Heating galvanised reinforcing bar

[Old Boiler]

Heated some short gal reo lengths (hot dipped) for a mate (well ventilated and protected) which snapped when trying to bend it. They would however, tolerate a cold bend.
What happened?
Did the burning of the zinc change the metallurgy of the steel?

Jim.

[Fosterob]

How hot did you get it?
Rob

[macbruce]

Heated some short gal reo lengths (hot dipped) for a mate (well ventilated and protected) which snapped when trying to bend it. They would however, tolerate a cold bend.
What happened?
Did the burning of the zinc change the metallurgy of the steel?

Jim.

No....But I reckon they put more scrap in rebar than mild steel.....Is the steel hard after it air cools?
Removing zinc is no bother with small pieces.....Just soak it in a mild solution of muriatic acid (just enough acid to make it fizz) and in a few minutes it's dissolved........

[WmHorus]

NEVER EVER EVER PUT GALVANIZED STEEL INTO THE FIRE, unless you WANNA DIE. Galvanized steel heated gives off Zinc Gas which is Poisonous and will kill you if you breath in enough of it. Sorry for the Caps but I cannot strongly enough emphasize that as a NO NO

me

[clinton]

You are talking about rebar? Lots of different types of rebar, some can not be welded, it it manufactured to do a specific task and may perform in strange ways when you try to do something that it was not designed for.
I had a foreman tell me to bend some rebar for hooks to attach a man basket to- I told him no way you get the proper equipment. He was quite intent on using rebar to do this and got a bigger rod saying that it was more than strong enough for the job- I told him he could get my check before I would not do it. He went and got some shackles and we were able to get the man basket up

[WmHorus]

I posted a harsh reply about zinc on the blade forum and had people obviously start telling me to shut up that Zinc aint all that dangerous.

Post edited and the Link removed at the request of Anvilfire.

[MattBower]

It isn't, or thousands of welders and brass founders would be d-e-a-d. But it'll make you feel like crap, so it's still a very good idea to dissolve the Zn with an acid before you heat any galvanized material

[Timothy Miller]

I too have experienced surface cracking while forging galvanized steel something I almost never do BTW. I think at a certain temp the zinc is absorbed into the surface of the steel and it causes embitterment just a guess on my part, though I have no idea why. Its best to strip it off with hydrochloric/muriatic acid before you forge it removes both problems.

[MattBower]

That could be. A metallurgist once told me that it's a bad idea to use molten tin to heat steel for hardening (I was wondering whether it'd work as a substitute for molten salts) because the tin gets into the grain boundaries and causes problems later.

[MattBower]

On the other hand, I've had non-galvanized rebar behave badly under the hammer, too. Maybe that's the problem.

[Frank Turley]

An excess of sulphur in the melt when the steel is manufactured can cause red-shortness.

[Timothy Miller]

I have also seen this problem when I have heated steel in my gas forge and there are bits of bronze in the floor of the gas forge. This molten bronze wicks onto the steel and destroys its integrity mostly in the form of pronounced surface cracking.

[Rich Hale]

I have stick welded alot over my life and some of it was on galvanized. Took me quite a while to relate the bad feelings the next few days to the welding on Galvanize,,I suppose that is a familiar story to a lot of you on this forum. The fumes from heated galvanizede steel are hard to relat to toxicity as we all know that toxicity is dosse related and in most cases depend on individual tolerance and past history including preexisting medical conditions.So how many times can you do this before it is a true danger? Thats the problem there is not set answer. As a retired fire captain i have seen the results of misue of gasoline and the painful injuries from that. And in most cases if they could and would talk to me they all said a similiar thing; They had done it before and never ever had a problem. That is not exactly like heating galvanized metal except for the part about it never being a problem,,,until!
Maybe toof ar down this long road i tend to pay more attention to a saying from long past. If I do this wot is the worst thing that can happen?,,,
In this case the worst thing that can happen makes it simply easier to make a right decision and find other things to do instead. This forum lost a good friend to all of us from the fumes from this very operation. The Drs at the hospital where he wsa taken did not find out the source of his illness, He researched it on a puter and found that the symptoms from this type of poisoning were exactly wot he wsa experiencing. And which took his life.
Bottom line is do not think this is a little or no danger to you,,,It is more like a posonous snake. Some of then can bite you and not kill you...easier to leave them alone.

