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Stripping zinc with vinegar


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One thing I haven't seen mentioned elsewhere (although I'm sure I just missed it) is that many hardware stores sell "horticultural vinegar" for use as a weed killer*; it's a lot stronger than regular white vinegar. Seems a good middle ground between regular vinegar and muriatic acid.



*Don't do it. Vinegar only kills the leaves, not the roots, and it's horrible for the soil bacteria.

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  • 3 months later...
On 10/7/2009 at 9:31 PM, pkrankow said:

Yep, its that easy. When I need to next I am going to take a 5 gallon bucket and add 2-3 gallons of vinegar to it. Something to prevent aerosol vinegar from choking, such as a towel cover, is necessary. I would put the lid on top of the towel, but not lock it down the hydrogen gas needs an exit.

Vinegar also removes rust effectively, and that is likely my next use since I have a pile of small scrap sheet metal from barrel hoops I'm going to try cleaning and pile welding.

Phil

Phil. I use a lot of vinegar to remove rust and such. If you want speed it up ( or dissolve latex paint) grab a cheap crock pot on low temp. Greatly decreases time.  OOPS, forgot to mention do it outside. Can really get nasty.

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  • 4 months later...

Former chemist, here.

pkrankow- I imagine you got a lungful of vinegar vapor with a little zinc acetate particulate. I could see that there would be a vapor plume that you would walk into if the jug was near the door that you entered the garage by. But, such a strong personal reaction would be unusual; I'm guessing you are sensitive to it or there was some other leftover material in the bucket. The chemical reaction is not a vigorous one. On the plus side, you were probably protected from catching a cold for a couple of days.

Hydrogen is produced by the hydrochloric acid (muriatic) attacking the metal and leaving H+ ions and metal chloride left over. The H+ (and some spare electrons from the reaction) get together to form H2, hydrogen gas.

SAFETY TIP: Always pour acid into water, not the other way around. Diluting acid produces a surprising amount of heat, enough to boil water. If you pour the water into the acid it may micro-boil and thus spatter acid around. Whenever I need to greatly dilute concentrated sulfuric or hydrochloric acid I consider pouring it over ice.

Re: horticultural vinegar- never heard of it before, great news! Nothing controls horsetails like vinegar.

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Hydrogen molecules are very light and small so they tend to ventilate very quickly. A mixture of hydrogen and air(oxygen) is indeed very easily ignited and will detonate rather than burn so it  creates a bang like a shot. The Swedish name for the mixture is 'knallgas' which translates into 'bang-gas' The amount generated from stripping zink plating is however very small and the amount of hydrogen in air is (due to the low density) small thus the energy released in the bang is small. Thus, even if it does ignite, it is very unlikely to cause any damage even if the sound may make someone believe you are firing a handgun.

Any danger is more likely to be caused by the aerosols described above.

Propane, acetylene and similar gases are much heavier at atmospheric pressureand and do not migrate as quickly and thus very much liklier to cause danger if ignited.    

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  • 5 years later...

I've stripped zinc off galvanized metal with vinegar. Now I have a sludge of zinc, rust and a tiny bit of vinegar I suppose due to evaporation. What is a safe way to dispose of the sludge? Many thanks.

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Welcome to IFI, Don6!

The acetic acid in vinegar reacts with the zinc to form zinc acetate, which is nontoxic and can be disposed of down the drain or on the lawn. You might want to neutralize any remaining acid with some baking soda first. 

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You may want to check what the laws are where ever you are at.  Where I live they have a hazardous waste collection several times a year that can be a safe and easy and CHEAP way to dispose of it.  Are you in the EEU, China, Iceland?  World Wide Web forum!

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In response to your other post on this subject. Zinc dust is NOT explosive nor particularly toxic. Zinc oxide can be toxic if injected in sufficient quantity. Zinc smoke can be toxic if breathed. Zinc is a necessary nutrient for a number of important bodily functions and we wouldn't last too long without. Zinc oxide is the main ingredient in sun screen and the white stuff you paint on your face in the desert.

Frosty The Lucky.

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I just neutralized my vinegar-zinc-rust sludge (barely any liquid left, the color of rust) with baking soda. I was surprised there was any reaction at all, but there was some foaming and bubbling. The sludge has been sitting outside evaporating for days. In my area of Nevada, there is a hazardous waste collection coming up in July. Thanks for all the helpful suggestions!

