish inside the tank/electric chambers). Sand it all virtually all off. A touch of black in a white filler coat makes low spots show up better, but shallow lighting works too. Touch up the low places.
Apply the base covering. I use very light(100 guage or less) clear laminating film. It's much quicker and easier than dope.
Apply another coat of filler, just enough to cover to minimize sanding. Sand it thoroughly while not nicking into the covering. Touch up any remaining low spots and check using shallow lighting to highlight any dips in the finish, Fix them and resand them.
At this point choose an appropriate base coat color. A very thin, but fully covering coat of light gray works for almost any color as a base. White helps light colors such as white(duh), yellow, and red, etc. Black covers anything.
I've used spray can paints with good results, since I'm a flyer. It's not worth my time for a few extra appearance points since I'm flying to have fun and don't practice much.
Allow rattle can enamels a few days, up to a week, to get completely hard. You can fly when they are full dry to the touch but be very careful about spilling fuel or too much exhaust on the paint.
Any other effective color paint approach will work if it has worked over other base coats.
Cheers! Everybody will use their favorite method anyway.
A full, autobody paint scheme with a clear, thin top coat is the cat's meow.