I have built 3 boats using secondary bonds only and never had any problems. The designers of these boats suggest it. Before cutting up any plywood, lay the sheets down flat and roller with epoxy. Once cured, sand then cut and build the boat. It is a lot easier than epoxy coating a boat once built. No runs on vertical surfaces and so on. I didn't do it on my Spindrift and now wish that I had. I start my next boat soon and will definately be switching back to precoating with epoxy before the build.