- 1 What is pickle and pickling?
- 2 How to Heat Pickle
- 3 Notes on Pickling
- 4 Types of Pickle
- 4.0.1 Sulfuric Acid Pickle
- 4.0.2 Citric Acid Pickle – a safe and non-toxic pickle
- 4.0.3 Suppliers of Citric Pickle or Citric Acid
- 4.0.4 Salt and Vinegar Pickle – Another safe and non-toxic pickle
- 4.0.5 Alum Pickle
- 4.0.6 Alum, Vinegar and Salt Pickle
- 4.0.7 Sodium Bisulfate Pickle
- 5 How To Remove Copper Plating or “Help, I Pickled My Silver Jewelry and Now It’s Covered with Copper”
- 6 Maintaining your Pickle
- 7 Information on Copper in Waste Water
- 8 Neutralizing Pickle
- 9 Non-USA Suppliers of Pickle
What is pickle and pickling?
Oxidation on copper made by heating with a torch.
Pickling is a process that removes oxidation and flux residues that develop during the soldering process. Pickles are (usually) a mixture of an acid or an acid salt and water that removes oxides and flux residues from metal. See my article: Soldering 101 – Oxidation, Flux and Fire Scale Prevention for more information. Pickle does not remove firescale or firestain. The only way to remove firescale is with abrasives.
Because of the corrosive nature of acids and acid salts, the handling and use of pickle requires specific safety precautions. Of course, the amount and degree of safety precautions vary depending on the type of pickle. There are certain pickles, like vinegar or citric acid pickle, that are much less dangerous than say, sodium bisulfate or sulfuric acid pickle.
Baking Soda (Sodium Bicarbonate) is commonly used by jewelers as a neutralizer. Sodium Bicarbonate is a base. A base plus an acid equals neutralized. (Remember those science classes? See Chem4Kids.com for more in-depth info on acids and bases).
After pickling your metal, you need to neutralize the acid – even if your pickle is made from vinegar or citric acid – with a base. If you don’t, the acid will continue to eat away at the metal. So, once you’ve removed your piece from the pickle, dunk it in a Pyrex or other type of oven proof bowl containing a mixture of baking soda (a small handful) and (a few cups) water. There is no exact recipe. You’ll know it is working if your piece bubbles when you place it in the neutralizing solution.
It is best to simmer or boil jewelry in the neutralizing bath but just hot pickle will work. Clean with soap and water and rinse well. Simmering or boiling in pickle is especially important to do, if there are enclosed areas, like when pickling a hollow formed ring, or a two part dome. Boiling helps the pickle to reach deep into enclosed spaces; spaces that may only accessible through small openings. Don’t boil neutralizer in a pot you will cook in. Get a used one from the junk store and designate it for studio use only. Before boiling in baking soda make sure that any stones or materials, used in the construction of your piece of jewelry, will survive at or above 212°F.
How to Heat Pickle
Since most pickles work best when warm, you need something to keep it warm in. Most jewelers use a ceramic lined crock pot or a commercially available pickle pot. Use the lowest setting. Remember: You don’t want the pickle boiling.
It’s important to only use a pickle pot with a ceramic liner as the acid will slowly eat away at any metal.
Try to avoid tops with steel screws (this is a tough one!)
I get all of my pickle pots from resale shops and garage sales. Check for cracks in the ceramic before you purchase them. They usually cost anywhere from $5.00 to $15.00 US – depending on your area and the size of the pot.
In a pinch, you can use a coffee cup warmer and a heatproof glass jar as your pickling system. You can also use the coffee cup warmer for drying metal clay pieces.
Notes on Pickling
- Always use Distilled Water to make your pickle with. The minerals and metals in your water will react with the acid.
- You don’t need separate pickle pots for silver and brass, copper, bronze. The pickle becomes spent a hair quicker but, pickle is cheap. If it’s because you want to avoid the free floating copper, don’t worry. See below for a simple, quick fix for copper plating. One last reason to not have two pickle pots: Counter space – who needs their counter space taken up with two pickle pots.
- All pickles work best when warm. Don’t boil.
- When mixing up a new batch of pickle, remember to add the dry acid to the water. Don’t dump the water into the acid. Want to know why? Read this. Of course, when the water evaporates, you’ll need to add more water. You can do this because you aren’t dealing with a bunch of concentrated acid. The acid is already dispersed in the water.
- For all types of pickle when mixing: Wear a good mask – I like 3M’s particulate mask, gloves and safety goggles. Have good ventilation. Even if wearing a particulate mask, keep your face away from the pickle pot. Wash hands well after mixing and using. Safety, safety please!
