I spoke with the Nelson Company yesterday to confirm some questions I had regarding Urac. According to them: URAC cures best at 70'. Curing beyond 70' will actually weaken the bond somewhat. They recommend a slightly coarse mating surface as it allows the glue to adhere to both surfaces better but toothing is not necessary. Also, air is not needed to cure URAC. So one can use shrink-wrap or the rubber band method to clamp mating surfaces together.