1st Keggie trial ends in rust???

[wagontrash]

So...I've been putting my gravity-feed AG system together for the last few weeks. Just got my three keggies back from the welder-dude three days ago. Of course, I couldn't wait to play. I leak tested them, no problems (whew.) I then put all the fittings / gages / tubes / thermos in and gave them a 'final' cleaning. After that, I decided I would completely fill them to the brim, and boil the crap out of them. (no real reason, other than I wanted to...) anyway. Everything worked just great, no leaks, the pickup tubes all left me with just the center-ring barley full of water, it all looked great. Put them upside-down in the workshop to dry, and went on to other parts of the system.

However...

On the inside of all three kegs, all of the welds are rusted!!! Some of the SS fittings are rusting as well!!!!

HELP!!! I haven't even had a chance to 'use' these yet. WTF-Over????

 

[Liquidicem]

Your welder may have use a carbon steel bush to clean up the welds. This embeds small pieces of carbon steel in the welds that will rust forever... I'd talk to him about how he did the work and the clean up.

 

[wagontrash]

I am planning on calling him in the am. What is puzzling me, is the rust is only on the inside and not on the outside as well??? Any thoughts on how to resolve (even if it's not 'easy')?

 

[Bobby_M]

The inside rust just happens to be where moisture lingers longer while the outside stays drier. I would guess the outside would rust over time as well.

 

[stevehaun]

No worries. Go buy a green 3M scrubbie and some Bar Keepers Friend (oxalic acid). Scrub off all the rust and the areas around the welds and fittings - inside and outside. Rinse and dry well. This will passivate the stainless steel. It may take a few times but it will be ok.

 

[JoSeR]

+1 for green scrubby and barkeepers friend.
I've heard lemon juice works as well.
You're 3rd option is to leave the recently cleaned areas dry and exposed to air for a week or two and it will passivate all by itself.
The trick is to get it good and clean before you treat it
Google passivation stainless steel and it will tell you all you need to know, including home methods

 

[Special Hops]

I'm in the biotech industry and we use citric acid all the time to passivate. So +1 on the lemon juice.

 

[Bobby_M]

The repassivation will be effective if it was just a high heat problem but what if the guy used a steel wirebrush? I think at that point you just have to wait for all the particles to rust their way out.

 

[wagontrash]

Found this that seems to describe the exact problem/solution. Thanks for the hints/help!!!

http://www.howtobrew.com/appendices/appendixB.html