- Pickle strength can be adjusted. You can add more or (as in my case) less than the instructions state. I always use about 1/2 of what is recommended and it works fine. It all depends on how fast you want your pickle to work. I find the “pickling break”, maybe 5 minutes, to be time used for other facets of the project. Time to hammer the wires or get those jump rings made.
- After using tongs/spoons/measuring cups to handle dry or wet pickle, neutralize them with baking soda and then…
- Don’t forget to rinse the baking soda off of your spoons/tongs before putting them back in the acid. Over time, un-rinsed, baking soda coated tongs – repeatedly dunked in pickle – will neutralize your pickle.
- Never again use the spoons, tongs or measuring cups for cooking! Label them “for studio use only”.
- Don’t forget to turn off the pickle pot before leaving the studio for the night (or day). I had my pickle pot on a power strip that was attached to my fluorescent light. When I turned off the light, the pickle pot went off too. BUT, I got into the habit of turning off the pot before turning off the lights. One of my only good habits!
- Don’t put steel into the pickle pot unless it is stainless steel. Stainless is safe in pickle. Remove all binding wire before pickling – unless you are using copper or stainless steel wire. Regular steel binding wire, when dropped into pickle that has free floating copper molecules, will create an electrical current that plates all surrounding metal with copper. Sometimes, this is something that you want to do but, most of the time it isn’t. IF this happens to you – Don’t Panic. It’s very easy to remove.
- If you do put steel into the pickle, just take out the offending material. The pickle will be fine. You don’t need to throw it away.
- Sometimes, if I leave silver pieces in my (sodium bisulfate) pickle pot for too long, a silver matte, gray, “something” coats the silver. I’ve left pieces in for an hour or less and had this happen. I then must re-torch and re-pickle (sometimes twice) to remove the gray gunk (while the exhaust fan was on high). Anyone else ever had this happen? Does anyone know what is going on here? I cannot find ANY information on this problem.
Types of Pickle
Sulfuric Acid Pickle
Some pickles, although not very common today, due to the dangerous nature of the acid, are made from a solution of between 5% and 10% sulfuric acid. They are now difficult to find and are usually seen in the manufacturing arm of the industry.
Citric Acid Pickle – a safe and non-toxic pickle
- Citric Acid (anhydrous fine granular citric acid – MSDS) is the new, “green” pickle but, there are a few disadvantages:
- It doesn’t last as long as the SB. Actually, it has a lot less longevity than traditional pickle.
- It can grow mold – if it sits cold too long. Heat it up a few times a week. It does get moldy. Mine sat for a few weeks and created a cloud-like mold. But, the mold was easily removable. I think the mold can be avoided with frequent use.
- And because of the mold, can smell funky – although, I never noticed a weird smell.
- It is not as quick as Sodium Bisulfate pickle
- The higher the temperature, the better it works which can result in burns.
- You still can’t pour it down the drain if there are copper particles present. If it is used only with fine silver, no problem but, sterling, German silver, Argentium, most golds, brass, bronze and copper are going to shed a few copper molecules. You generally don’t need to pickle fine silver and 24K gold.
- A safer, non-toxic pickle (don’t inhale it!). Add more citric acid as the solution weakens or make new.
Recipe for Citric Acid Pickle:
One part citric acid to 6 to 7 parts distilled water.
Another Recipe for Citric Acid Pickle:
1 cup hot lemon juice with 1 teaspoon of salt or 1 cup of hot vinegar and 1 teaspoon of salt. Ronda states, in the post, that this works well with Argentium silver.
Add Citric Acid to the water – Important
Suppliers of Citric Pickle or Citric Acid
All prices as of 8/2014
- Amazon USA – Spicy World – 5 lbs, $15.98
- Bulk Foods – 5 lbs, $16.56
- Contenti – 2 lbs, $10.65
- Ethical Metalsmiths: Black Magic Biodegradable Citric Pickle. $13.95, powdered form – makes one gallon.
- FDJ On Time: Citric Acid – Eco Friendly Pickle – 1 lb, $6.95
- Otto Frei: Citric Pickle – 2 lbs, $5.95, makes one gallon
- Soap Goods – 6 lbs $20.51
- Local Pharmacies, Wine and Beer making suppliers.
Another type of Citric Acid Pickle
***Note: Citric Acid can cause digestive and respiratory tract irritation. Causes severe eye irritation and may cause skin sensitization by skin contact. Have I said mask, eye protection and gloves when mixing? Eye protection when using?
