Fermenter project

[HighVoltageMan!]

if a magnet sticks to the side it is not 304

Not necessarily. If 304 is formed or worked cold, it will develop magnetic properties. If it needs to be non-magnetic, further processing needs to be performed. I believe it needs to be heated and slowly cooled (but I'm not 100% on that).

The reason I bring it up is because I panicked when I bought a new keg. It was made in China and a magnet stuck to it. I thought I was ripped off until I tested a German keg and realized it was magnetic too. After some research I found the answer and I calmed down. 316 is less prone to this, but 304 can be mildly magnetic without a problem. I also noticed the parts that were bent were more magnetic than the parts of the keg that were straight and minimally formed.

I have since avoided Chinese kegs, the German and Italian kegs were higher quality and not that much more expensive.

 

[Minbari]

Not necessarily. If 304 is formed or worked cold, it will develop magnetic properties. If it needs to be non-magnetic, further processing needs to be performed. I believe it needs to be heated and slowly cooled (but I'm not 100% on that).

The reason I bring it up is because I panicked when I bought a new keg. It was made in China and a magnet stuck to it. I thought I was ripped off until I tested a German keg and realized it was magnetic too. After some research I found the answer and I calmed down. 316 is less prone to this, but 304 can be mildly magnetic without a problem. I also noticed the parts that were bent were more magnetic than the parts of the keg that were straight and minimally formed.

I have since avoided Chinese kegs, the German and Italian kegs were higher quality and not that much more expensive.

My ss brewtech are slightly magnetic too. I believe they are 304

 

[JVi]

should be good to go! give it a nice spray with acid, rinse it and then clean it like you would normally and it should be fine.

fun fact. mirror polished is actually not as good as just straight rolled ss. the polishing is actually a ton of tiny scratches.

This is true

 

[Bigbre04]

meh i have seen large scale brewery equipement that was "304/316" be magnetic and have serious problems like cracking and corrosion issues. these were "cheap" chinese tanks from 10 years ago. since then the chinese have vastly improved their processes.

just did a little reading and it seems that 304 can become slightly magnetic when cold worked and still maintain its corrosion resistance. but i think that it becomes more brittle from the "cold working" process that causes it become magnetic. the brittleness causes cracks to form more quickly from heat cycling the tank and pressure.

I was mainly mentioning checking welds because not all welds are done properly they could use the wrong or cheaper "ss" in the weld rod and it cause problems.

the tanks i was referring to were 20 and 40 bbl tanks that had serious issues with leaking, especially around where the legs and supports were added. they also had some bad welds internally. My buddy is a sanitary welder and spent a lot of time fixing those tanks.