[SmoothBore]

Some re-bar is just brittle, and full of inclusions.

It has limited applications, ... and those "limits" will occasionally give you trouble.

Take every opportunity to avoid using it.


As for the issue of molten Zinc .....

The most common Zinc alloy, used in hot dipped Galvanizing, is the #3 alloy.

It melts at about 788 degrees Fahrenheit.

This means, that you don't have to "burn" it off a steel part.

Just heat it a bit, ... IN A WELL VENTILATED AREA, ... and wire brush it off.

If an acid bath is available, by all means, go that route.


Zinc IS a "heavy metal", ... and it's fumes will cause heavy metal poisoning, ... so of course, it needs to be respected.


From the mid 1970's to the mid 80's, I was Superintendent of a Company that did Zinc Die Casting.

During that decade, I experienced a headache or two that I attributed to Zinc fumes, ... but it's equally likely, that an over-rich Natural Gas mixture, in the melt furnaces, was the cause.


The point being, ... that a well ventilated work place is ESSENTIAL to ALL manner of "hot" work.


There is Zinc, ... and other heavy metals, ... present in many different, commonly encountered materials.


You won't always know it's there.

But Carbon Monoxide WILL always be present, in any forging atmosphere, ... and that's reason enough to be cautious about ventilation.


.

[Rich Hale]

I am thinking you meant to say carbon monoxide which is the bad actor in alot of places, And like you mentioned especially in and around forges. Carbon dioxide will harm you if ithere is such a rich mixture of it that it leave you not enough air to breathe. like that it makes soda pop fiz.....lol

[glen56]

remember seeing a plea from a blacksmith in the states 10 or so years ago who stated he was dying from putting gal into a forge ,have done it myself ,never again ,reckon dont do it ,evil gear,glen

[SmoothBore]

I am thinking you meant to say carbon monoxide which is the bad actor in alot of places, And like you mentioned especially in and around forges. Carbon dioxide will harm you if ithere is such a rich mixture of it that it leave you not enough air to breathe. like that it makes soda pop fiz.....lol

Of course, you're right.

Getting old and feeble minded, I guess. :(

[Jack Evers]

Back in my 20's (50 years ago), I built a stock rack for my pickup using galvanized pipe and an O/A torch. I still remember how sick I was and haven't repeated the exposure since. Sure, I've done a bit of heating on zinc containing materials, but only with good ventilation and caution.

Remember that brass is a mixture of zinc and copper.and can give off fumes. A common horseshoeing application is to apply drill tec ( a mix of braze metal and tungsten carbide particles) for enhanced wear and/or traction. I do this in my gas forge and see the white zinc oxide build up around the door, but I don't have my face into it like I would using a torch.

To second Southshoresmith,about bits of bronze (more likely a braze metal containing zinc - bronze is copper and and tin and brittle) in his forge causing problems with heating steel later, I remember a forging contest where I beat one of the nations good competitors because he couldn't get his forge weld. He said it was because he'd been doing some brazing and still had traces of it in his forge. Probably correct.

[Ted T]

I believe this is one of the most important and responsible topics that could be brought up here at I Forge Iron.
Thank you all for taking a responsible stand on this topic!
Even if you disagree with my opinion, please error on the side of safety with this issue!

To disarm new craftsmen of the potential dangers of welding or cutting galvanize products may have a serious outcome.
I feel a great in-justice may be done to unwary readers when someone who is not fully informed about the reality of the cause and effect of Galvanized Poisoning give there untried opinion that says it’s OK, that all you have to do is just drink milk.
I think milk may help settle your stomach if I remember correctly, but what about the long term effects?

