I have a deck delam that took off a decent bit of foam. However the foam came off in chunks here and there leaving about an 8" circular area that is at its deepest, roughly .5" less thickness than the rest of the deck. Can I use that much Spackling to fill in such a large area? And just ro let you know, making a foam patch would be difficuly du to the nature of the depressions.
Spackling doesn’t really have much structure to it. I can fill small holes if you cover it with resin but for the kind of repair your doing I’d use micro balloons with resin to fill then glass over.