Using depron 3mm laminated to 6mm only got two boards so used this to fuse sides.
Using foam boars without paper and laminate to have 8mm. Sanding the parts with 60 sand paper could elimanate waves in material and resuce to 6mm. Mixing several build technicks so foam build with balsa build, foam cutting for wings and glassing.
You can download the seaplane drawings for radio control on the left side of the site.