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Toxic effects from galvanized food preparation utensils, page 2


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+++++++

We are planning on making some wiener roasters for a craft, is galvanized wire OK to do so? Thank you, Carrie form Vancouver, Washington

Carrie Walters
- Vancouver, Washington


+++++++

Sorry, Carrie, but no, it's not okay. Zinc is not supposed to be used as a cooking surface for food.

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey

+++++++

I have a galvanized tub for collecting rainwater. My cat licks the galvanized surface of the tub all the time. Is this dangerous and should I remove the tub? Also, why is she doing this? Is she absorbing something or might she just find it tasty?

Erica Freiberg
- Paris, France


+++++++

Geez, this thread never ends, does it. So here is another question for it.

We are just about finished renovating our home and, in the process, removed an ~5 ft water tank that was used to hold the water pumped from a now-defunct well. The tank appears to be galvanized and was manufactured ca. 1950.

What I was thinking of doing: take it to the local welding outfit and have it cut lengthwise (exact design tbd) and weld on hinges, use if for a BBQ pit and maybe a smoker. I have no intention of cooking directly on the galvanized steel and can put non-galvanized grates at the bottom on which the fuel (charcoal, wood, etc) could rest.
- Is there ANY known risk in recycling this tank in this way?
- Does the age of the tank give an clue as to the composition and, by extension, the risks of using the tank?

Thanks in advance,
Jim

PS. If anyone has a good design idea for the BBQ/Smoker, feel free to share with me!

Jim Greenfield
- Greenport, New York


 

Hi, Jim. My guess is also that it's galvanized, although I suppose it could be tinned. Zinc is not a toxin, it's an essential nutrient. The danger is in overexposure/overconsumption. I'm just a metal finisher, not a dietician, but my understanding is that there are three paths to that overconsumption:

1. When welders weld galvanized materials without adequate ventilation, vaporizing the zinc and inhaling clouds of it.
2. When acidic foods dissolve some of the zinc that they are touching and it is ingested.
3. When galvanized tanks and piping are used for water collection and storage.

I know that the first case of overexposure is very real, and we have several threads on that topic on line here. Regarding the second case, I know that government bodies consider zinc to not be a "food-safe" surface, but I'm not personally aware of actual issues from this. Regarding the third case, galvanized materials were used for water service for decades, but I think they no longer are in the USA; certainly they are still used in the third world and for livestock feeding and watering.

I don't think there will be any problems with your application, beyond breaking a finger if the top half of this heavy tank pivots down suddenly :-)

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


+++++++appended

Hello, my name is Steve and I have pieced together a charcoal bbq using 16-ga galvanized steel. I was told by a part time welder that using galvanised steel is not a good choice of steel and that it will contaminate my food?

I am not cooking on the steel, but just using it as a shell to hold the charcoal. I have a stainless steel grill that will be elevated over the bbq, similar to a rotisserie grill. I just want to confirm if what I am using is safe?

Steve

Steve Da Silva
hobbyist - Toronto, Ontario, Canada


January 27, 2008

I currently have a galvanized bar top that my toddler eats off of; he mainly eats off of a placemat, but sometimes he will place the food over onto the bartop and eat that -- should I be concerned about poisoning and if so, is there any coating I can add to this top to protect it from leaching?

Shari Robins
- Fairview, North Carolina


 

Hi, Shari. There are lots of people building galvanized countertops and solid zinc countertops. Still, the government doesn't consider zinc to be a "food-safe" surface, and I certainly can't say "listen to the countertop builders and ignore the NIH" :-)

But unless your toddler is constantly eating sliced tomatoes from the bare countertop, I think the issue is de minimus.

Getting good adhesion of paints and clearcoats on galvanized steel is notoriously difficult, and you don't want your toddler eating paint chips, so I wouldn't coat it.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


April 12, 2008

Will it be safe to make an exhaust pipe from galvanized to make a exhaust pipe for a bbq smoker. thanks

Jared Smith
hobby - Bonham, Texas


April 21, 2008

Hi, Jared. The exhaust pipes on furnaces and hot water heaters inside your house are usually galvanized, so I don't see why not. Good luck.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


April 20, 2008

OOPS! I used a self-made galvanised wire rack to puff up the crackling on Pork Rashers that had previously been grilled. Have I poisoned my family?


