Hiding Finbox, which glue?

I’m going to build a new wooden board (see: https://www.woodboardforum.com/forum/design/workshop-tool-ideas/6409-8-3-pintail-foam-in-frame-project/page2). It will be an 8’3’’ pintail with a wooden balsa frame (but I want to fill the voids with sprayfoam). For the finbox I do have a massive balsa block already in place, where I set the longboard box into, using epoxy.

But after the box is installed, I want to veneer deck and bottom with a 0.6mm wooden veneer, which will be vaccuumed onto. I usually use PU glue for veneering under vaccuum, but I’m afraid the glue will not hold on the flattened and roughed surface of the finbox, which I want to hide optically. I never vaccuumed veneer using epoxy, and my epoxy has a set time of at least 12-18hours, which would mean, that the vaccuum compressor would have to run that long. Althoug I believe, that the compressor would not harm, its a quite small, but very good one, I do not like the idea of vaccuuming for a day… and even epoxy may not hold very good on the plastic of the box. There should not be real mechanical stress on the connection, the box will sit firmly in its own slot, but I’m afraid that the veneer will detach someday during installation and removal of the fin.

After veneering, the entire thing will be laminated using epoxy resin and glassed, but as light as possible…


Any Ideas, how to, or which glue to use?

Just an upfront warning: I do not do veneer boards so all this is ideas. I do cap the boxes on my EPS boards with glass and epoxy. Sometimes I tape off the slot and a razor blade like a cut lap and sometime I just let it cure and then use a trim router and bit.

The first thing I would try is an experiment to glue the .5mm veneer to the finbox with all the glues you have at home.  I would take some scrap pieces and glue them to the bottom outside of the box after sanding it lightly first. See which one sticks the best and go from there. 

Another idea is to shave the top outside of box down to 1 or 1.2mm less than normal installed height then cap with .5mm veneer. After that is glued and trimmed, place it into board, flush with frame and foam, and cover entire bottom with the .5mm veneer and PU glue aready planned. Then go back with a trim router and open up the box, perhaps with a small bevel so the veneer is not catching the fin. This would allow you to use epoxy (if that works best) on a smaller section that could be weighted overnight and not have to adjust your bagging time for slow epoxy on the rest of the board.

Looking forward to seeing the result.

One issue that must be addressed is the potential for exposed edge grain along the edge of the box slot.  Balsa is pretty bad at wicking water in to the grain.  Maybe a slight recess along that edge, filled with epoxy would do the trick?

I would also apply some wax and maybe clay to the inside of the box.  It might make the clean-up easier.