Cleaning copper – Results and pictures are IN !!!

Woody_Woodchuck · Post by **Woody_Woodchuck** » Wed Jan 30, 2008 5:09 am

Howdy. Ever wanted to see how a certain technique or formula cleaned copper? Here’s your chance. I’ve already tried a few and am open to others. I’ll give them a try this weekend and have a picture of the before/after results posted. It’ll be a nice comparison so we can see how all of them stack up next to each other.

I’m restoring a 20 gallon copper pot I built about 14 years ago using 20 ounce copper. Through bad storage practices it got oxidized, big time. The inside is heavily crusted in blue and pitted underneath that. The bottom and lower sides had many holes and have been cut off. There was no patching to them, they were trashed. I started cleaning the inside and might have to cut more off the bottom part as the pitting is really deep.

Rules? I’m not open to Brasso or some other store bought product. Mostly because I’d have to buy it and never use it again! I’m open to pretty much any other chemicals that I might have laying around in the cupboards. Natural products get more points in my book as I can eat the leftovers.

So far I’ve already done test spots of:

Vinegar, flour and salt paste
Vinegar soaked paper towel
Catsup
Crest Toothpaste
Some other red-paste whitening toothpaste
0000 steel wool
Muriatic acid 5%
5% Muriatic acid diluted (5 to 1)

All products were spread on and allowed to soak for 15 minutes before being scrubbed with a plastic brush. Except for the 5% acid, which I wiped on and got off pretty quick as it really ate down to the copper mighty fast. So far it’s a clear winner.

I have others I'm going to try: lemon juice, baking soda/water paste, salt/water paste and Labrador retriever drool. So come on and let me know what others you’d like to see!

- Woody

Post by **HookLine** » Wed Jan 30, 2008 5:25 am

Sulphuric acid
Hot backset straight from the still

Woody_Woodchuck · Post by **Woody_Woodchuck** » Wed Jan 30, 2008 6:57 am

Unfortunatly one I can't try right now. I don't have another working pot to get any from, sorry. I can save a piece from the cutoff section and try after I get it up and running!

Post by **HookLine** » Wed Jan 30, 2008 7:08 am

No hurry.

Post by **HookLine** » Wed Jan 30, 2008 7:27 am

[Double post]

pintoshine · Post by **pintoshine** » Wed Jan 30, 2008 7:54 am

I have a couple more recommendations to try. I got these from a clock restoration site.

Household ammonia. Reacts well with patina.

Equal parts white vinegar and household ammonia. This reacts to create ammonia acetate, which is an extremely nice copper cleaner. It removes green and brown patina well. It is not very effective on copper oxide though.

Muriatic acid straight from the jug and 32%.(my favorite for cleanning after annealing) and any diluted strength with heat and time will work.

A one to one mixture of 3% hydrogen peroxide and muriatic acid. USE EXTREME CAUSTION, this is what I use to etch circuit boards)

I have used all of these with varying results. Removing the black and red oxide from annealing is easiest with straight muriatic acid. It leaves the best finish and is the most expedient. I have not used it on green or blue patina yet.

I had a lot of trouble out of sulfuric acid leaving residue which causes a lot of blue sulfate after the surface dried. No amount of flushing seemed to prevent this from happening.

Polishing is another subject but I have excellent results using the gray buffing stick(emery) and a 1 inch wide round, cotton polishing wheel in the drill. this creates a near mirror finish. I am buying a new bench grinder just for this task soon. I would like to be able to run one pad for gray and one for red polishing compound.

One of my next videos is removing the red, black and brown material left from annealing. It looks like magic but is just chemistry in action.

Post by **Usge** » Wed Jan 30, 2008 8:42 am

Not just lemon juice. Lemon juice and salt.

byacey · Post by **byacey** » Wed Jan 30, 2008 9:20 am

Ammonium Persulfate dissolved in hot water. This is used for etching copper PC boards in the electronics industry and will leave virgin copper behind. Must be rinsed out with cold water for clean up.

BW Redneck · Post by **BW Redneck** » Wed Jan 30, 2008 4:14 pm

Usge wrote:Not just lemon juice. Lemon juice and salt.

I have something to add to that.
If you're doing a large surface, then slice a lemon in half and rub the cut surface with salt and use that to scrub. I've heard that it works, but I've never tried it. Lemons are comparatively expensive here.

Post by **azeo** » Wed Jan 30, 2008 6:33 pm

using a *hot* solution works great too, especially the milder acids. Lemon juice, vinegar and citric acid work great either together or on their own if no hot backset available. Many of my fittings I simmer in a stainless saucepan and it's also possible that the dissimilar metals helps it along too through galvanic removal. They work well and being food based, easy to clean and low contamination.

Have tried salt in the acids, all that happened was that if brass fittings were in the pan with copper, they seemed to get a thin veneer of copper, which could be good!
Look forward to the results, great investigation!

