I'm in the process of painting a plane as you describe, fiberglas fuse and balsa sheeted foam - and then light glass - wings, etc. I have an old (30 years) Craftsman 100 psi twin cylinder compressor (Kind of looks like this one http://www.sears.com/sr/javasr/produ...cemldffidfmm.0 ), a Campbell-Hausfeld detail spray gun (from Lowe's at ~$30) and am using Klass-Kote paint ( www.klasskote.com ). So far I'm very happy with the results.