Type of keg for a kettle?

Looking for a 15.5 gallon half barrel keg to make into a kettle. I'm searching craigslist and just wondering if I have to be wary of different kinds of kegs that might not be good to convert as a kettle?

Reason I ask is I remember reading in some blurb that sanke(sp?) kegs are good for converting and something about straight sided, etc. Is there any issues with basically any 15.5 gallon half barrel I stumble across? Or do I need to look for a specific kind?

It really depends on your personal preference and your skill set. A lot of us have gone with the straight sided Sanke kegs because they are easier for us to weld on/modify. Some choose the path less taken. Check out:
https://www.homebrewtalk.com/f11/my-own-private-cl-keg-score-119743/
just down the page. If you look on here enough, you'll find just about every kind you can think of. Also, Sanke is kind of a generic term for the 15 gal. beer kegs you get for parties, etc. Cornelius or Corny kegs are usually the 5 gal. ones they used to put soda water in. Although, either can be different sizes but are still catagorized by the type of dispensing connectons they utilize. Luck - dwain

Sanke refers to the Tap Style.