Tessa Joughin
- Ficksburg, Free State, South Africa


April , 2008

Hi, Tessa. 'Poisoned' is a very strong word. Paracelsus tell us that only the dose makes a poison. I would not worry about it in the least :-)

I think the operative thing to learn is that things that are not intended for food service should not be used for food service. Because then we build no public history; so no researcher can possibly say "Wait! I see a pattern here" if people are using such materials privately with no feedback. See if a store has a stainless steel or nickel plated rack that might serve.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


April 22, 2008

Thanks Ted, I feel much better! I will throw out my brilliant invention and see if I can find a stainless steel one to replace it!

Tessa Joughin
- Ficksburg, Free State, South Africa


September 7, 2008

Hi Ted
I enjoyed your enlightening responses & don't need to ask my question now. You have the patience of a saint - thanks. We used to cook sausages on galvanised wire as children. Perhaps that's why I have a warped sense of humour.
You neglected to inform the lady with the zinc licking cat that the cat will be unfit for human consumption. I actually love cats (but I couldn't eat a whole one).
Bruce

Bruce Johnston
- Hamilton, New Zealand

Ed. note: Thanks, Bruce. That's what kittens are for. -- Ted


September 10, 2008

I understand that zinc is an inappropriate material for a cooking surface. I have read the string of questions and answers carefully. But here's my situation: I need to generate a quick blast of steam for bread baking. One chef suggested that I put galvanized nuts and bolts or galvanized chain link on a sheet pan, heat to 500 degrees F, and then pour water on them just before putting the loaves in the oven. Sure enough, the hot steel creates a great deal of steam for a few minutes. The bread is not in direct contact with the galvanized metal, but it is in contact with the steam produced. Is the presence of moisture and steam any more likely to cause a problem or toxicity on the food? Many thanks for your wisdom.

Eric Martin
- San Francisco, California


September , 2008

Hi, Eric. You are nowhere near hitting the vaporization point of zinc, so I don't think there will be any zinc in the steam. But stainless hardware is readily available and sounds easier than trying to justify yourself:-)

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


September 22, 2008

Hi. Many thanks for your advice. Yes, I guess I was just being cheap since stainless hardware is so much more expensive.... But I think I'll just do the right thing, as you suggest, so I don't have to wonder every time I bite into a piece of homemade toast...!

Eric Martin
- San Francisco California


September 23, 2008

I have an old washing machine and want to use it to build a smoker. There will be a non galvanized fire pit attached to the side. The shell of the machine will only be used to hold the grates for the meat and to act as the smoke box never getting over more than 300 degrees F. Is this ok since it will not be direct heat?

Thanks

Zak Siska
- Warrenton, Virginia


September 24, 2008

Hi, Zak. Unfortunately it's hard to say. Who knows what the old washing machine is made from and what surfaces may be in it. It's possible (perhaps unlikely, I don't know) that there is cadmium or lead on the surface for some reason. The general principle is that when we use something for a purpose for which it wasn't intended, we take risks because the designer had no intention of it being used as a smoker and there's no good feedback system in place to learn if people are getting sick from similar stuff.

I am not a scare monger or chemophobic myself . . . I just have no idea what the old washing machine might contain.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


November 7, 2008

Hi! I have carefully read all of the previous posts, and promise to never cook with items not intended for that use. I do still have a question.

I am organizing a craft night for my elementary/middle school, and the instructions tell me to give the children lengths of galvanized wire. So I went and bought some. On the package, it tells me that it contains chemicals that cause cancer, birth defects or other reproductive harm. and to WASH HANDS AFTER HANDLING. Ok, we are talking K-6 grades, and I can guarantee at least one kid is going to touch the wire and then stick his fingers in some orifice of his face. Now I know that many products have warning labels just so they don't get their pants sued off. Is there really a danger to the kids just touching the wire? It will not be heated in any way, but they will take their projects home, and perhaps lick the wire on the way.

