Is rusted galvanized metal safe?

[JeyM]

So I see people talking about how you should stay away from forging galvanized metal, but I know that after a long time it can rust. If it's rusted would it be safe to smelt at that point? thanks

[Daswulf]

No, just cause it's rusty doesn't mean all the galvy is gone. And smelting it? 

[Steve Sells]

No no and no,  Read more, Starting with the pinned posts you have skipped.  

You dont even understand smelting, and even it the metal rusts where does the zink go? it doesn't walk away. but in your case go ahead,  your special and the posts about it all over here dont apply to you Right?

I just had minor surgery to get a tube in my ear and the pain increases so much when I lay down  I cant sleep, so I wont post any more to avoid making you more upset 

[Charles R. Stevens]

Smelt? You smelt ore to make metal. Are you talking about melting to cast? If so this is a question to be asked in the casting sub heading. Be warned casting steel is not a beginner skill, taking proper equipment, safty gear, as well as casting technic and safty technic. 

Now if you are acualy asking if it is safe to forge rusted steel that was formerly been galvinized is generaly yes, if all the zink coating is gone.  

Brother Sells, sorry to hear about the ear! 

[Marc1]

The zinc in galvanised steel acts as a barrier and as a sacrificial anode to protect steel but eventually will rust away and steel will start to oxidise, so if steel that was once galvanised is now showing brown steel rust, that means the galvo is on his last leg. In any case the presence of patches of zinc coating should be obvious. If steel rust is prevalent and all over the piece, the zinc should be gone. 

However ...

As it was repeated at nauseam in other threads, the risk of poisoning from zinc fumes is not worth a few cents of scrap metal. 

[ausfire]

Maybe you meant smite and not smelt. Yes you can forge rusted steel, but clean it as well as you can first. A few dips in the quench bucket helps too. Be aware that pieces of loose rust can come off the steel like a bullet when struck hot. Make sure your face shield is on.

And you need to come back and reply to this thread. Don't be offended or run away. Mr Sells is entitled to be a bit grumpy ... I would be too if I were in such pain. Best to you, Steve.

[Glenn]

One time some rusty pipe went into my forge for heating. The barely visible white smoke and the definite odor of zinc was produced and everything came to a screaming halt. The rusty pipe was, or had been, galvanized ! The end was flattened and then bent to identify the pipe as NOT to be used. 

Can you work with galvanized metal?  If you have to ask the question , , , , insert rant here.

Rule at my forge is NO galvanized metal of any kind.

 

[Charles R. Stevens]

Come on, Glenn you haven't gotten up to a good rant here in a long time! Lol. 

[JHCC]

12 hours ago, Steve Sells said:

I just had minor surgery to get tube in my ears and the pain increases so much when I lay down  I cant sleep, so I wont post any more to avoid making you more upset 

Feel better, Steve!

 

3 hours ago, Charles R. Stevens said:

Come on, Glenn you haven't gotten up to a good rant here in a long time! Lol. 

Although frankly, for succinctness and clarity, Steve's would be hard to beat.

[Glenn]

Lets see, read the stickies, Referenced to zinc, the entire section, and then read the 30 or so posts in the safety section.

I can give you the name of Jim Paw Paw Wilson to look up the particulars of zinc fumes along with his obituary. Zinc fumes DID NOT kill Jim, he had COPD and other breathing problems. The zinc fumes from burning off the galvanized zinc coating from some sections of pipe in his gas forge, opened the door for pneumonia, a hospital stay, double pneumonia, another hospital stay and death. All this in about two weeks time.

I personally have had 2 (two) episodes with zinc poisoning and the ONLY way to win with zinc is to NOT play the game. (my opinion).

 

 

[Frosty]

Welcome aboard JeyM, glad to have you. If you'll put your general location in the header you might be surprised how many of the Iforge gang live within visiting distance.

Please don't take the responses to your questions, personally folk just don't want you messing with dangerous things when you pretty obviously don't know enough to do so safely. Please do some reading, you need to at least learn the craft jargon or you'll never be able to ask good questions nor understand the answers. You can NOT smelt refined metals, no matter what some . . . person on Youtube says or what they call it in a game.

