Jb Weld on aluminum intake

You want to make sure you provide a very rough surface for the material to lock into. Up to and including using a small drill bit to crater the surface at different angles. If you just lay the epoxy on top of a crack, it will likely pop off and go into the head due to the different expansion rates of the intake and glue. Give it a good surface to hang on to and it will be there for a long time.