Thanks for the help, and the laughs.

Monica Pardel
- Midland, Michigan


November 7, 2008

Hi, Monica. We both just conceded "plausible deniability" :-)  -- so no, it's not okay.

Some people perhaps think California is doing a public service by warning people that everything is dangerous in one way or other; but many of us who have taught safety courses, and know that mechanics are obviously not going to scrub their hands every time they touch a zinc plated nut or bolt, think California is doing a great disservice by crying wolf and ingraining the habit that we can safely ignore such warnings. California fruit flies :-)

It may be a bit harder to find, but aluminum wire might be best and is inexpensive. Stainless steel stranded wire would be safe and they make it stranded for less springiness. Anything labeled craft wire is probably safe, although wire that is not aluminum, and is not stranded, might be springy.

Thanks for your great patience in reading this whole thread, it's gotten very long.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey

Aluminum Craft Wire



Wire for Beading


March 19, 2009

We use galvanized mesh to dry apples, which is a foot or so over our wood stove the mesh is above the stove when not used for drying, so is exposed to various degrees of heat on a regular basis. I scrub it before putting apples on it to dry. Your response re: use of galvanized wire for roasting hot dogs seems to be in the same category, should we NOT eat the dried apples?

Thank you !
Peggy

Margaret Niesen
- Ellsworth, Maine


March 26, 2009

Hi, Peggy. In view of the previous discussion that you are expanding upon, I think you are not asking quite the right question. I think the question you should be asking is: "Should we continue to use galvanized wire for this application?". And my reply will be: "No, you should find stainless steel or nickel plated mesh".

When you pose the question you have posed there are 1001 nuances, and all you can get are opinions from people (including me) who don't know all those subtle little details. Personally, I'd eat the dried apples though. Waste not / want not.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


March 28, 2009

Someone asked about a trash can smoker.
I'm making one now, but not using a charcoal briquette, a hot plate and a cast iron smoker box instead and a meat thermometer to monitor the heat. You can get the smoker box at any hardware store. The temp stay's less than 150 deg F. doing it this way. The design I see at this website I don't like because of the high heat inside the can I think ""could"" cause a release of toxins. Also I wouldn't use the Teflon coated Bundt pan as shown here on the coals. Personal pref.

I can't imagine the zinc would ever come in contact with the fire or food. Should be ok?
http://winecanine.com/smoker.html

My idea comes from Jeff Smith, The Frugal Gourmet, and one of his small cook books.

Let me know if there are other concerns I should have with this please.

Tom Harris
- Fond du Lac, Wisconsin


April 5, 2009

Would it be safe to use a old galvanized wash tub as a fire pit? No food will be involved, just burning logs.

Kim Ruiz
- McHenry Illinois


February 19, 2010

question. I have what could be a great grill. But, how can I know if it's galvanized?

Paco Morales
- Panama City, Panama


February 23, 2010

Hi, Kim. I personally think it would be fine. It's not 100% amenable to logic; people have to pick their own fears and phobias :-)

Hi, Paco. If it's spangled like an ash can, it's probably galvanized. If it looks like it's dipped in zinc, drippy like a roofing nail, it's probably galvanized. Sorry but your inquiry is a bit cryptic. You have a commercial grill, an old grate, a piece of sheet metal, a drum, or what? Good luck.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


April 13, 2010

This thread is a little old so I hope I can still get a response from Mr. Helpful and Very Patient! I KNOW you have been asked many of the same questions here. One question is actually the same one I have....except I never saw a response for it and I did read the ENTIRE thread to be sure my answer wasn't here.