Salt and Vinegar Pickle – Another safe and non-toxic pickle
Salt and Vinegar Pickle Recipe:
- Add one teaspoon of salt for every cup of vinegar. I’d use distilled white vinegar so that you can see what’s in the pickle. Works much faster when warm.
The recipe, from what I can discern from the web is: put in a big clump (handful?) of Food grade Alum aka: Aluminum Alum into the water in your pickle pot. Stir. Works much faster when warm.
Alum can be found at the grocery store (in small quantities for more money), Amazon carries the Barry Farm Brand for $8.53 US a pound or buy direct from the Barry Farm. I can’t find anymore suppliers. Maybe someone else knows? It shouldn’t have iron in it BTW. There are many different types out there.
Alum, in its various forms is used in pickling (food grade), fixing dye to fabric, baking powder, dying and tanning hides and fire extinguishers, to name a few uses. Per McCormick (the Spice People) “It is a general purpose food additive that functions as a firming agent.”
Alum, Vinegar and Salt Pickle
One tablespoon of alum into 1/4 cup of distilled water. Dissolve. Use 8 parts white distilled vinegar for every tablespoon of salt. Pour the water and alum into the vinegar. Heat to simmering (pickle pot on high) and then add salt to the mixture. Turn down temperature an keep warm in your pickle pot.
Sodium Bisulfate Pickle
The most common pickle for jewelry making is composed of sodium bisulfate (MSDS on Rio Pickle). Sodium bisulfate is also used as a ph reducer for spas so, you can purchase a product like: In The Swim ph Reducer to use as your pickle. The “Swim ph Reducer”, for a 6 lb bucket, costs $22.99 at Amazon. The Rio Pickle works out to a little less (it’s $11.25 for 3 lbs = $22.50 for 6 lbs). Swim Time 6 lbs ph Reducer at Wally World (Walmart) sells it for $13.82 (as of 8/14). Check to be sure the label says: Sodium Bisulfate.
Different names for sodium bisulfate pickle:
***Note Sparex #1 is for pickling iron and steel.
ph Reducer – Sodium Bisulfate Pickle
Mix, approximately, one cup of ph reducer to a gallon of distilled water (Acid to water). Adjust amounts for your pickle pot’s size. You can determine how much it holds (if you don’t buy new and have that info readily available). Using a measuring cup, fill the pot to within one or two inches from the top with water. Record your results for future reference. (You don’t want the pickle overflowing when you put items in it!). So, don’t overfill.
*Note: there are 4 quarts in a gallon, so the ratio (don’t know if this is truly accurate as one is liquid and the other dry) for a quart would be: 1/4 cup of ph reducer per quart of distilled water. Fill to within 1-2 inches and then add ph reducer.
How to mix Sodium Bisulfate (aka: Sparex #2, Rio Pickle, Safety Pickle)
- Use only distilled water
- Determine acid to water ratio from packaging.
- Measure water and pour into pickle pot.
- Either have two studio dedicated measuring cups or wipe dry the one you just used.
- Measure out your pickle.
- Slowly pour the powdered pickle into the water in the pickle pot.
- Turn on pickle pot/crock pot. Set it on low.
- Stir with your copper, brass or plastic tongs or a jewelry dedicated plastic or wooden spoon.
- If you can’t wait anymore and there is still some of the bisulfate salts on the bottom, go ahead and use the pickle anyway. The pickle will work and the remaining powder will eventually dissolve.
Warning: (This from Rio Grande’s site: “Sodium Bisulfate. Releases Sulfuric Acid, (here’s SciLab.com’s MSDS on Sulfuric Acid) on contact with water. Causes burns and irritation. Avoid contact with eyes, skin, and clothing. Do not inhale dust. Do not swallow. Keep out of reach of children.”
Suppliers of Sodium Bisulfate Pickle
- Contenti: Sparex #2
- Kernowcraft: Safety Pickle (UK)
- Otto Frei: Pickle-Ottotech
- Rio Grande – Rio Pickle
There are many more suppliers: Just Google “pickle for metalsmiths or jewelers”!
How To Remove Copper Plating or “Help, I Pickled My Silver Jewelry and Now It’s Covered with Copper”
I use plastic, 16 oz., disposable medicine cups for this job. Using the clear, disposable measuring cup allows me to see how much of each chemical I am pouring in.
First and rather obviously: remove from the pickle, neutralize and rinse the offending piece of metal. Next, read the following instructions for removing copper flashing.
