Clear Shrinking Dope.
Cellulose dope is typically used for finishing tissue covered balsa models, but because of it's unique ability to shrink tissue and nylon to it has multiple applications including sealing & waterproofing, surface smoothing, providing a protective coating and as a base layer for paints & coatings.
Tightens model aircraft fabrics and tissues to provide a waterproof satin finish, great for aircraft & marine models.