The puffy yellow glue is polyurethane glue. The plastic was VERY slippery and hard to bond to the main effect is mechanical. The fins and centering rings are very light plywood - if I had it to do over I would fiberglass them first. Note the cardboard with the hole in it - this is where the rear cap goes on and I needed a rail button which needed a reinforced surface to keep it stable. The rear cap is held on by T-Nut secured bolts.