I want to cover our kitchen table with galvanized steel. I really don't want stainless for various reasons and also liked the look of the galv. We have 2 small children, one of which is 3 and very likely to drop her food on it and eat off of it. (a guarantee, actually)

I did see one post that expensive mansions had this as a food prep surface (and the link you provided for her wasn't working anymore)...but the toddler question is much closer to mine since this is where our family sits and eats all meals. And that's the one I didn't see an answer to. Would be ever so grateful for some clarification! I also found this (http://www.galvanizeit.org/images/uploads/drGalv/hdgsteel_food.pdf) - but with my kids, I can never be too careful and want to do the right thing. Eating occasionally in a restaurant with it might be ok - but is 3x a day everyday? (of course, this is only assuming food droppings are eaten directly off of the table)

Laura Glcy
- Marietta, Georgia


April 14, 2010

Hi, Laura. My statements are nothing more than personal opinions driven by my own personality which is generally pragmatic: which means I don't think you should install a galvanized countertop, but if you have already done so, I don't think you should rip it out :-)

Zinc sheeting and galvanized sheeting aren't really the same thing. The zinc sheet used in the old mansions (and in some current zinc countertops) is solid zinc through and through, whereas galvanized sheet is steel sheet metal that has been dipped in molten zinc. Galvanized metal is sometimes subsequently dipped into a very dilute solution of chromic acid and, although the amount of hexavalent chrome that is possibly on the surface is very very minimal, I don't think we should design any hexavalent chrome into a surface that could have food on it. The same with the very minimal amounts of lead and cadmium that may be in galvanized sheeting. Further, I don't think that that bright spangled look will last very long with detergent washing, food spills, etc. While I believe galvanize.org to be an honorable organization, remember that they are a trade group to promote the use of galvanized materials. I certainly don't believe they would deliberately conceal serious hazards, but they are not the place to get neutral, balanced opinions comparing one material to another either.

Although it's a matter of taste -- with so many other choices available, from butcherblock to Corian to granite to porcelain tile to Formica to solid zinc to stainless steel -- I wouldn't install galvanized countertops.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


April 14, 2010

Thanks so much for your response! This is actually for a kitchen table, not the countertops. This was a wood table we had made that was done wrong and it's really messed up. Rather than buying a new table (since we're $900 in for a really bad custom table), we're trying to come up with an inexpensive and contemporary style solution. It has to be a custom table b/c of it's size - 55" x 36", so we don't want to go through that again. I wasn't really wanting stainless b/c ALL of our appliances and hood are stainless and it seems like it'd be overkill.

The solid zinc -- is that something that can cover the current wood top? I looked into tiles, but when I priced out tiles I liked, it was going to cost another $500 if I did the work myself and then I didn't have a solution for an edge, so would have to hire someone to add an edge to the sides. If we're going to put more money into this table, whatever we do needs to look really great!

Thanks again so much for your time on this.

Laura Glcy
- Marietta, Georgia


April 15, 2010

The solid zinc comes in sheets like the galvanized, but isn't as easy to find because it doesn't have as much general utility as galvanized sheet; and I'd guess that it's more expensive.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey

Zinc Sheet


April 15, 2010

Once again, Ted, - thank you! The guy that will hopefully help me do this top mentioned a mill-finish stainless also known as 2B. Any feedback on that? He's never worked with zinc, so I don't know if there is a difference in working with the different metals and a concern for how it'll come out.

Laura Glcy
- Marietta, Georgia, USA


April 26, 2010

I was thinking of using galvanized horse tanks for raised bed food gardening - should I be concerned about the safety of the food. (Haven't bought the tanks yet.)

Elizabeth Kimball
- Omaha, Nebraska, USA


June 23, 2010

I picked up a citrus juicer at a yard sale, the kind with a lever press. It appears to be galvanized steel, so I'm wondering if there is a way to paint or enamel it and avoid death by zinc poisoning?

Sarah Smith
- Atlanta, Georgia, USA


June 24, 2010

Hi, Sarah. " . . . and avoid death by zinc poisoning?" What?!

Get a grip, Sarah. There is some question of whether zinc is fully appropriate for certain applications. But death by citrus juicer? C'mon :-)

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


June 30, 2010

I'm curious about your statements that galvanized steel is not OK for food contact, because when I buy canned pineapple or mandarin oranges the inside of the can is mottled as if it is galvanized. Is this something other than galvanized metal? If not, are there some types of galvanized steel that are OK for food handling?

