Remove Galvanized Coating with Vinegar

You can strip galvanized coating off steel using regular household vinegar. I saw a video that used muriatic acid and another that used citric acid. Muriatic acid only took a few minutes of bubbling and smoking to clean the metal, but it required rubber gloves, eye protection and a respirator. The citric acid took several minutes long with less bubbling and less protective equipment required. 

But I don't have either of those substances, so I wanted to see if I could use a weaker acid like vinegar to accomplish the same thing.

It worked. It took several hours instead of mere minutes, but it did work. Household vinegar removed all the galvanized coating off washers, nuts and screws down to the bare metal. And more importantly, I didn't have to wear rubber gloves or a respirator to use it.

You can see the bare metal at the bottom of the washer. The top is still galvanized. All I did was submerge half the washer in regular 5% household vinegar for a few hours. This is a simple and safe way of making galvanized metal safe to weld and sand.

I already use vinegar for a lot of things, so I usually have a couple of gallons on hand. I use it as a weed killer, glass cleaner and rust remover. I use it to etch copper for my craft projects, and I've even made a circuit board by etching with vinegar.

Why Would You Remove the Galvanization?

Metal gets galvanized to protect it and prevent it from rusting, so why would you ever want to remove it? Well, the galvanized coating emits toxic fumes when it gets heated and throws off toxic dust when sanded. 

This is really dangerous if you want to weld the metal or even heat it with a torch for bending. Sanding the coating creates fine particles that you can breath in, so that's not very helpful either. The same goes for etching and shaping galvanized metals with a rotary tool.

Let me repeat: Welding galvanized metal can make you sick, heating it with a torch to bend it can make you sick, breathing the dust from sanding or carving it can make you sick. That's why using a chemical removal process with vinegar seemed so much better.

Yet so many people still use washers and nuts and bolts in their projects, I knew there had to be a simple way of stripping the coating from metal. You know the types of projects I'm talking about. Check Pinterest for "welded art" and notice that they have all removed the galvanized coating before they started welding. 

My welded washer bowl project would have been much safer to do if I had known this.

I made a welded washer bowl. Unfortunately, I didn't know how to strip the galvanized coating yet, so I probably poisoned myself in the process.

Results With 5%  Household Vinegar

It is slow. It takes at least a couple of hours. I had to leave the metal submerged in the vinegar all day or even overnight for some of the heavily coated items. But eventually, all the coating was gone. As with any chemical etching process, periodically agitating the container, stirring, and making sure bubbles don't form around the metal can all help speed the process and assure consistent results.

I wasn't in a hurry, so tossing some washers into the vinegar in the morning and coming back to the clean version that afternoon was just fine with me. But if I was on a schedule or needed a part quickly, I might have to find a better solution. Luckily, there are more concentrated vinegars that can do the job much more quickly but still just as safely.

Stronger Vinegars

Normal grocery-store vinegar is usually diluted with water to 4-5% strength. Sometimes you can find a bottle of 10% vinegar at the grocery store. However, you can get 20%, 30%, 40%, 45% and even a claimed 75% strength. Sometimes these can be found at hardware stores being sold as "all natural" weed killer or rust remover. They are more expensive than standard vinegars, but they are also 5-10x stronger and will remove the galvanization much faster, so the price is probably worth it.

It looks like there isn't much of a price difference between 20% and 45%, so the 45% is probably the best choice, (affiliate link) or at least the most economical. 

Or just search for "strong vinegar" to see a wide selection of strengths and sizes. (affiliate links). 

Forget Vinegar, I Want the Strong Stuff

So vinegar isn't strong enough? Fine, buy the strong stuff, Muriatic Acid (affiliate link) is the chemical in concrete cleaner/etcher solutions. It's even used to balance the Ph in swimming pools. Just be sure to use all the precautions and safety equipment.

Citric Acid (affiliate link) is the stuff they use to make food taste tart. Lemonade powders, pudding and gelatin mixes, all probably contain citric acid. So this is also a fairly safe and "natural" option.

Why Not Just Buy Uncoated Metal?

If you have access to a metal shop, one that caters to professional welder and metal workers, you can probably find uncoated metal. But most hardware stores only carry coated metal. Try to find an uncoated washer, screw, bolt or screw in your local big box store. I looked at several and couldn't find any.

Amazon does have some plain black washers (affiliate link) without a galvanized coating. But after reading about them I remembered some things from my childhood (back when galvanized was not standard). The washers come packed in a nasty grease, in a goopy mess inside a plastic bag inside a oil-stained, wax-coated box. You have to clean the washers with some kind of nasty solvent before you can safely weld, torch or sand them. So it's really no better than stripping the galvanized coating with vinegar.

Conclusion

If you are going to be doing any arts and crafts with washer, bolts or screw, then you need to get yourself some strong vinegar and plan ahead for letting them soak for a few hours. It's inconvenient, but safer for you and your family when you fire up your welder, torch or rotary tool. And you can use the same bottle of vinegar for other projects. You can use the same vinegar as weed control, wash your windows with it, or etch copper and PCBs. You can even dilute it with water to make regular strength household vinegar for use in food prep. So for me, vinegar really is the best and most versatile option.

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