How do I remove tarnish from stainless steel fittings?

[pickles]

I purchased a bunch of Swagelok fittings for my brew rig but they are covered with gray tarnish. They are mostly 316 SS, but a couple Parker A-lok fittings are 304. I don't want to scrub these by hand and have tried soaking in oxyclean which removed the dust on them. Is there something I can soakk them in to remove this? Preferably stuff not too nasty and perhaps found locally; maybe that's too much to ask for.

 

[GilaMinumBeer]

It's likely a tarnished lacquer coating of which not much can be done.

 

[pickles]

Are swaglok fittings finished with lacquer? I just scraped the outside and nothing flakes off.

 

[Bobby_M]

Pictures? You sure it's not that grey anodized finish that they do on the compression nuts?

 

[kmack747]

What you are seeing is fine its the natural oxide passivisation that occurs on stainless. This thin film helps prevents corrosion.

In this pic the The right side has been passivated in nitric acid

 

[pickles]

I'll try to get some pics tonight. I have some of the matte gray compression nuts and this doesn't look the same. If it's a passivated coating then how's come some other valves and fittings I've had for years are still shiny? I figured they got washed in something prior to me getting them and it tarnished them. Google searches turn up ammonia as a good cleaner for ss. Maybe I'll try one in some dilute ammonia solution and let it set outside in the garage.

 

[Photomask]

Swagelock fittings are not laquered or have any other treatment to them. The only addition is paraffin on the threads of the coupling nuts to prevent galling when tightened. Leave them in phosphoric acid for an hour or two, it is often marketed as Metal-Prep to treat steel prior to painting. Home Depot, as well as other home centers and paint shops should have it. (Phosphoric acid is used to passivate stainless by leaching iron out of the surface lattice structure of stainless steel, providing a chromium rich surface that increases it's corrosion resistance. The passivation process is enhanced by the addition of a DC electrolytic current.) If that doesn't do the trick then they have been exposed to something and a strong solvent such as acetone may remove it. If you reload, another option would be to throw them in the vibratory brass polisher for a couple of hours.

 

[jsguitar]

Sorry to bump an old thread but I just received five of these from an Ebay purchase and was wondering the same thing. The listing I bought from didn't have actual pictures so I had no idea. If you do a search on eBay for them there are some actual pictures of this showing the compression nut as a matt grey color. Is it an anodized finish like Bobby suggested? I actually thought they were severely tarnished too and lightly sanded the outside of one of them. The entire nut including the threads is a dusty grey color. Weird.

Edit: mine were all Parker 1/2" 316 SS compression fittings

 

[lewybrewing]

Did you try "Bar Keepers Friend"? It is amazing stuff for stainless

 

[jsguitar]

Did you try "Bar Keepers Friend"? It is amazing stuff for stainless

Not on these fittings yet but I use it on everything else. I'm not sure what it is actually. They appear to be manufactured like this.

Sure enough when I did a search on EBay I didn't see any with pictures. Here's what I'm talking about from the Parker website.

http://www.parker.com/portal/site/PARKER/menuitem.7100150cebe5bbc2d6806710237ad1ca/?vgnextoid=f5c9b5bbec622110VgnVCM10000032a71dacRCRD&vgnextfmt=EN&vgnextdiv=&vgnextcatid=12536&vgnextcat=FERULOK+24+DEGREE+FLARELESS+BITE+TYPE+-+STAINLESS+STEEL+%28SS%29&Wtky=FITTINGS

I'm going to try to contact them about it if I can.

 

[passedpawn]

BKF. Make a paste, apply with a rag, let sit for 10 minutes, start scrubbing.

 

[pickles]

I did exactly as Passespawn suggests. It took forever but worked well. I also found a stainless steel round wire brush that plumbers use to clean inside fittings worked well on the insides. Just remember that wire brushes must be stainless! Be sure to report back in a month when youre done scrubbing

 

[jsguitar]

I did exactly as Passespawn suggests. It took forever but worked well. I also found a stainless steel round wire brush that plumbers use to clean inside fittings worked well on the insides. Just remember that wire brushes must be stainless! Be sure to report back in a month when youre done scrubbing

Crap. I guess I have some work to do.

I wonder why just the compression nuts come that way? Never seen SS look like that.

Thanks.

 

[orangehero]

BKF is oxalic acid. Soaking in phosphoric acid would probably be easier and faster. They sell gallon jugs for rust removal at the hardware store.

kladue says:
"50-50 mix of citric and ascorbic acid in water, heated to 180 deg. F and circulated, this is the method of choice these days in the food and pharmaceutical piping system passivation. Solution is circulated until soluble iron content remains constant which is the signal that the passivation is finished."

 

[jsguitar]

I just got off the phone with a guy at the Parker company and he said what I had was what they call "moly" (for short) coated and he said he would not recommend using these inside a Boil kettle or HLT. For running fluid inside it's fine because the liquid never touches the nut. He didn't think Id be able to get it off. It's really a dark grey coating that will leave a grey smudge on paper when rubbed against it so I'm not sure if its the same as what Pickles was talking about or not.

Here's the link that I bought from that someone on this site recommended for reference (not their fault btw)The seller has them listed as a replacement for a Swagelok fitting that would've worked fine:

http://cgi.ebay.com/Parker-Male-Connector-Part-SS-8-8-FBZ-SS-810-1-8-/330539711913?_trksid=p5197.m7&_trkparms=algo%3DLVI%26itu%3DUCI%26otn%3D4%26po%3DLVI%26ps%3D63%26clkid%3D1830614999097181915#ht_500wt_689

That's what I get for trying to save a few bucks. I also sanded most of the outer coating off of one so I guess I'll put it in the "why the hell did I buy that thing" bin and try to resell the rest.

I'm also going to track down that thread and put a note there.

Edited to clarify