- The mixture consists of 50% regular ‘ole, drugstore variety hydrogen peroxide (available in 3.5% – 6% concentrations) and 50% pickle from your pickle pot. Here’s an interesting list of the different concentrations and uses of hydrogen peroxide by Daniel Carter. Who knew, (well, maybe you did), that it is also used as a rocket fuel? (90% concentration). To learn more about hydrogen peroxide (you’ll might be surprised at its uses and how it works), please see the For Additional Research section of this article.
- Insert copper plated piece into the mixture.
- Wait a minute or two.
- Put panic attack away for now.
The pickle/peroxide mix can be reused. After a few hours (I leave mine to sit over night) the hydrogen peroxide will no longer be active.
Maintaining your Pickle
If you use sterling silver, copper, brass, many golds – including gold plate – or bronze, your pickle will eventually turn a turquoise-y green. Your blue/green pickle has molecules of copper swimming around in it, just waiting for some steel to show up.
Pickle lasts a long time but, over time, it will become dirty with dissolved dirt, metals and cat fur. With just a little maintenance, your pickle can live a long and purposeful life.
When the pickle becomes slow, add more acid, if the pickle evaporates add more distilled water.
Keeping your pickle free of gunk, will help to extend its life. I use a (jewelry dedicated) Melitta Coffee cone and cone filters to strain the pickle and remove unwanted materials. It helps if your filters fit your cone.
Another way to extend the life of your pickle is to remove copper from the solution (if present). Ethical Metalsmiths employs steel wool to “soak up” the copper ions. The steel wool is then recycled. Read their article to learn more.
My copper removal test
I decided to try out Ethical Metalsmith’s steel wool idea and the following is what I experienced:
- I put a handfull of steel wool into a small, plastic measuring cup with holes punched into the base and sides.
- A few minutes later, I opened the top to check on it and my studio was filled with a horrible stench – don’t know what the byproduct of copper, steel wool and sodium bisulfite is (I did research it!) – but, the smell drove me outside. Perhaps, I should have done it outside, in the first place!
- (Image: after pickle (L), before pickle (R). The pickle “ate” the steel wool. While the steel wool was coated with a lot of copper, the odor was so nerve wracking that I deemed the experiment worthy of further research.
- Does anyone know the name of the (off-putting) fumes that I created? Would love to hear your explanation. I’m guessing oxygen and…?
Yet one more idea for disposal of cupric/copper sulfate at Finishing.com
Here’s a video on copper disposal from John Smith on Youtube.
Information on Copper in Waste Water
Copper can cause problems in waste water, for aquatic life, drinking water and more. Copper (copper sulfate) is most damaging in a liquid state, as opposed to in its solid form. It can be hazardous in a septic or water treatment system as it can destroy the beneficial bacteria used in processing our drinking water. The same is true for your septic system plus, there’s the hazard of runoff to one of the many bodies of water listed below (I am an obsessive person). Don’t dump your copper saturated water (please read this article by AquaticBiologists Inc.) or pickle into street drains, sewers, lakes, streams, brooks, cricks, brooklets, braces, aqueducts, pools, swimming pools, kiddie pools, reservoirs, lochs, mill ponds, sluices, tarns, firths, canals, oceans, inland seas, basins, water towers, holding tanks, puddles, the high seas, the 7 seas, narrows, Davy Jone’s Locker, sounds, straits, coves, gulfs, fjords, sounds, inlets, everglades, bogs, tributaries, creeks, rivulets, runnels, marshes, swamps, springs, sink holes, bayous, bays, harbors, estuaries, channels, lagunas, lagoons, or your bath water, etc. for gawds sake! Dispose of your pickle in an earth-friendly, ethical fashion. Please.
Before disposing of your pickle you should neutralize it. This is done by adding a base (generally baking soda) to the pickle. My recommended steps are as follows:
- Wear protective gloves and a face mask or goggles.
- In a large (preferably) plastic bin, bucket, tank, sink – large enough to completely hold your pickle pot in and the container you are pouring the used pickle into. Of course, in my description of how I just changed my pickle, I did all this in my stainless steel kitchen sink. Bad dog.
- You might want to have a bowl (jewelry only)handy, filled with a water and baking soda solution (a couple of cups of water to a small handfull of baking soda), for spills and neutralizing the filters. See #4.
- Using either a funnel or a Melitta and a Melitta filter, filter out any waste products from the pickle.
- Fold the filter over, to seal in the debris, and dip in the neutralizing bath. Throw away.
