Is this corny keg salvageable?

[RyPA]

I got 2 corny kegs & a glass carboy at a garage sale 10 or so years ago for like $25. One of the 2 kegs I've never used and recently gave it a cleaning with a PBW soak overnight and some scrubbing. I got most of the residue that was in there out, but the bottom does not look that great. Do you guys think this is salvageable, or should I toss it? I was considering getting some bar keepers friend to see if it can clear up those marks. If this is no good, likely going to pick up a 6g torpedo keg.

 

[Dr_Jeff]

I'd use some really hot water, like 180 degrees or so and fill the keg up past the marks, then add a couple of big scoops of oxyclean and let it soak for a couple of hours

 

[soccerdad]

IMO bar keepers friend is worth a shot. Good thing to have on hand regardless. And one of these .. Get America’s Best Smiling Scrubber from Scrub Daddy today!

 

[Dr_Jeff]

the dip tube likely needs a brush ran through it as well

 

[bracconiere]

to me it looks like just rust? maybe the people that know about passivization?

https://www.harborfreight.com/1-qua...82_WnlACSd0Iqwstg62GyvKbEQ5gQJUxoC3XkQAvD_BwE
i don't know?

 

[RyPA]

I'm thinking rust, as I scrubbed it a bit, did a 24 hour PBW soak, a second 6 hour PBW soak, and it's standing it's ground

If it is rust, does that make this keg toast, or can I get it shined up and fill it with beer?

 

[bracconiere]

don't know...



maybe this would help

https://www.google.com/search?q=iro...akgEGMC4yMC4xmAEAoAEByAEIwAEB&sclient=gws-wiz
says iron oxide is soluble in dilute acetic acid?

 

[PCABrewing]

don't know...



maybe this would help

https://www.google.com/search?q=iro...akgEGMC4yMC4xmAEAoAEByAEIwAEB&sclient=gws-wiz
says iron oxide is soluble in dilute acetic acid?

For rust removal Oxalic acid or Phosphoric acid are better than acetic.
I believe one or both are components of "Naval Jelly".
You should repassivate after using rust remover.

Ooh, I just remembered, Morton Salt company sells a product called "Rust Out" that works pretty well for removing surface rust stains. It contains Sodium Bisulfate I believe and it smells like rotten eggs when it is working.
Might be worth a try as well.

 

[bracconiere]

well i just tried 50/50 mix of glacial acetic and water on some rust spots on cast iron....no love....

but with cast iron i can always cook on some oil to cover it up....

 

[soccerdad]

You can take rust off cast iron with steel wool.

 

[cyberbackpacker]

Get a stainless steel scrubby and Barkeepers friend. That will take care of it in no time and it will be perfect to use.

 

[Golddiggie]

Have you tried using a Scotch Brite pad on it? Yes, it would be work but if you got different grit levels of those, you might be able to remove what's in there. Then passivate it to keep it good. I use citric acid to passivate stainless here. Using a HOT solution (140-160F) shortens the time needed by a large factor. IIRC the document I read listed the concentration should be in the 5-10% range. I usually use 10% for what I'm doing (small items). I bought a five pound bag of citric acid off Amazon for pretty short money (IMO). Still got a good amount left too.
https://smile.amazon.com/gp/product/B000OZFECU

 

[Gusso]

You guys can't actually reach your arm to the bottom of a corny, can you? My arms are long but too thick. I barely get past my elbow.

 

[RyPA]

I can get an inch or so of my bicep in there but that's it, so I can hardly reach the bottom. I bought some BKF tonight, going to give it 30 mins of soak time and then try using a scrub brush

 

[bracconiere]

@RyPA if you do 'toss' it....i'll pay shipping to toss it to me....

 

[RyPA]

After a few treatments of BKF, the spots are still there. I guess if they survived this, they will not impact beer?

 

[Dland]

The beer will probably be fine. But if it was my keg, I'd get some kind of brush to those stains. Even light contact with a heavy brush could do the job after a proper soaking. Probably does not matter though.

 

[PCABrewing]

The beer will probably be fine. But if it was my keg, I'd get some kind of brush to those stains. Even light contact with a heavy brush could do the job after a proper soaking. Probably does not matter though.

They may be pits in the stainless.

 

[hopjuice_71]

I have had that at the bottom of the keg and I also cannot reach the bottom of the keg. Some BKF sprinkled at the bottom, a scotch brite pad, long spoon to move the scrubbie pad, and some elbow grease fixed it.

 

[RyPA]

I brushed it pretty hard multiple times, and did some brillo scrubbing. In addition to multiple PBW and BKF soaks.

 

[day_trippr]

An overnight treatment starting with 150°F 4-8% by weight citric acid will fry out the exposed iron (do not seal the lid!). Then thoroughly rinse, invert to drip dry, and allow air exposure to "grow" chromium oxide over the fried out regions.

fwiw, it's been noted countless times before on hbt, the two best acids for this are nitric and citric. Not oxalic (BKF) or phosphoric (Star San).
Fortunately citric is cheap and easy to handle. Nitric not so much

Cheers!

