Neumonic from my ag teacher,

Do like ya otter
add acid ta watter

Gene Olson
Sculptor
Elk River, MN

acid etch removal of oxides.

Gene Olson
Sculptor
Elk River, MN

but can you tell me how long you should leave it pickling

Rick,

I once asked my father, a research chemist, this question and the answer was too abstruse for me to fully understand. Not much surprise there. :-)

In short though, acidic pickling solutions are reducing agents. That is, they remove the oxides of the metal by combining with them to either change them to something that stays in solution or to strip the oxygen molecules from them and turn them back to their original unoxidized form. Or something like that. Like I said, too complex for me to really grasp. They gobble up oxides faster than they gobble up the un-oxidized metal.

10% sulfuric acid is one pickle formula. Sodium bisulfite is, if I remember correctly, sulfuric acid that is half-neutralized so it is safer to use and less aggressive. The half neutralizing also buffers it so it is less quick to deteriorate with use, I think. Hazy recollections of answers given thirty years ago when I asked Pop.

So, if I am figuring this correctly, it cleans and protects by changing the surfaced to something that will not rust (oxidize) as easily. Right? Or, does it just clean? I have used pickled and oiled cold rolled steel before in the shop I work for, but was never sure what that really meant.

Rick Crawford at Smoky Forge

just cleans. reheat........NEW oxides :)

The pool Ph works very well. That is what I used for the pickle on the copper roses I make. I picked up a jar of it at Meijers in the pool supply section cheap and local.

Tim

I myself use the sulfuric acid (battery acid). Little jug from the autoparts stores for $4 and makes two gallons.

The reasons I use the sulfuric acid because even when it is cold outside still works well. Then if a larger piece I mix it up in a squirt bottle to clean the piece after all of the welding and heating.

Wife complains about all of the holes in my clothes.

warren
http://www.flickr.com/photos/metal_recipes/

What is the ratio of sodium bisulfate to water used for pickling?

I use about a cup or so of sodium bisulfate in 4 gallons of water. If it seems to pickle a bit too slow I will just add more. I mix mine in a 5 gallon plastic bucket.

Fred

Fred Zweig
Metalsmith

Mostly the uses are for removing the oxides that mess up your soldering or welding joints. You use Pickle after heating for the same reason you use flux before heating...to keep the O2 away from your work spot and building up crusties, nasties and non-workable and non-stickable attachments. Be sure that no matter what you use you have good ventilation. Wash your project in clean water after pickle and dry thoroughly before moving on. If you are welding and such you should also be cleaning your joint by sanding or grinding as appropriate for your joint before adding the flux (except in instances were you are using materials such as flux-rod, gas-wire feed and such when oxides will not build up in front of your weld. Us old cranks weld some, smack off the crap some, weld some more and smack it some more...of course we gas weld without glasses half the time for convenience and will all have cateracts by the time we're 55 also....good luck, be safe.

thanks for asking the questions i was was too shy to ask.

charley

If you have used flux and silver soldered copper, silver, brass, or gold, the pickle removes both the oxides on the surface of the metal and also the borax glass which the flux has formed.

marilyn

Jake,

Muriatic acid or vinegar will remove mill scale just fine.

Hey Jason,

I work in sterling silver, and know of this charge, but have never tried sticking steel in the pickle. I just know to not use "the wrong tongs," to place and remove my pieces from the pickle pot 'cause of this change. Is this reaction something that can be seen, and is it an instantaneous reaction?

I do have lots of steel left over from when I was creating more sculptured pieces and welding. I love the look of copper, but it gets sooooooo soft after brazing, and needs
to be work hardened, so this coating sounds like a great idea to play with.

Do you have anything that you have done to share? If you do please post it...I'd love to see!

