Cracked aluminum can be adequately repaired without welding using an epoxy embedded with aluminum. The aluminum particles contained in the epoxy will adhere to the cracked part, creating a permanent bond that will hold up in most situations. To ensure proper adhesion, you need to prepare the surface of the cracked part, as contaminants will interfere with the bond made between the aluminum epoxy and aluminum part. The amount of prep work required will depend on the type of cracked part you are repairing.
Apply the degreaser to the cracked aluminum part and allow the degreaser to remove the grease from the aluminum part.