My pops had a kit plane that had its fuel tank fiber glassed and foam encapsulated to hold the tank in place. Why, lord only knows, the plane was made of wood, carbon steel, fiber glass and other stuff. To pass inspection, the tank needed to be removed, it was alot of work removing the foam fill and cutting and hacking into glass fiber, but once it was done the tank was free to be replaced, alot of work for this kit plane. So good luck!