Cheers,

Jamie Santellano

jamie,

  yes it's pretty much instantaneous and really exciting if you're touching the metal on the sink when you dip your steel. nasty little shock there. i don't exactly know how to post pix but if you send me an e-mail at my website i can fire back an attached image of a little copper plated fellow i made. the object was plated and then sandblasted several time before i got exactly what i wanted. 

keep in mind with doing this that it's just a very thin layer of copper that sticks and can be rubbed off with a green scrubby pad.

hang your object on a steel wire and dip it in your pickle while wearing gloves. the copper ions will stick to any metal surface in the pot so don't do it while you're cleaning your silver pieces. that's about as much advice as i can offer.

 jason

hutchersonsculpture.com

copper coated idol: this is not exactly the best image but it gets the idea across. the object was a gift and i had to shoot the photo on the fly so i would have any sort of documentation.

Jason,
Well when my pickle gets dirty it gets a nice blue color. Mostly used for copper but about the same color with sterling silver. What I do about every 6 to 8 months make another batch of pickle.
(See above I use the sulfuric acid).
I use these Rubbermade tubs, and around that time they are also pretty much beat up. I set the old batch of pickle outside with the lid and let it evaporate. Now I have this nice sludge of copper sulfate. Rub that on some steel and it plates with the copper. One of these days I might do something with it, I haven't made anything with steel that I want to copper plate lately, rather just make from copper.

I also have a couple pairs of pliers that get dipped into the pickle and they are now copper plated, no shock.

Here is my pickle station. The tubs are on griddles because they get a little frozen in the winter.
Looks like it is about do for a change.
Pickle station
warren
http://www.metalrecipes.com

warren,
that blue is a pretty color. have you tried using a ceramic crockpot for your pickle?

myself i don't use much copper other than sheet for making lamp shades. it has gotten too expensive to buy as scrap and my work uses almost exclusively found material (i'm cheap!)

any suggestions for a soft oxidizer? something i can spray on steel that won't burn me and is fairly non- toxic. i normally just leave stuff outdoors but what with the summer droughts it might take a month just to get a decent coat of rust going.

thanks, jason

Jason,
I have never tried using a crock pot. When I first started working with copper I learned (30 some years ago)to use the sulfuric acid. At the time the guy showing how to use had a lead tub. To all of my searches I could not come up with a lead tub and pricing the lead sheet was out of my budget. Knowing that sulfuric acid was the same as battery acid, I thought heck batteries are made from plastics. At first I used the 5 gal plastic bucket. It was too small for most of my work. I switched over to the Rubbermaid tubs a long time ago and I found they always worked the best. (note one of them in the pic is for quenching after annealing) Sometimes I will have four or five pieces in their at one time. I also have a much larger tub that I set larger pieces in and then squirt the pickle on with a hand sprayer. Crock pot this size would be hard to come by and I really do not see why you would want one.

If you are looking to rust steel couple of options. One is to get some ferric nitrate (search this site and you will come up with suppliers and its use) or you can make a hydrogen peroxide and salt solution.

warren
http://www.metalrecipes.com

Hi Warren,

More on the crock pot...It works REALLY well! I have a small one and a larger one that I keep heated most of the day while I'm working in the studio. The warmer the pickle the (NOT BOILING) the better it works. I have drilled a hole in the top of the plastic lids for ventilation, so that the pickle doesn't get overheated. I use the Sparex granules with water.

I've heard of others using a turkey fryer for pickle pots as well, although I've never used one. The Jewelry Company that I assemble Jewelry for as an Independent Contractor uses this same method.

My teacher in Ireland has a Large pickle pot as well. He has a tub made of a hard plastic (not sure what kind) with a heater for an aquarium in his. It is brilliant! Give it a go sometime, and let us know what you think...

Cheers,

Jamie Santellano

Jamie,
Yes people tell me how well a crock pot works and to use the PH down or Sparex. Most folks that recommend that process are doing jewelry size work.
But see my problem is that I am not in the studio all of the time. And when in there it might only be a couple of hours after my day job. So having to heat the pickle to work better is a bother. With the sulfuric acid even when the water is about frozen it still works.

Also try finding a crock pot where you can put in a disc of copper that is 16 inch in diameter.

Only time I turn on the griddles is when the pickle is frozen and works faster than a aquarium heater. I have tried one of those before. The griddle has sand on top to keep from melting the plastic tub. The griddle was five bucks from the Salvation Army store. Also the griddle has temperature settings so I can set at 120 degrees if needed.
warren
http://www.metalrecipes.com