It seems as though some of the content contained in a few posts that I have read over the last few years that have mentioned the topic of “Galvanized, zinc, fumes, and milk”, have a tendency to water down the real or potential long lasting effects of Galvanize Poisoning.

They would say something like “I have welded on galvanize for 263 years and all I done was drink milk and I am just fine”.
Of course I am exaggerating. But posts like that seem disarms the reader into thinking that it is no big deal.

BUT, galvanize poisoning is a big deal and an issue that should be taken as a priority to learn how to manage the use of it safely.

I can assure you it is a big deal because I have experienced the stark reality of the very real and long lasting problems that derive from welding or being exposed to Galvanized Steel fumes with out proper ventilation.

When I was young (in my 30’s) I needed a job real bad to support my large family that I had adopted. So when we would say something about the lack of ventilation in our shop, they told us that they had a pile of applications on the desk, that if we did not like the conditions that existed we could be replaced.

I have had to live with the outcome of this issue first hand. And it was not pretty!

So with out going into the details of a real long story, I will tell you this;
Back in the 60’s at the University of Utah hospital, when I was going through treatment they also called it “Products of Combustion that had settled the Bone Morrow” or Galvinize Poisoning. I am no doctor; I am just repeating what they told me.

Story: I was the one of the lucky ones out of the four welders who worked in our shop at that time.
Within two years, one of them died of a heart attack; he was only in his 30’s. They don’t know what caused the attack.
I lost the full and effective use of my left hand, arm, and leg. It took between 4 ½ years to 5 years for me to have full and comfortable use of my arm and leg again. Plus I had to have a stomach operation from taking too many aspirins that I was told to take by the doctors. .

Oh, and the guy who took my place is now a total vegetable. With in a year after taking my place, he had the same symptoms that I had. He never recovered.
And the fourth guy only did bench welding and was never required to carbon arc and weld all day inside of garbage trucks or on galvanize pipe. He was just fine.

No doubt that some people will never have a sever reaction to galvanize poisoning as other people may have.
We need to recognize that what will adversely affect one person will not necessarily have any effect on another person. Just like medication reactions have on different people.

The old (WWII) doctor who treated my fellow welder gave us the following summary of information.
During the Second World War a problem developed within the vast numbers of welders that supported the war effort. The government had hired thousands of women to become welders in the arms plants.
All of the able bodied men were off fighting the war.
Health problems started to show up with some of the welders. It turned out to be galvanize poisoning. But the problem was that it only showed up randomly.

The Doctors scenario was that when several people were doing the exact same type of welding and had the same exposure to fumes, some got ill, and some did not show any ill affect at all.

This same old doctor came to the conclusion that it was dependent on an individual persons ability to resist the effects of how, and if the same amounts of exposure would affect them at all.
I believe each contributor needs to be heard and what they say needs to be evaluated by the reader.
Even if you disagree with my experience, at least I Forge Iron have given us a platform to give our views to banter back and forth.
In the end, the reader has to make a decision of how close to the edge of life they want to live (or be sick, or die).
My very best to you all!
Ted Throckmorton

[John B]

I'll stand up and be proud to be by your side on this one Ted, 110%

This is one instance where it is better to gain by others experience, than by learning the pitfalls by yourself.

[Glenn]

The internet is a strange place and not all the information it contains is factual.

One site has posted under the name of a member that has died. The author (whoever that might be) states " I did something stupid ...... and now I am dead" then goes on with the post. Why post under the name of a dead man as if it were his post? Why then add additional material at a later date (under the dead members name) to a locked thread? This, in my opinion, throws a shadow across the information presented.

As WmHorus experienced, something he thought was dangerous sparked conversation that it was NOT all that dangerous and to shut up about it.

IForgeIron is about safety and keeping you safe through education. This education includes what to stay away from, what dangers you may not be aware of, and where to go to find material on the subjects so you can make your own decisions. Personal Safety is just that, YOU taking personal responsibility to keep YOU safe. You can only do that if you know what to do, how too do it, and seek out the information you need for your project. One opinion written by an unknown poster is not conclusive proof or the information you need. Seek out the experts in their fields, study multiple and reputable sources, do YOUR homework. *Hey y'all - watch this* makes good video but can and most likely will get you hurt.