Post by **Dnderhead** » Wed Jan 30, 2008 6:59 pm

I Would say acid ate zinc and left copper giving it more copper look

stoker · Post by **stoker** » Thu Jan 31, 2008 6:13 am

can you give the bad things for copper a try too?
(like strong nitric acid, bleach, ...)

pintoshine · Post by **pintoshine** » Thu Jan 31, 2008 7:08 am

Strong nitric acid?
If you were merely being sarcastic, then maybe a smile would have clued us in.

stoker · Post by **stoker** » Thu Jan 31, 2008 7:21 am

I could have chosen my words better

I saw it more like this: test different concentrations, and see what reacts with copper, and what only with the salts. but stay below a few %

pintoshine · Post by **pintoshine** » Thu Jan 31, 2008 7:29 am

do you know of an off the shelf variety of nitric acid? Last time I checked you needed two miles of paper trail and a big permit to buy it. It is the main catalyst for making high explosives after all.

stoker · Post by **stoker** » Thu Jan 31, 2008 7:39 am

here you don't need a permit. it's not very easy to get it, but not that difficult eiter. It's not america here (though the US has some bad influence on our freedom too)
and for most of the nitrations, it's a 99% concentration that is wanted, and that is VERY hard to find.

I've heard of people on this forum who have used nitric acid.

showrguy · Post by **showrguy** » Thu Jan 31, 2008 8:20 am

i just saw a BIG ol copper soup kettle last week in a customers house that looked brand new, i asked him about it, him and his wife started to clean/polish it by hand, after a few days of that they started searching for a better option...
they took it to a guy that kinda sandblasted it, not with sand, but with crushed walnut shells..
it's probably a hundred years old and looks brand new, well, except for some obvious dings and such..

byacey · Post by **byacey** » Thu Jan 31, 2008 10:16 am

The walnut shells is a good idea if all the surfaces are easily accessible.
The ammonium persulfate is an easy chemical to get, available at most industrial chemical supply vendors, as well as any place that sells electronic printed circuit making supplies. The spent solution makes a fine weed and ant killer without being harsh on the environment.

Woody_Woodchuck · Post by **Woody_Woodchuck** » Mon Feb 04, 2008 4:33 am

Howdy,

This all gives me some things to try but I didn’t get around to it last weekend. UNIT 1 (my only transportation) broke down Wednesday afternoon and I spent a couple days getting it up and running. I’m no ace mechanic so it takes me a bit longer than most regular folks. That and waiting for a ride into town for parts.

I couldn’t find ammonium persulfate, only on the web through industrial supply places. I’ll try radio shack?

I like the half lemon with salt scrubber! I’ll try one half cold and the other warmed up in the oven.

Going by Pint's reply I’m not going to try sulfuric acid. I was looking for more of the 'home remedies' anyway.

Besides what I tried already the list of others is:

Ammonia
Ammonia and vinegar
Hydrogen peroxide and muriatic acid. – Although the acid itself did a great job.
Lemon – warm and cold
Lemon and salt – warm and cold
Ammonium persulfate – if I can find some locally.

I’ll try and get to these this week, I have to make up for a couple lost work days and will be doing evenings. Thanks for all the suggestions!

- Woody

byacey · Post by **byacey** » Mon Feb 04, 2008 9:35 am

Have a look here for ammonium persulfate:
http://www.mgchemicals.com/products/410.html" onclick="window.open(this.href);return false;" rel="nofollow

Woody_Woodchuck · Post by **Woody_Woodchuck** » Mon Feb 04, 2008 12:20 pm

It’s not looking good for Ammonium Persulfate. I found one place online that would sell a small quantity (10 grams or 100 grams) rather than 25 kg bags. They stated that a hazardous material handling charge might apply. Something I would rather not have to pay and worry about. If I could find a place around Raleigh, NC to get some, I’d give it a try.

byacey · Post by **byacey** » Mon Feb 04, 2008 1:02 pm

Check around your area and see if you can find a company that fabricates printed circuit boards. You could probably beg borrow or steal 5 lbs of the crystals. This should be more than enough to clean what you have. This stuff when cold doesn't do much to the copper, but once mixed with water and heated to about 120F it will start eating the copper. I don't suspect it would take very long to clean the surface down to virgin copper- maybe 5 minutes or so.

RadicalEd1 · Post by **RadicalEd1** » Tue Feb 05, 2008 7:33 am

FYI- do NOT leave the lemon juice and salt in contact with the copper for more than a few minutes; it will start to corrode your copper and leave it worse off than it was. Admittedly worked great for cleaning off some of the less super strong gook, but when I left it on for a few minutes to work at the stronger stuff I came back to find green grains (read: oxidized copper) growing on my tubing

.