- You may want to do this outside. Remember that homemade volcano project with vinegar and baking soda? Well, pickle and baking soda do the same thing. I used to neutralize, right in my pickle pot but, it always bubbled over the top and got everywhere. But, I have learned (yes, I have) that, if you neutralize your pickle in a large container, it doesn’t bubble all over the place. The 2.5 gallon water jug worked great for me. I am much happier now that I’ve discovered this fact!
- If you are taking the liquid, neutralized pickle to the hazardous waste store (ahem), or are storing it for a while, ensure that your container has a plastic – not metal – lid. Metal lids will be eaten by the pickle.
- Label the container as poisonous and it wouldn’t be a bad idea to write what is in the container. I like to draw a skull and crossbones on the container too! Drawing practice and safety practice, all in one fun exercise. (I need to get out of the studio more often!)
- Keep the top off until it is fully neutralized – let it sit for a bunch of hours. Because, the gases that are being released will build up and possible blow. Not good.
- Figure out your method of disposal: evaporation, leaving it in its liquid state or removing the copper ions with steel wool.
- Contact your local waste management company for their requirements and practices.
- Store evaporating pickle away from all living things – especially: animals and children. Keep the entire mess away from nature in general.
My recent Pickle Changing Experience
I just replaced my, almost 1 year old pickle. I took photos of some of the processes I went through. Mind you, I’ve done this a whole heck of a lot of times but, this is my first “documented” pickle change-out. Thought I’d share.
My murky, filthy but, still working pickle. I changed it because I was getting a silvery coating on all the copper that I pickled. My suspicion is that it was free-floating zinc, no doubt present, because of a couple of pieces of brass that were left in the pickle a wee bit too long. I’m going to record the date, of the pickle change, so that I’ll have an official record: 8/10/15 (I think). It’ll be interesting to see when I’ll next be changing the pickle (at least to me).
Working with cold pickle, I strained out the goop that was in the bottom of the pot. I used a Melitta and Melitta filters. I went through six, or so, filters because they became clogged with debris and didn’t drain fast enough for my busy self. Here’s a shot of one of the filters:
The entire procedure was done in my kitchen sink. I rinsed and scrubbed the sink and counters after the pour because I didn’t want to poison anyone, nor did I want the acid to eat away at my sink or counters. Prior to all this, I moved all sponges, dishes and foods so that there was nothing nearby to contaminate with pickle. I would prefer to do perform the pickle changing in a laundry sink but, alas, I don’t have one.
I used a 2.5 gallon, plastic water jug. I cut a tab in the top to accomodate the Melitta and, to allow air to enter the container, later. My method of disposal will be evaporation and recycling of the crystalized copper. So, air circulation is essential.
I mixed the baking soda in a 2 cup measuring cup – a few tablespoons to the 2 cups of water. I slowly poured the mixture into the pickle, allowing it to be neutralized in small doses. I mixed up another 2 cups of neutralizer and slowly added that too. It took me about 20 minutes to fully neutralize the pickle. You can tell when it’s done: if you add baking soda and it doesn’t bubble, it’s neutralized.
I’m now cooking up a batch of citric acid pickle to see if I like it or not. I’ll let you know what I think. Back to Table of Contents
For additional Research
- American Elements: Copper Sulfate CuSO4
- Art Jewelry Magazine: 12 Greener Chemicals for Your Studio by Addie Kidd. Kalbach Publishing. Found under ArtJewelrymag.com/reference. Web. 2009.
- Britannia.com. Hydrogen Peroxide: Chemical Compound. Written by the Editors of Encyclopaedia Britannica. Web. Date unknown.
- Copper.org for information on copper, copper sulfate and other copper related information.
- Educate-Yourself.org. Articles on Hydrogen Peroxide. Compiled by Ken Adachi. Web. Date unknown.
- Ethical Metalsmiths.org. Quote from their site: “Mission: Lead jewelers and consumers in becoming informed activists for responsible mining, sustainable economic development and verified, ethical sources of materials used in making jewelry.”
- Ganoksin: Pickling Notes by Charles Lewton-Brain. Web. 2007.
- Hoover and Strong: Pickle: Cleaning up after Soldering by Sara M. Sanford, Web. January 1, 2008.
- Myfunhealthylife.hubpages.com. Food Grade Hydrogen Peroxide and its Uses. Daniel Carter. Web. 7/18/13.
- Northstar Chemical – Sodium Bisulfate 25%. Web. 2013.
Non-USA Suppliers of Pickle
Suppliers for European, Asian, African, Australian (and many, many others) locations, please see my webpage: Suppliers Outside the USA.