Welcome Mark
As you will already have realised, your questions will be answered with a range of insanity, madness, mayhem, truth, humour and occasionally seriousness!
Yes you definately need to seal balsa before painting, either several coats of sanding sealer or a couple of coats of epoxy, there is plenty of info on the forum on this.
One thing you need to be aware of.... PHOTOS ARE COMPULSORY!
Ian