Pic 1 shows how I recessed the 1/8 lite ply spar block into the wing half.
After the the glue has had time to cure, sand the tube flush with the 1/8" liteply spar block.
Pic 4 Now you can glue both halfs together with 5 min epoxy. A real lite coat is all you need. Making sure no glue gets insitde the phenolic tube.
Pic 5 showes me loining the to wing halves.