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Toxicity is a matter of quantity, not the material. There is a safe amount of ingested plutonium for instance.

Due to urban hype everybody tends to panic around galvanized steel or zinc in general. It takes a degree of mishandling to make it toxic and then you have to breath enough to do you harm. A person who has an allergic sensitivity will know long before they breath the smoke as it's so common they will have come onto contact long before.

We were just discussing forge brazing in another thread weren't we? Isn't forge brazing deliberately putting a zinc containing alloy in your forge? How about torch brazing, the gas welding bench in jr and high school metal shop class used to flicker with blue green zinc flames and "blue flu" was pretty common. Nobody ended up in the hospital let alone dead in my years of school or torch brazing.

So yes, do NOT breath zinc smoke it's NOT good for you but you do NOT need to run screaming nor call 911 and report a toxic chemical release. 

Frosty The Lucky.

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Yet I am willing to believe that areas of the world that took borax off the shelves due to it's "toxicity" might have requirements about zinc acetate sludge.  (And lets not forget CA labeling of play sand due to it's silicosis dangers!)  If the social requirements of your area require you to rub blue clay into your navel I would suggest trying to comply and reserve your battles for more important things!

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I forgot to suggest he dilute the residue not concentrate it. You have to live where you are, Alaska has some crazy stringent hazmat regulations. It's probably why you see so many leaky cans and drums on secluded roads. It cost me $160 to dispose of a freezer to extract and dispose of the freon even though it never contained ANY freon, it had been built about 15 years after the ban. Regs are regs though. Probably why someone had backed just far enough into our driveway to shove it out of their pickup.

Frosty The Lucky.

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Not in the hospital but one day in bed and one more day on the couch from brazing and inhaling the fumes.  This was the second dose of inhaling fumes a couple of years apart. Brazing is avoided if possible and NO zinc in the shop.

Zinc fumes mess with the respiratory system and open the door for other things like pneumonia etc.  We have an entire section on the site about zinc.  Better to be informed before you inhale rather than try to recover.

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If you grind etc on galvanized you are putting a lot of zinc dust and debris into the air which will settle on everything. This gets airborne again with any wind current, including you moving about in the area.  Then you breathe the material again.

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So Glenn, is your intent to foster hysterical over reaction to zinc? Once again you go into all the bad things zinc MIGHT do to a person and not a word about the much more dangerous things you can put in the air grinding. The % of people who suffer permanent harm from breathing small quantities zinc smoke is slight. Someone who suffers a relapse from a second exposure years later? Are you speaking for yourself or someone else? 

If you're that sensitive then by no means should there be any zinc in your shop. Can you drink water from galvanized pipe?

In your warning about grinder dust. Not ONE word about: cadmium, chrome, nickel, beryllium bronze, etc? THOSE are carcinogenic in the extreme meaning of the term and a couple have such a low threshold toxicity dose you don't want to handle the metal let alone heat, grind or weld them. How about wood? Remember the data sheet Slag posted with all the data about wood toxicity? 

Virtually NO wood is safe to grind, at the very least wood dust is an insidious irritant to eye and mucous membrane. Many though are outright toxic and can absorb through the skin. 

Don't react like I'm suggesting we don't take precautions. I'm suggesting we NOT foment unreasonable over reactions. Doing so causes people to disregard safety precautions when they discover something has been blown completely out of proportion.

Remember the reaction to the movie "Reefer Madness" when folks realized it was exaggerated beyond belief? People I grew up with assumed ALL drug warnings were exaggerated to the same degree and too many never made it.

Frosty The Lucky.

 

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My personal experience with inhaling zinc fumes was 4 very sick days the first time.  The second time was releasing zinc fumes from brazing.  I recognized what it was, shut everything down and left the building.  That resulted in 2 days of being sick.

Can people weld zinc coated metal?  Welders do it on a regular basis with the protection and caution, they feel is needed.  Look up the components in welding rods, and look up Monday morning flu, blue flu, and shakes, etc.

When I worked with HVAC ductwork, the cuts took much longer to heal.  I looked into it at that time and it was attributed to the galvanized coating, zinc.  The bare metal cuts from just days before did not have that problem healing.

All this was related to zinc as that was the subject being discussed.  

