Dreadnaught --

Lot's of good advice in the previous postings. Some thoughts:

Use the primer to reveal imperfections like pinholes and filled areas like fuselage seams

Sand the primer smooth like you want the finish coat to be. Good for looks and good for your masking tape to give a good seal for that sharply defined paint line. No tape will give a good line if the surface is not smooth -- paint will leak under the gap between the tape and the low spots in the surface.

Use a combination (depending on useage) of 3M 218 Green Fine Line Tape (for straight runs and gentle curves) and 3M 471 Blue Fine Line Tape (for smaller radius curves -- the outside of the radius can be stretched to a greater degree to remove the "excess" created on the inside of the curve - the tape lays flat then). With some practice yo will figure out how to work the curve a little at a time and spread the excess evenly and keep your nice curved line.

The Harbor Freight gun referenced above does a nice job with smaller areas (so do I...). I seem to have figured out that one pretty well. I need more practice with its bigger brother for shooting primer or clear coating -- I get some orange peel or too dry -- haven't figured it out yet --- perhaps some of the earlier posters will have some ideas for me.

Save an old piece of cardboard of decent size for practice. It can be used many times -- just shoot over the old paint. It's good for checking settings, size of spray pattern, etc. or just practice (expensive practice but I guess there isn't any substitute).

Hope this helps you -- now if I can just learn how to shoot the big gun I'll be in good shape.

Tom