splais,
Thanks for the info.
As you said in your post, it's a special tank that fits the airplane. That makes it worth fixing. And the plastic weld might also be worthwhile to have in the flight box for at-the-field repairs. Sounds like it'd work on a hole as well as a screw expanded rubber plug would hold in the mouth of the tank.
Suggested Applications: Bonds rigid materials including ABS, acrylic, fiberglass, FRP, glass, PVC, SMC, steel, styrene, vinyl, and wood. Use for interior trim, fills cracks, bonds most plastic, bonds plastic to vinyl