What are Sanke Kegs made of?

Rather straightforward questions, got my hands on a sanke for a keggle, and my little brother (who is a welder) is gonna cut it for me, but he wants to know if it is Stainless (which I think it is), or aluminum (which he thinks it is).

Cheers guys, and a big thanks to Steve for helping me get the final piece of my 10G puzzle!!

It's almost certainly stainless. There was a time when kegs were made from either aluminum or stainless, but that was a long time ago, and most of the aluminum ones didn't survive the test of time.

get a magnet and test it.

A magnet isn't necessarily a surefire test. Some stainless alloys do not have magnetic properties. Try gouging one of the rolled edges (away from the pressure vessel) with a dull piece of steel. If you can make a deep, definite gouge/groove, it's aluminum. If you only make a scratch, it's stainless.

Most Kegs are made of 304 Stainless Steel. There may be some aluminum kegs out there as Yuri pointed out.

You can tell an alluminum keg and a stainless steel keg from its appearence. Your brother being a welder, will know how to test it. Whether its alluminum or stainless steel is irelevent, because it doesnt matter when cutting it, whether by angle grinder or plasma cutter. Plasma cutters will cut any electric conductive metals, so it will make easy work of the alluminum, and grinders, well put a cutting disc on it, and call it a day.