 

[RyPA]

Thanks buddy. Where does one get Citric acid? When I search on Amazon, I get food grade results

 

[day_trippr]

And the food grade powder is what I've bought from Amazon for exactly this purpose

Cheers!

[edit] This is what I've been getting the last few buys...

https://smile.amazon.com/gp/product/B00EYFKNL8

 

[RyPA]

Interesting that stuff you can eat can take off rust that PBW and BKF can't.

 

[RyPA]

Will the rust return? If this is something Ill have to do maintenance on I may just replace it. Or is this a one time deal?

 

[bracconiere]

Nitric not so much

only thing i've ever heard it being used for is making explosives.....

 

[day_trippr]

Theoretically, no. The rusted areas are defects in a field of otherwise nicely "sealed" stainless steel. So once you've removed the exposed iron particles the chromium content should do its thing same as the areas that were not afflicted by exposed iron and grow the chromium oxide that prevents the iron content from turning into iron oxide...

Cheers!

 

[bracconiere]

Theoretically, no. The rusted areas are defects in a field of otherwise nicely "sealed" stainless steel. So once you've removed the exposed iron particles the chromium content should do its thing same as the areas that were not afflicted by exposed iron and grow the chromium oxide that prevents the iron content from turning into iron oxide...

Cheers!

hey, out of curiosity...those rust stains on my cast iron went away after drying with the acetic acid scrub....where does the iron oxide go, and i ask to know how important the drip dry phase is?

 

[RyPA]

Would the 4oz package be enough for this job? I'd rather buy a new keg then spend $25 on acid to improve this one. I know, I'm crazy. But I could also use the extra gallon of space.

 

[bracconiere]

if you want to try it out....

https://www.ebay.com/itm/223588429245?epid=1731062387&hash=item340ee8adbd:g:mv0AAOSweXddLNdo
don't need the minimum order that caused me to stop shopping on amazon.....


and i mean it when i say, i'll send you a fedex label...just tape it on the keg....drop it off at the local dollar general.....

 

[RyPA]

I guess the better question is how much do I need to fix this keg?

 

[bracconiere]

I guess the better question is how much do I need to fix this keg?

there's still the question of "if it works".....for all i know after the acid soak, it goes up as gas...because i scrubbed, and scrubbed my cast iron with the vinegar...and the rust stain didn't go away until it air dried....so maybe just a gallon of white vinegar dumpped in it then let it dry?

 

[RyPA]

Ok I'll try vinegar since I think I already have that. If this doesn't work, I'll go with the 6g torpedo.

 

[day_trippr]

fwiw, iron oxide ("rust") fully reacted with citric acid: Fe2O3 + C6H8O7 = Fe2C6H2O7 + 3H2O
ie: yields iron citrate (a "salt") and water

Cheers!

 

[bracconiere]

Ok I'll try vinegar since I think I already have that. If this doesn't work, I'll go with the 6g torpedo.

the vinegar and citric are both carboxylic acids...just the citric has three, soo it'd be a safe bet....if vinegar don't do it, nothing will...

honestly i want to try this though before hand....

https://www.amazon.com/Sanding-80-3...ocphy=9030226&hvtargid=pla-766316794750&psc=1
https://www.ebay.com/itm/2245398083...dxg9Rfz:sc:ShippingMethodStandard!85650!US!-1
still pushing the price of the new keg though....

 

[RyPA]

Yeah, I already need the extra headspace that the 6g torpedo provides but I was going to try to get this corny to work. I'll try vinegar tomorrow and go from there. If this doesn't work and anyone is in NJ and wants this corny, let me know.

 

[IslandLizard]

Would the 4oz package be enough for this job? I'd rather buy a new keg then spend $25 on acid to improve this one. I know, I'm crazy. But I could also use the extra gallon of space.

IIRC, you need a 4% CItric Acid solution (by weight) for SS passivation. So to fill a 19 liter keg you'd need 760 gram or 27oz of Citric Acid.

If you only treat the (pitted) bottom, half a gallon (or 2 liters) should suffice, so 80 grams or about 3 oz.

By lying the keg on it's side you could passivate the sides with 2 liters of acid too, but only about 1-2" of the circumference at a time.

 

[OleBrewing]

Sand it out and call it good. Although I can barely fit my arm in one. I got all my kegs from the salvage yard. Created a drill attachment and scotch Brite and went to town with oxyclean.

 

[RyPA]

I could sand it. Do the interiors of cornys have an interior coating that I'd be losing? Or does it not matter

 

[bracconiere]

I could sand it. Do the interiors of cornys have an interior coating that I'd be losing? Or does it not matter

from what i've read the chromium in the SS aloy will oxidize and be fresh as new with some acid and O2....? or nickel or whatever makes it stainless....it's not cast iron with a carbon layer...it's got a oxidized layer....i think?