Personal Safety is just that, YOU taking personal responsibility to keep YOU safe.

[MattBower]

I agree making people aware of dangers. I don't agree with effectively lying to them concerning what we know about the dangers, in order to scare them beyond what the facts support. I have lost friends to car accidents; it does not mean I will tell people that, "IF YOU DRIVE, YOU ARE GOING TO DIE!!" I can find exactly ONE example of a death that may have been caused by burning massive amounts of zinc in an enclosed space (a stupid thing that I would never advise anyone to do, and never have), and that was a man with emphysema, who ended up coming down with double pneumonia. As far as I can tell from what's posted online, that -- pneumonia - is what finally killed him. And frankly, I'm not sure that large amounts of any fine particulate might not have have caused pneumonia in someone which such severely compromised lungs. (I would note that fumes from many other metals can also caused metal fume fever. Zinc is just a particularly common culprit because it's used a lot, and because it has a relatively low boiling point).)

The question concerning long-term effects of inhaling zinc oxide is completely legitimate, although it may or may not be relevant that zinc is not like many so-called "heavy metals" in that it is necessary for life and your body does excrete it. (I'm not certain how inhaled zinc oxide relates to ingested metallic zine.) But if we are going to speculate about the possible dangers of long-term zinc exposure, there is no reason we should not also be equally vocal about the possible -- or sometimes even well-established -- long-term dangers of cadmium (more common than you may think, and clearly much more toxic than zinc), flux fumes, various alloying elements in certain steels (manganese, chromium and lead come to mind), ceramic wool fibers from our forges, silica dust from foundry sand (if you cast), clays, and castable refractories, carbon monoxide -- there's just a whole long list of dangers inherent in the things we do. And that's just the respiratory stuff. Cataracts from long-term IR exposure? Sure! It goes on and on and on.

Warning people about dangers, and recommending ways to mitigate those dangers -- e.g., by dissolving zinc off the surface of galvanized materials before exposing them to high heat -- is the right thing to do. I absolutely agree with that. But I also think it's downright wrong to in essence lie to people -- adults in particular -- because you've decided it's for their own good. "If you burn galvanized you WILL DIE" is a claim that appears to have almost no support, at least in the short term. One guy may have gotten that result, but thousands upon thousands of others have been exposed to ZnO fumes and NOT gotten that result. In fact we have several of them posting in this thread.

That does not mean it's a good idea to burn zinc, especially without taking any precautions. It isn't. But it's a bad idea mostly because it'll make you feel awful for a few days, and because we're not sure what the long term effects may be -- not because it provably *WILL* kill you, no matter what. At least give people enough respect to lay out the known facts, to speculate responsibly about dangers that may not yet be fully understood, and to let them make up their own minds about how much risk they're comfortable with. People who aren't willing to accept any risk should not be involved in blacksmithing. Or life, for that matter.

[Rich Hale]

I surely hope that nothing I have posted on here can be taken as me saying if yoi heat galvanized metgal you will die..It is a hazard I have removed from my life forever.

MAybe It would be less of a fuss on here if we disussed smoking tobacco?

[Old N Rusty]

Use a fan to blow the galvanise fumes away from you. It is so simple!I have torch cut miles of galvanized floor grating. Carefully,making sure the air I was breathing was clean.

[MattBower]

I surely hope that nothing I have posted on here can be taken as me saying if yoi heat galvanized metgal you will die..It is a hazard I have removed from my life forever.

MAybe It would be less of a fuss on here if we disussed smoking tobacco?

That certainly wasn't direct at you, Rich. That's basically how the first warning to the OP was phrased, and I really don't agree with that way of doing things. But there's nothing wrong with telling people they'll probably be much better off if they don't burn zinc.

Smoking? You go ahead and take that one. lol