Bill, like so many of us, your a perfectionist. Don't let others "that's good enough for me" spoil you drive for your work to be the best it can be. When your work then is compared to others, you will sit at top of the pyramid of quality of workmanship.
Because the way ply wood is sliced, and made, it's my personal experience that determines nothing short of a at least a thin sealer coat is required. This allows total control over the finished produce.
I used sanding sealer for years on my model rockets. It adds weight, and shorten flights true. But on the launch pad, when the crowd is around your rocket, you sit with a smile while others have a smug look.
John E. Adams<br /><a href=\"http://www.woodys-workshop.com\" target=\"_blank\">www.woodys-workshop.com</a>