Woody_Woodchuck · Post by **Woody_Woodchuck** » Tue Feb 05, 2008 8:50 am

Howdy. Results are in and pictures attached. This was more to test the cleaning abilities of natural solutions than what acid is stronger. I was curious what old home remedies would do. I’m not opposed to using chemicals when needed but the less I use or have around the homestead, the happier I am. I’m no orgo-veggie (I eat meat!) but I do garden organically so what I raise I’m not scared to eat. (Old Hippie syndrome perhaps?) Anyway… The results did surprise me and here they are:

0000 Steel Wool. Did a fantastic job of removing the oxidation and polished to a mirror finish w/out scratching. It did not get down into the pitted areas. Very time consuming for a major cleanup unless put on a drill or something.
Flour/Vinegar/Salt. Good job of eating away at most of the heavy oxidation. With more soaking and scrubbing it cleaned even the pitted areas. Thinner paste (more vinegar) did better than a ticker paste.
Ketchup. Pretty good job of eating the oxidation. Did not clean into the pitting really well and took more scrubbing than the others. Possibly more soak time or mix with vinegar or salt to help?
Toothpastes. Squat even with scrubbing.
20% Muriatic acid. Damn did this eat away at everything right down to clean copper. Took less than a minute of wiping with a paper towel to eat away the oxidation. With a little toothbrush action it cleaned out the pitting also. Took more effort to wash it off and neutralize than I would like. NOTE: the brighter blue around this spot was there originally not due to the acid.
Vinegar. Ate away the oxidation w/out much scrubbing and left the patina on. Seemed like it would do a good job on light oxidation if you wanted to leave a patina and didn’t want shiny copper.
Lime. So-so. Ate away at some of the oxidation but took some scrubbing. Didn’t get into the pitting too well.
Lime/Salt. Best non-toxic cleaner by far! Ate right down to shiny copper and got into the pitting well. My choice for cleaning the rest of the setup. Only difference between this and the muriatic is it took a little longer soak and some scrubbing but washed off much easier. As RadicalEd just pointed out it did need 15 minutes, took only a couple.
Ammonia. Did alright but not worth the fumes. Changed the patina to a lighter shade.
Ammonia/Vinegar. Much better than plain ammonia. Took some scrubbing and did leave the lighter patina. Again, not worth the fumes as others cleaned better.
Labrador retriever drool. About as you’d expect, crappy. Had to try though as its cheap and plentiful at my place. Can’t be beat for lubricating monofilament when tying fishing knots though!

- Woody

Woody_Woodchuck · Post by **Woody_Woodchuck** » Tue Feb 05, 2008 8:56 am

Pictures should appear now!

Legend to what spots are what:

Pictures of the patches:

junkyard dawg · Post by **junkyard dawg** » Wed Feb 06, 2008 7:18 pm

nothing has ever been easier, cheaper, safer, papertrailless, than hot backset.

new_moonshiner · Post by **new_moonshiner** » Wed Feb 06, 2008 7:26 pm

I second that Dawg, Its just all around hard to beat if one already has access to it ..

doc barleycorn · Post by **doc barleycorn** » Sat Mar 15, 2008 6:09 pm

After making the pans for Pint's copper potstill, I cleaned them with lemon pulp, kosher salt and 0000steel wool. They shine like new. No harsh chemicals necessary. Easily removed the discoloration from annealing.

Pits Rule!!!

pintoshine · Post by **pintoshine** » Sun Mar 16, 2008 4:47 am

I have never told how I clean the pans and the rest of the still because it is a metal workers method and not really suggested for general cleaning.

The 0000 steel wool will clean them with just water but it takes a bit of elbow work.
I mix up warm water and equal amount of muriatic acid. Then I put the pan in it with vinyl gloves on. a little stirring, or not, the black will dissolve instantly to a whitish powder which dissolves completely, and the red oxide dissolves also but takes a bit longer. No elbow work required. Into the sink for a good rinse and I'm done. It leaves the metal a bit dull but it will be nearly perfectly clean, even in the hammer marks.
No cleaning the outside of the finished still to a mirror finish is done in two parts. First is a liberal application of Brasso. This is a magic combination of oxalic acid and ammonia with a thickener of light water soluble oil and 12-0 silica grit. a small amount of rubbing and it will be perfectly clean and shiny. But for the mirror finish, I use a polishing wheel like the ones used to polish jewelery. I use a fine and an extra fine emery stick on the wheel and then polish the copper to a mirror finish. It usually takes two passes. This is a lot of work but the power of the polishing wheel is just amazing.
I completed an 8 gallon rig over the past three weeks. It has some more construction details from questions that have been asked and I will be putting those in my photo album soon.

darel · Post by **darel** » Sun Apr 06, 2008 9:20 am

I use lemon juice personally. If a piece is small enough, I'll drop the whole thing in and let it soak for 18 hours. If a piece is large, such as cleaning a 2 inch copper pipe, than I soak a paper towel in the juice and wrap it over the pipe and wrap saran wrap over that to keep eveything form getting wet and drying the lemon juice off the pipe leaving towel mark impressions on your new clean copper. This is the cheapest and easiest way to clean copper. I buy bulk at costco or the biggest bottle at safeway.

Home Distiller

Cleaning copper – Results and pictures are IN !!!

Cleaning copper – Results and pictures are IN !!!

RESULTS ARE IN!!!

Pictures

Brasso!