I'm also interested in using galvanized steel for projects involving cooking. Can you tell me the temperature at which the zinc starts to put gases into the air, or are there too many variables for that?


Thanks for all your responses, I've learned a lot from reading them!

Jim Tiffany
- Tempe, Arizona, USA



Hi,Jim.

I think you'll find that the pineapple and mandarin orange cans are actually tin plated rather than zinc plated. I'm not actually sure why they have that mottled look, but I'd guess that the tinning is done by hot dipping, similar to zinc galvanizing, and the crystal pattern arises during the cooling.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


July 8, 2010

To add to the other person's question about galvanized livestock tubs being used as raised vegetable planters:
I, too, am wondering of any possible toxins leaching into the soil/vegetables. One online landscaper suggests prepping the tub by painting its interior with asphalt paint. But am I trading one set of toxins for another? (i.e. what chemicals might leach from the asphalt paint?) I thought the galvanized tub idea was the ticket over wood raised beds lined with rot-proof bituthene roofing material. There again,I couldn't find anything concrete about bituthene dangers in that application.
Any feedback is surely appreciated as to possible food contamination.

Gail Bert
- Chico, California, USA


September 14, 2010

I have several (12) bee hives and I have been made a fantastic galvanised un-capping tray.
Its a flat pan that fits with in another that's filled with water (a bain marie) The idea is that you cut the comb from the frames and it melts inside the one container, heated by the water in the primary pan.
Essentially it all melts into an inner pan without being contaminated by water.
We will be using the pan in the stove on a direct heat to boil the water.
I wonder if I need to throw the uncapping try out. I've not used it as someone said it was dangerous to use.
Will the heat from a stove cause problems? Can I use it at all?

Shirley Cawt
- Worcester - United Kingdom

September 27, 2010

Okay, same old question basically, but last week my husband and I made a small fire in what I'm guess is a galvanized wash tub. (I bought it at a yard sale years ago and thought we would use it for a fire pit)

We cooked hot dogs on a stick and marshmallows for ourselves and our son.

I'd say the fire didn't burn for over 30 mins. The bottom of the wash tub is black from it.

Did we do harm?

Amy Gramels
- Jasper, Indiana

October 4, 2010

Hi, Amy. I don't think you will find any authoritative studies, and will have to rely on guesses, pragmatism, and analogy. So until someone finds or does an authoritative study, my feeling is that what you did is completely harmless. Zinc is an essential nutrient, not a poison.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


October 4, 2010

Please help me. We have a large group of people that want to build Rocket Stoves for emergency preparedness as seen in the video at www.rocketstove.org

After building a prototype for about $15, we found a note that we should not used the galvanized steel piping as seen in the video, but rather black stove pipe as the galvanized pipe can release toxins while heating up. Black stove pipe will double the cost and I am trying to find out if it is worth it--Does anyone know if the toxins are serious or an overreaction? I want to be safe, but cost is an important factor with this group. Can anyone advise me? I would greatly appreciate your help!

Shawnie Sutorius
- Pocatello, Idaho USA

October 4, 2010

Hi, Shawnie. You should try to track down who authored that revision note and find out their reasons and their evidence. Asking someone to challenge an opinion written by an unknown person based on unknown evidence is tricky :-)

But I have seen it written myself at http://www.woodheat.org/safety/rulesforfluepipes.htm: "Galvanized flue pipes must not be used because the coatings vaporize at high temperatures and release dangerous gases". I have also heard that the manufacturers don't recommend galvanized flues for solid fuel appliances (they can probably get very hot in a chimney fire, which wouldn't apply to gas appliances. And, since the black is more costly, it is thicker? But if it proves impossible to source anyone who really has done exposure studies, they are probably reasonably safe for wood appliance chimneys from a zinc exposure standpoint. I certainly wouldn't try to save $15 this way on a wood stove installation in the suburbs, but when your choice is two families with galvanized flues vs. one family with a stove and one without, it's the humanitarian choice.

