i blow my edges clean with compressed air, apply wood glue out of bottle, use a 1" cheap brush and spead evenly, then use 1 1/2" finishing nail from air gun to put together, then i put a bead of wood glue in all the corners, let dry then caulk, on boxes i double up on i stagger the joints, and use 1" finishing nails with excess wood glue, for mounting sub, i spend the extra time and predrill for t-nuts, CA them in place, never had a problem, can tighten the subs 100% tighter than just screwing in to the wood.