[Philbrew]

I have three 5 gal. corny kegs. 
  My first I bought from a neighbor that got out of home brewing 8 years ago.  It has Pepsi Cola Btlg Co stamped in the side. 
  The second is a new keg I bought from AIH.  Made in China IIRC.
  The third is a slimline Torpedo keg from Morebeer.  I think USA mfg.  It has 304 stainless steel printed on the side.

I recently received some Ball and Keg magnetic level indicators and while checking them out on the Torpedo keg I noticed that the ball (with a magnet in it) wanted to stick to the bottom.  So I used the capture magnet to check and found that the side was non-magnetic but the top and bottom formings were slightly magnetic.  Same for the AIH keg.  But the Pepsico keg was all non-magnetic.

I've always thought that 18-8 stainless steels (302, 304, 316) were non-magnetic.  So, here's the question for any metals expert out there...are these ends not 304 SS?  Or does the stresses of forming or machining make them partially magnetic?

And the follow-up question...if it's not the "good" SS, could iron ions get into the beer?

[hopfenundmalz]

Probably the workingof the steel for the tops and bottoms.
http://www.bssa.org.uk/faq.php?id=24

[Philbrew]

Probably the workingof the steel for the tops and bottoms.
http://www.bssa.org.uk/faq.php?id=24

Thanks Jeff.  I thought that must be the cause.