Regards,

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Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


November 3, 2010

I am currently building a smoker out of a freezer that has a aluminum insert. my question is I have some what appears to be galvanized pieces that would be perfect supports for my stainless steel racks. it will be operating about 225 deg will it be safe to use? no food will be placed on the galvanized.

Nate Roberts
Idaho Falls, Idaho


November 3, 2010

Hi, Nate. As mentioned several times, there are few facts on this subject, only personal perspectives. But I can't see any harm from zinc at 225 deg. F with no food contact.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


December 9, 2010

Hello, I wanted to run ductwork past the upper mouth of a fireplace, heating the air that passes through it. Should I be concerned about toxic fumes being released, or will the exposure from the fireplace not be hot enough?

Thank you,
Mark

Mark Ammons
- Leesburg, Virginia USA


December 9, 2010

Hi, Mark.

Again, we're on the lookout for, but not finding, authoritative sources for such information. So, instead, all you are getting is one person's best guess. My opinion is that if this ductwork is outside of the chimney, where a mantle would be, there is little problem.

But if the ductwork actually passes through the chimney, exposed to hot exhaust gases from the fire, there is a chance of spreading poisonous carbon monoxide, and soot & creosote, and (in the event of a chimney fire) maybe even flame through the ducts. I would not rely on standard light-gauge ductwork for such an application, but only a carefully engineered Heatilator or similar design.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


December 27, 2010

hi there, I am designing wall protection for a woodburning stove installed on a corner hearth in my living room. the stove was professionally installed to the manufacturers specifications, however, my living room walls are heating up to over 211 degrees F (measured with a laser thermometer). not good, so now we are applying wall protection.

i love old rusty metal and would like to use panels made of old corrugated metal roofing to protect the walls. these would likely be installed with a sheet of durock (cement board) behind them, over a one inch airspace. the stove is designed to operate at temperatures between 450 and 700 degrees. the wall protection will reach at least 211 degree F and more if the stove is run at higher temperatures for longer periods of time.

should I be concerned about toxic fumes in my living room from residual galvanization on old rusty roofing? or if the surface is sufficiently rusty, does that indicate that the galvanization is gone? what temperature range is required for fumes to be generated from heating galvanized surfaces?

thanks for your expert opinion, happy new year!

maryloudeleted
- butte Montana

December 27, 2010

Heh Heh Hello Marylou (showing my age)

To my knowledge the only people ever known to get metal fume fever are welders, due both to the high temperatures of welding (above the vaporization temperature of zinc) and the intimate and prolonged exposure to the fumes. The surface of your stove itself probably never gets hot enough to melt zinc, let alone vaporize it. A wall protector of galvanized material would, in my opinion, be harmless. Examine your wood stove's ash tray: my Jotul ash tray appears to be galvanized and the coating is not melting off.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


March 5, 2011


Zinc, Lead & chromium is poisonous in nature and with heating of these products there will be emission of toxic gases which shall enter our food chain.

there are other alternative products..

Aluminized Steel-
Stainless Steel
Aluminium.

Now galvanized steel is fully replaced by Aluminized steel in Bakery moulds, bakery ovens, grills and barbeques.

hope this upload is useful for you guys,

Anil Chandan
- Mumbai India

March 7, 2011

Hi, Anil.

Yes, lead is poisonous.

Chrome is poisonous only in hexavalent form; in trivalent form it is an essential nutrient that we normally don't get enough of ["Chromium is an essential nutrient required for sugar and fat metabolism. Normal dietary intake of Cr for humans is suboptimal." --nih.gov].

Zinc is certainly NOT poisonous; rather, it is an essential nutrient ["Zinc is an essential mineral that is naturally present in some foods, added to others, and available as a dietary supplement" -- nih.gov]. Let's not confuse metal fume fever, a problem experienced by welders who inhale clouds of vaporized zinc because welding temperatures exceed the vaporization point of zinc (1665° F) with day-to-day usage. That's like saying no one should ever take an aspirin because eating a bottle of 300 tablets can kill people.

