Hi Colin,
Cascamite is an amazing product, my really early experiments with nylon stockings in the late 60's and early 70's (Long before the foam ones) used cascamite powdered glue which can be mixed from runny and paintable, right up to thick gap filling. We used to knock up a balsa flatty racing boat (Marksman by Phil Connoly and the like as well as some Vic Smeed designs.) Cover them with tights and two or three coats of cascamite, unbelievably strong and totally waterproof. Dried hard like a drum skin. Works well on paper, nylon covering, and F/G laminating fabric although a new material...Frostguard from a garden centre is incredible for covering, costs about £5.00 for a massive 10m. roll.
Happy days!
Ron.