on several occasions I have taken all the bolts of a two piece casting, and the pieces were stuck together by the gasket. what is the preferred method of getting the two pieces apart?
You can use a rubber mallet sometimes. In some cases you can use a large screwdriver and pry gently between the two castings. The trick is to not damage anything.
What was it glued with? Permatex on both faces? Warm the stuff up with a propane torch. Try to seperate nearest the dowel pins like on a water pump. What are you taking apart? DO NOT just pound a screwdriver between the parts; imminent failure is the net result LOL. When I put stuff together, I may use some Right Stuff or an anaerobic sealant in the corners per se, but otherwise I use spray glue on one side of the gasket and neverseize on the other, like a thermostat. The stuff stays aligned, and you can re-use the old gasket a few times if its destined to come apart several times. ws