Aluminum can certainly be better than zinc for certain applications, and less satisfactory than zinc for others. I think that substituting scare tactics for careful engineering evaluation is the wrong approach . . . and since zinc is an essential nutrient, whereas aluminum has absolutely no place in the human body, that tack may backfire on you :-)

Thanks and Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


April 30, 2011

Is it safe to use a galvanized strip to replace a rack holder in a dishwasher? Thanks for any help you can provide.

Katy McKean
- Salt Lake City Utah USA

May 2, 2011

Hi, Katy. I think it's safe enough, but that it won't hold up well in the highly alkaline environment of a dishwasher. Stainless steel would be a lot better, and you should be able to find some on line if not in a local hardware store. Good luck.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey

Stainless Sheet


May 19, 2011

I have another question about galvanized steel. I have made swizzle sticks from galvanized steel wire. Does this mean that my guests and I are consuming harmful amounts of poison?

cindy kerr
hobbyist - columbia, Missouri

May 22, 2011

Hi, Cindy.

You are almost surely not consuming harmful amounts from a little swizzle stick, but food service items should not be made of galvanized metal. I'd suggest a redesign with stainless steel wire.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


June 7, 2011

I really appreciate how everyone's trying to differentiate between the scare and the true knowledge in this loong thread here. I specially salute Mr. Knowledge for sharing his wealth. Thank you. I tried to find the answer for my question in ALL the threads but could not find the exact one except that "don't worry about little things just enjoy life!" I intend to use stainless steel 18 gauge plate in my gas BBQ grill instead of grate, and cook on top of it directly. Should I worry about any carcinogen activity?

Iqbal Syed
- Levittown, New York

June 8, 2011

Hi, Iqbal.

Stainless steel is considered by most people to be one of the safest of all materials for food service. Pots, pans, flatware, (and often scalpels and implants) are made of stainless steel. No worries.

Regards,

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Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


June 22, 2011

I have heard of the garbage pail picnic. a 20 gal galvanized garbage pail is purchased and food is layered inside, from chicken to cabbage and cooked with lid on tight for 1 hr over hot flames. Is this harmful to the food? I have seen it done before and the people were eating and enjoying the food. But I don't want to do it if I could be causing harm to my guests. Thanks for any advice given.

ruth perry
- success missouri usa

September 30, 2011

Some of the questions here ask about heating /burning galvanized steel and the fumes. I think it was mentioned that no one died of it. Read this (http://www.anvilfire.com/iForge/tutor.php?lesson=safety3/demo) - Someone did die heating up galvanised pipes in a furnace.

I had some baffles in a woodburner and got them galvanised. They are in the flame and the fumes go out of the chimney, so no immediate risk to me I assume. Now they are chalky yellow. Don't know if they are now toxic to touch etc. and if I should get the galvanising removed, or just burn off the rest and let the fumes go out of the chimney which is 50 feet up in the air.

Mike Williams
- Conwy, North Wales

October 2011

Hi Mike. Thanks.

I don't see a claim on this particular thread that no one has ever died from zinc fumes, but this is a big site with more than 50,000 threads and it is possible that such a claim was made. I'm very much on the fence on this subject because it's possible that no one has died on the spot, but if someone dies from pneumonia and the pneumonia probably occurred because of zinc exposure, then I'd call the zinc exposure the cause of death.

I've seen this Paw-Paw story before and appreciate you publicizing it. But I would be more comfortable with it if there was a medical examiner's report or something from a medical authority or police authority rather than just guesses from friends. Since no crime was involved, though, that probably won't happen. I suffer from emphysema myself, which I blame on smoking (I never did metalwork), and I have to be careful of pneumonia too. But any air contaminant at all can be a problem; someone blowing out the candles on a birthday cake can be intolerable, for example. I do not dismiss the possibility that zinc fumes were the culprit in the death you mention, it's just that when you have emphysema, which makes you very prone to easily contracting a fatal pneumonia, it is complicated to try to blame the pneumonia on any one particular thing without solid evidence. Thanks again.

