I think the white glue came from me. I don't know if it will work with polyspan. It is a trick to make the heat sealing films stick better. If they don't stick to fiberglass or epoxy glue joints or fuel proofing you can thin any white glue or carpenters glue with water, paint it on, let it dry and the covering sticks. I have done this on problem areas and I want to try it on the entire model. I doubt it would cause warping because you don't put that much water down per coat.