I'll use your question as an example of why having at least a working handle on the language is important. You've done enough reading to know how many folk say NO GALVY in the . . . what? Anyway, Galvy bad is a good start. Do you know why zinc is considered so dangerous? Iforge has a LOT of info archived in titled sections. You ask about rust and galvy. Decent question but to judge if galvy remains on rusted steel it requires a level of experience you just do not have. For this reason most folk are going to try to discourage you from messing with it at all. Lastly you use a term that has NO connection to the things you're asking. Smelting is a first step in refining ore into usable metal. It has zero connection to the materials you asked about. It's a non sequitur on the order of saying you're buying a sail boat and asking if low profile tires wheels should be chromed or wire brushed.

Get well soonest Steve, not being able to sleep sucks BIG TIME.

There's a thing folk don't know or think about working with galvanized pipe. It's galvanized on the INSIDE too, that's what happened in Glenn's incident. The outside looked and probably was safely de-zinced but the inside had been sheltered from the environment enough to retain the galvy.

Please stick around, we're actually a darned friendly bunch but we don't like seeing folk playing with dangerous stuff until they've learned enough to do so as safely as possible.

Frosty The Lucky.

 

[JeyM]

Thanks for the clarification. I'm sorry that I didn't word my post better, I'm just new to blacksmithing and I was also tired but its more just being new. I am also new to forum type websites like this so I wasn't aware of some of the things I should have done before asking my question. What I was trying to say in my question was: I know that it is unsafe to forge galvanized metal because of its coating, however, I also know that over time the coating can break down enough to where the metal is able to rust. If the entirety of the metal is rusted then would enough of the coating have broken down/worn off to allow you to safely forge it. Again sorry for my rookie mistakes.

[Marc1]

9 minutes ago, JeyM said:

........ What I was trying to say in my question was: I know that it is unsafe to forge galvanized metal because of its coating, however, I also know that over time the coating can break down enough to where the metal is able to rust. If the entirety of the metal is rusted then would enough of the coating have broken down/worn off to allow you to safely forge it. ......

You are right in theory. In practice, the red rust can develop around and even over some patches of residual zinc and make seem to be fully rusted when it is not. Furthermore if you are talking about galvanised pipes, the exterior of the pipe has a lighter coat of HDG than the inside that is usually much thicker. A pipe that has been in use with chlorinated water may be fully rusted inside and free of zinc but when it reaches that state it is but a useless clump of rust and worthless for forging. There are copious cases of poisoning by welders and blacksmith and the risk is not worth it. Best to collect scrap that is not hazardous and make your blacksmithing learning experience a pleasurable one. Keep on posting about your endeavours. 

[JeyM]

Thanks marc1, I'm mostly concerned with just being able to identify metal that has been galvanized because once it's at that point I don't see how you could tell the difference.

[ausfire]

1 hour ago, JeyM said:

Thanks marc1, I'm mostly concerned with just being able to identify metal that has been galvanized because once it's at that point I don't see how you could tell the difference.

Apply some hydrochloric acid - if it bubbles it's still got zinc there. Don't breathe the chlorine.

[SLAG]

Aus,

The hydrochloric acid will turn the zinc into zinc chloride releasing hydrogen gas. No poisonous chlorine gas will be generated. BUT do not let that hydrogen gas get near a flame or heat source. Like a lit cigarette.

We could use vinegar instead of HCl. It does a good job but the reaction goes a little slower.

Regards,

SLAG.

[ausfire]

Slag,

Thanks for clarifying that. Chemistry wasn't my strong suit at school. I assumed since hydrogen is odourless that there must be some chlorine about to give the gas that comes off the zinc/HCl reaction such a pungent sharpness. You don't want to get near it!

[gote]

It is probably not chlorine Ausfire. More likely to be small amount of hydrocloric acid carried into the air by the bubbling.

I have some experience of hydrogen fire and it is not particularly dangerous in an operation of this type because the amounts generated is small and it is not confined in a vessel that may burst. However, mixtures of hydrogen and air will usually detonate when ignited (Meaning that the flame propagates faster then the speed of the sound) so there is bang like a gunshot. Gasoline or propane leaks are much more dangerous.

