Anybody know of a dip that will clean brass almost instantly? Or at least in a few minutes? That is sold at the store or hardware store? I have 400 small parts that came out of the tumbler oxidized and need to be delivered today. This has not happened before so I don't know what happened. Thank You, Eric R Snow
Citric acid and phosphoric acid both do a good job. Try some cheap "Koolaid" in water without the sugar -- make it pretty concentrated.
Brad
Coke contains phosphoric acid. The drink, that is, not the white nose powder.
Leon
When I am cleaning rifle brass I first soak them in a 2% phosphoric acid solution, then put them in my tumbler and they come out very bright. They are pretty bright just from the soaking but the tumbling does a great final polish. Don't know what other sources are available but I have been using the Baqua Spa filter cleaner solution. First I use it to clean my hot tub filter, then I keep the bucket of solution around to clean brass.
Steve.
A phosphoric acid solution is available at most autoboby supply stores (NAPA was a source when they carried a full paint/refinishing inventory). It's a diluted, but fairly strong solution thats diluted further with water in different ratios for different metals.. usually, there are some examples on the label.
It's commonly referred to as metal prep in the trade. It's used to remove oxides and to etch bare metals prior to applying primer.
WB ................
vinegar and salt
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I havent specifically used this to clean brass, but I have noticed that nitric acid ( HNO3 ) does a pretty good job og cleaning up brass fittings and valves.. I work in the dairy processing industry, where HNO3 is widely used for cleaning..
Use a 2-3% solution in warm water and do this outside or in a well ventilated area, HNO3 makes some nasty fumes.. Dump the used solution in the sewer as it may produce some explosive byproducts..
The treehuggers are probably going to flame me for this, but dumping HNO3 in the sewer isnt really a problem since the pH in normal sewage tends to be on the alkaline side of 7....
We use approx 1.5 metric tonnes of concentrated HNO3 per 24 hrs just to get the pH in our wastewater below 9 as specified by the local sewage processing station
Dont forget gloves and goggles!
/peter
I've pickled brass items in warm sodium bisulfate solution (aka sparex acid pickle) before to remove the copper oxides, but I'd like to point out that when I did it, the parts did not come out with a bright yellow brass shine. They emerged from the pickle with a clean but dull reddish coating of copper which I buffed off afterwards. I'd imagine that to get back to bright brass color after this kind of dip you would need to tumble your parts or possibly give them a nitric acid drip just long enough to dissolve the copper. Other home methods I've heard of include vinegar and peroxide pickle, which may or may not have the same copper-coating issue.
-Adam
When doing this one might consider the effects of concentrated solutions on the house plumbing. Also this might not be the best approach if one has a septic tank....
Jim
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Right, at about 0.01 percent concentration. It may taste good, but it's not much use for metal etching.
Thanks Brad and all you others who replied so fast. I used phosphoric acid. I did mix up some sparex the night before and left one part soaking in it. Absolutely no effect. I believe the oxide coating formed during tumbling was different than what occurs from wxposure to air over time. Soaking in phosphoric acid also had no effect. But tumbling with phosphoric acid cleaned up the parts in about 10 minutes. ERS
Well... a 2-3% solution in small quantities shouldnt be a problem.. otoh.. if you want to be on the safe side dump it in a public sewer :-).. Or neutralise it with sodium hydroxide and dump it in whatever sewage you may have
Another dairy facility in the area had a "small" leak from a storage tank used for lye ( sodium hydroxide, used for cleaning ).. Ran straight into the separate sewers for rain water and into a small stream nearby... That killed a fish or 2 :-).. The company did pay for the cleanup tho..
/peter
Eric, if the sparex and phosphoric acid dips did not work, your "oxide" was probably not oxidation at all, but some other kind of coating. What color was the coating and what were the parts originally tumbled in that caused the problem? In my experience a proper (140 deg) Sparex Acid #2 bath will effectively remove red and black copper oxides, copper sulfate, carbonate, acetate and chloride, all of which can form on copper alloys outdoors.
-Adam
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