with a ruler, caliper, thickness gauge, measuring tape, it depends on how thick, or thin it is. same thing goes with measuring the thickness of anything
Metallic aluminum is produced commercially from the mineral bauxite, a hydrated oxide of aluminum. The top five bauxite producing countries (in 2007) are Australia, China, Brazil, India and Guinea....
External diameter minus internal diameter will get you the difference and then you have to divide by two to get the wall thickness. (as the difference in diameter accounts for both sides of the...