I remember a welder being scared out of his wits when he was welding above a foam of hydrogen in water (at least a cubic foot of the stuff) Whenever a spark fell into the foam there was a noise of shotgun level but absolutely no harm to anything whatsoever.

I think smoking is generally bad for you and in this case more so than usual becuse you might get your moustache singed off.      

[JosephKen]

Most of the people tend to avoid used galvanized materials. Whether for welding, forging or plumbing, it is always better to avoid this material. Rusted galvanized metal can turn very toxic so please don't use it for forging. In case of plumbing too they can turn into a toxic material. Here is an article which gives details on why they are toxic.

What is galvanized steel?

Galvanized plumbing are steel pipes that have been covered in a layer of zinc. These pipes are more susceptible to corrosion and, over time, the buildup of rust leads to the release of the toxin Lead. Aside from a host of health issues, this build up of rust within the walls of the pipes can cause low water pressure or discolouration in your water supply as a result of iron deposits.

What are the risks? Aside from decreased water pressure, lead buildup will result as galvanized steel corrodes. The risks of lead build up are well-documented. Long-term exposure, especially in children and pregnant women, can cause serious health problems from developmental delays, premature birth, cardiovascular effects and more.

So the water and fumes from rusted galvanized metals are always toxic and not safe for our health. Don't go for it. 

[Glenn]

Let us think about this information for a moment. Steel covered with a coating of zinc makes the steel more susceptible to corrosion? Then why coat it? 

A buildup of rust leads to the release of lead. So where did the lead come from?

Wikipedia: Galvanizing is the process of applying a protective zinc coating to steel or iron, to prevent rusting. Although galvanizing will inhibit attack of the underlying steel, rusting will be inevitable after some decades of exposure to weather, especially if exposed to acidic conditions. For example, corrugated iron sheet roofing will start to degrade within a few years despite the protective action of the zinc coating.

 

A discussion on zinc can be found through out the IForgeIron site.

[ThomasPowers]

Context!  This is obviously from a text dealing with plumbing and particular older plumbing where lead has been used as part of soldered and packed joints and even for piping. It's worried about lead in the water, there are a number of webpages dealing with the issues that Flint Michigan had when they changed the chemistry of their drinking water and how that increased the lead content.

Some of the older water systems in areas that get cold still had grandfathered in lead pipes running from the water mains to the houses to deal with freezing issues.  We have new piping that can deal with these but replacing thousands to millions of deeply buried pipes in 100 year old neighborhoods is a big problem!

So lead is not an issue heating galvanized steel save for the tendency to use lead based paint on steel in earlier decades.

Rusted Galvanized metal is no more toxic than fresh unrusted galvanized metal in the forge.

[SLAG]

Greetings,

People living in areas that have hard water are less likely to have lead in the drinking water. The lead pipes quickly had their interiors coated by precipitated calcium. That coating was deposited by the calcium in the hard water. The coating shielded the  water from the interior lead pipes and spared consumers from taking up much lead.

 This phenomenon will NOT happen in areas where the water is soft.

So the cheap, politicians and engineers are willing to let well enough alone. The cost for total removal would be monumental.

Fear not.

Older city areas with one hundred plus year old pipes are only now beginning to fail. This will force municipalities to replace those old legacy pipes. (they built exceedingly well at the end of the nineteenth and early twentieth century).

Given enough time, there will not be any lead water pipes in North America.

SLAG.

[ThomasPowers]

I've seen roman era lead pipes still carrying water.  There is a reason the word for plumbing comes from the word for lead!

[SLAG]

T.P. ,

The Roman's built even more robust pipes than the municipalities of 100 plus North America.

But the Romans poisoned themselves by using white lead carbonate for sweetening their food. Beat and cane sugar came into use many hundreds of years later.

The Romans had honey for a sweetener. (besides the lead carbonate).

Regards,

SLAG.

Some historians have even theorized that chronic low level lead poisoning was a significant factor for the decline and fall of the Roman Empire. Why? because lead poisoning causes brain damage that lowers intelligence