RE: Sealing and Painting Balsa
While not your preferred method, glassing is going to be the fastest way to seal the balsa and add some strength to boot. Unfortunately at this point it is really not an option as epoxy resin is not going to stick to paint. With what you have now, I would cover with one of the iron on fabric coverings and then paint. Can I inquire as to why you have no interest in glassing?