How do you cut hinge slots in a sheeted foam core wing that has a 1/2" T.E. cap ... without damaging the foam ahead of the balsa cap?

HI Dennis,

I don't know of a way to put in the hinges with out going into the foam.  I do something very similar to Jim as far as making the hinge slots.  I use some type of course tooth X-acto saw blade to open up the slot (cannot remember the number) which is close to the thickness of the hinge material.  It is flat and fits into the big handles (not a razor saw).  Then I also use a metal finger nail file to fine tune it.  I found a centerline tool somewhere and I use some large scalpel blades to make the initial slit.  Goes pretty quickly, but I have never used one of the hinge slot cutting electric tools.

For the "hinge pockets" in the flaps/elevators I made some sanding jigs out of a couple pieces of ply the width and thickness on the pocket that needs to be made.  Double sided tape to attach 80 grit strips of sandpaper to them.  With a larger piece of ply to act as a "depth gauge", or stop, and a scrap of balsa as a handle, it takes seconds to do each pocket.

Big Bear

In reality that should have been considered when doing the wing initially.   Trailing edge peice should have been marked where hinges were to go.   Then scraps peices of balsa blocks glued in front of the trailing edge peice.  Of course the foam has to be notched out to clear the blocks.   Now this is done on wings in which the trailing edge peice is glued in place before the top and bottom trailing edge sheets are put on.  Don't forget to mark the ourside surface of the trailing edge where the blocks are.  Don't ask me to tell you why.  But, there has already been advice given for the wing that is already done.