Originally Posted by addictedtoplanes
So this past summer, I acquired a well loved .40 size Hangar-9 J-3 Cub, with the Hangar-9 .40 size floats. They had considerable hangar rash, so I've spent most of this winter repairing them for the summer. They are balsa, covered with Ultracote. I am worried about water leakage in the seams. Do any of you guys have any ideas about sealing the floats, short of stripping them completely, and fibre-glassing them?
I believe the current H9 Floats have a fiberglass "skin" on the bottom surfaces. If you do not see cracks at the seams, the UltraCoat covering is not prone to leakage. On other balsa floats which are covered by the builder, 1/2" strips are run completely over edges everywhere there is a balsa seam and especially at the keel before final Monocote or UltraCoat covering to give a bit more durability and covering thickness. In my experience, in the absence of actual damage to covering, leakage has never been an issue except at penetrations through the balsa, such as at strut mounts and rudder mount screw at the transom. At those penetrations, I apply a little marine adhesive/sealant around the attaching screws or bolts.