 

What about cadmium, chrome, nickel, beryllium bronze, etc, or wood toxicity?  You need to research the dangers of what you are dealing with, and what you are doing, before you start.  

 

IForgeIron has an entire section on safety.  It is worth reading.  Safety discussions

By putting the cautions out there, folks can then do their own research and make their own decisions.  

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So I WAS right, your dire warnings about zinc are based on your personal experience. Your level of sensitivity is in the VAST MINORITY. Recommending everybody take the level of precautions you need to is unrealistic. It's like recommending nobody eat peanuts or drink milk because lots of people are allergic, some deathly allergic. 

Correct, a cut from a piece of galvy will take longer to heal if you DON'T wash it with soap and water, just handling it dries my hands out. Soap, water and hand lotion takes care of that annoyance. A galvy cut for someone allergic WILL be more serious, do I have to say "of course)? Just walking into a room containing a peanut butter sandwich can cause anaphylaxis in the allergic. Do we ALL stop eating peanuts? Or do we take REASONABLE precautions, maybe hang signs saying peanut products are present? 

In reality in this thread, your post is related to YOUR experience not the zinc safety. YOU are sensitive YOU need to take stringent precautions, virtually everybody else on Earth can get a whiff or take common sense precautions and suffer NO ill effects.

This kind of exaggeration causes folks to not take warnings seriously, it's why emergency vehicles don't have their beacons on all the time, people become desensitized and WILL ignore them when it's maybe a matter of life and death. Same for safety warnings on the road if they're everywhere folks start ignoring them.

When somebody gets a dose of zinc smoke after all the dire warnings and discovers all s/he gets is a sore throat or mild headache, maybe a LITTLE upset stomach, think they'll take the warnings about forging cad or chrome plated steel as seriously? 

NO, they don't, I've personally stopped guys a couple times at club meetings from throwing chromed bolts in the forge to make square heads. They'd heard the warnings but didn't take them seriously. Zinc on the other hand would send them out the door immediately. Didn't know the brazing rod they were doing a forge braze contained zinc and nobody noticed. The more experience of us were keeping an eye on things so they wouldn't get carried away with it though.

Only fools don't take precautions and I've never suggested anybody treat zinc smoke lightly. I just want folks to take warnings seriously and these panicky dire warnings of impending doom do exactly the opposite, they make people ignore other warnings.

Just ease off the doom and gloom will ya?

Frosty The Lucky.

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I have been exposed to and used many things that would be a reason for caution.  Being a chemistry major introduced me to a bunch of stuff that you had to study about before you even considered opening a bottle.  Working with chemicals as part of the job was a new set of chemicals. 

Photography was a whole new level of weird when mixing your own developers for color slides, b/w and color negatives and other films, and papers, etc.  Then there was the ultra fine grain developers that used ingredients that you just knew to be careful about.  Many of these things could or would go through the skin.  All of this was done indoors so ventilation was important.

Life is dangerous so a little bit can not hurt and people tend to dismiss most of the dangers. It is common place.  Most mechanics just washed you hands in soap and water, or if they were really dirty, a solvent, and then soap and water.  Now they use gloves when working on vehicles. They used to save up and then pour used motor oil on dirt roads to keep the dust down.  If you life near a heavily traveled road, use a white cloth and wipe down the furniture on the porch.  You can get a collection of brake dust, oil and lubricants, dirt, rubber, and who knows what all else.  It coats the porch and house in a matter of hours, turning things gray.  You were also inhaling this stuff on the outside but also on the inside of the house.

The air you breathe can be a real problem when someone burns debris creating smoke.  When volcano erupt it throws huge amounts of smoke and debris into the air which is then spread over large areas.  Large eruptions hitting the air currents can cover several states or countries.  Forest fires put huge amounts of smoke into the air.  Large highways put huge amounts of exhaust and other pollutants into the air causing haze and pollution warnings.  

The southwestern United States is currently in a heat wave with many areas in excess of 100*F.  When it gets hot, increase hydration, but also set a temperature limit for when to slow down or quit until it cools down.  

A sore throat, a mild headache, a LITTLE upset stomach, or an uneasy or dizzy feeling means something is going on.  Many people dismiss these events and carry on, but those that are sensitive must be aware and reminded.  

It is not about doom and gloom.  It is about recognizing dangers and staying safe.  

 

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