pickling paste or gel for stainless?

Hey, folks...

I recently had some fittings welded to a keg and I boiled some water in that keg last night for the first time to make sure everything was leak-free. No leaks anywhere, but when I was done I found that the area around the welds on the inside of the keg are now rusty.

I've been reading about what I can/should do about this this morning and have seen some information about using pickling paste or gel, but I wanted to make sure I understood the stuff.

A couple of references I have read say that the stuff will not only give the protection I want but will also clean off the existing rust if there is some there. Is that true? Or would I have to clean the stuff first and then use the pickling paste/gel?

Also, does anyone know of a brand name for the stuff and where I can find it?

Also, are there any other alternatives to this stuff? I saw a suggestion to use barkeeper's friend on one site, but it wasn't clear if this was just to clean the rust or to prevent it.

Any ideas, ladies and gents?

BKF will clean and help passivate the stainless, which prevents future rust. Use a scotch brite pad that has not been used on iron or carbon steel.
Passivation is commercially done with nitric acid. BKF has oxalic acid.
http://www.howtobrew.com/appendices/appendixB-1.html

Awesome... thanks! I've got some brand new scotch-brite pads and BKF in the garage. Time to scrub the crap out of this. I don't know how well I can clean it, though.

Everything was welded only on the outside, so the inside is just rough, rocky bleed-through or burn-though or whatever you call it. That's where the rust is. The texture might make it hard to scrub clean.

Walker said:

Awesome... thanks! I've got some brand new scotch-brite pads and BKF in the garage. Time to scrub the crap out of this. I don't know how well I can clean it, though.

Everything was welded only on the outside, so the inside is just rough, rocky bleed-through or burn-though or whatever you call it. That's where the rust is. The texture might make it hard to scrub clean.

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That's known as sugaring. It from not having the back side protected proper from the heat. IMO, your gonna want to get that stuff ground down and smooth just for future cleaning. If have a go at it like it is its just gonna tear up you scotch brite and maybe your fingers.

Just like mentioned above about contamination. Grind it down with something that hasn't been used on any mild/carbon steel.

You can also fill it up and use some citric and ascorbic acid in the water. Get it warm (120-140 ish) and let is sit for a while keeping the temp.

GreenMonti said:

You can also fill it up and use some citric and ascorbic acid in the water. Get it warm (120-140 ish) and let is sit for a while keeping the temp.

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I assume I can do the same with the BKF? Put some in water, heat it up and let it soak?

Grinding this smooth would be a problem because I don't think I can reach the under-side of two of the welds (one is a 1/2" coupling and one 1/2" nipple, both are located fairly low on the wall of the keg).

Walker said:

I assume I can do the same with the BKF? Put some in water, heat it up and let it soak?

Grinding this smooth would be a problem because I don't think I can reach the under-side of two of the welds (one is a 1/2" coupling and one 1/2" nipple, both are located fairly low on the wall of the keg).

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I am not sure about just adding water the BKF. I don't think it is concentrated enough. With the citric and ascorbic acids, you control the amount. So you could make it really acidic or not so much. The nice thing about your fittings being low is you don't need too much water. Just enough to cover them by about 2". I say 2" cause of the heat affected zone, plus a little for good measure and evap.

I would grind what you can. A small mirror like the ones used by auto mechanics will aid in your ability to see the underside. That and a dremel tool or a smaller die grinder.

I know all about the boil killing the nastiness. I'm just trying to get you to go the extra mile on your equipment.

I agree with GreenMonti and I need to do the same with my kettles, grind down the sugaring. It will be difficult to clean near the bottom side of the weld because it's near the floor of the keg. I did not know you had sugaring, it looks crappy. Here is mine:

I don't know what you call it. Sugaring? Sure, sounds good to me.

I just made a paste of BKF and smeared it on everything and let it sit for a while, then scrubbed it off with the scotch-brite (which did indeed shred). I'm going to try more water later to see what happens. It's pretty clear of rust right now... Just dark blue/black like when I picked it up yesterday.

I'll get some pics and post them, too.

Couldn't find the digital camera and my phone takes pretty miserable pics, so no photos to show.

But... I boiled more water in the keggle last night. New rust formed around the weld sites, but not nearly as much as had formed the first time, so the BKF paste I put on seems to have helped.

I bought a couple new grinding stones and stainless steel wheel brush for my dremel as well a large hand-held stainless brush and am going to give it all a good working over tonight and re-apply the BKF.

Almost there.

I went crazy on it with the stainless steel brush and put another thick paste of BKF on it for 10 or more minutes.

I've had water going in there for over an hour and there is just the *teeniest* bit of rust on it now.

Compared to the first time, I'd say that over 90% is gone.

Sweet.

Walker said:

Almost there.

I went crazy on it with the stainless steel brush and put another thick paste of BKF on it for 10 or more minutes.

I've had water going in there for over an hour and there is just the *teeniest* bit of rust on it now.

Compared to the first time, I'd say that over 90% is gone.

Sweet.

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This is good info.

I'm gonna bring this back from the dead.

Walker - Did it ever stop rusting, or are you still dealing with that 10%?

Have you noticed any effect on your beer?

tasq said:

I'm gonna bring this back from the dead.

Walker - Did it ever stop rusting, or are you still dealing with that 10%?

Have you noticed any effect on your beer?

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the welds no longer form any rust at all. I get a little rust on the electric heating element base (not stainless... not sure what it is), but no rust on my welds.

I haven't noticed any issues with the beer either.

Walker said:

the welds no longer form any rust at all. I get a little rust on the electric heating element base (not stainless... not sure what it is), but no rust on my welds.

I haven't noticed any issues with the beer either.

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Thank you!