Regards,

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Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


October 3, 2011

This thread is so funny and useful. I applaud your patience. It's slightly reassuring that there are so many people so very worried about galvanized metal. Surprisingly, I still have a question.

I am not worried about toxicity as much as potential explosiveness. I am working on a sculpture using a variety of black steel fittings and galvanized pipe fittings to create an armature for the sculpture. This will then be wrapped thickly in crunched up aluminum foil and finally covered in a non-toxic clay (about 1/4" thick) which will then (hopefully) be fired in the kitchen oven at 275 degrees for more than hour.

Here's my concern: Is there any chance that the galvanized fittings will give off any kind of fumes at this low temperature that would cause any kind of explosion hazard in my kitchen oven or build up inside the foil/clay covering that would then cause any kind of explosion hazard? I am not planning to eat the sculpture. ;-) Thanks!

Jill Ann
- Central California

October 4, 2011

Hi, Jill Ann.

This is way below the melting point, let alone vaporization point, of zinc and should pose no problems. However, be careful that there are no "sealed" fittings, as the vaporization point (boiling point) of water is 212 F, and water sealed inside something can certainly explode. But kitchen ovens should be reserved solely for food service; that's harsh I know, but it's just not a good idea to try to decide which facets of what hobbies and home & auto repairs can be pushed how far in your food oven :-)

Regards,

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Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


November 7, 2011

I am using a 20 gallon trash can as a container for my rocket stove. I lined it with cement/vermiculite, so I don't worry about the can's exterior. My concern is the galvanized lid if I use it for baking.
I read in the thread about the galvanizing flaking off because the two metals heat at different temperatures. Can I cause this to happen on purpose and then repaint it with high temperature spray paint?

Rodney Brooks
- Pendleton, South Carolina

November 8, 2011

Hi, Rodney.

If practical, I'd sandblast the galvanizing off. If not, you can remove it with muriatic acid (although this is a dangerous material, and a job for people familiar with using acids for metal treatment). But I'm not familiar with the zinc flaking off anyway, and am not convinced that it will happen.

Regards,

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Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


January 14, 2012

I have been reading the various questions and responses and I'm still not certain of the answers. I am currently receiving scrap metal from a furnace/ac company. It is the scrap metal left from installing ducts, etc. It is galvanized steel. Here are my questions. I want to anneal this metal to make jewelry out of the metal. How safe is this for me to put a torch on this metal? How about putting it in a kiln. What is going to happen to the coating? Will the steel no longer be galvanized and now be more susceptible to rusting? How about buffing or texturizing the surface any problems with that? I have lots of ideas, but I want to know the dangers if any and how to protect myself if necessary. Anxiously waiting for your reply so I can create. Thank you so much. I have enjoyed this site very much.

Dianne Ziegler
- South Bend, Indiana, USA


February 15, 2012

Hi Dianne. If you can sand the zinc off, that would be okay. But if that's not practical, the kiln sounds okay to me as long as you're not breathing the vapors. Zinc is an essential nutrient, not a toxin. The zinc issue is not exposure, it's overexposure. Using a welding torch may lead to overexposure; electric arc welding certainly does. But galvanized metal may have a very small amount of chromium on it as well, and a small percentage of lead in it. These are toxins.

Once the galvanizing is gone the steel is very subject to corrosion, although a good clearcoat will offer some protection. Good luck.

Regards,

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Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


February 15, 2012

Q. Hi Jeff

I have recently built a spit braai (BBQ) out of a 200 liter oil drum.Its main feature is for roasting pigs and is gas fired with the exception of a stainless steel tray insert for placing coals used for the smoking process.It also has a temperature gauge which reads around
250° C when fired up to its max off a 10 000 BTU gas burner. Can this practice be considered safe? Please assist as I was thinking about galvanizing the drum.

Thank You

Jonathan Cain
plumber - Durban,Kwa-Zulu Natal, South Africa

February 15, 2012

Hi Jonathan. I suggest high-temperature paint (stove paint. BBQ paint) rather than galvanizing. For a really fine approach, porcelainizing would be even better if you have a facility that can do it for a practical cost.

Regards,

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Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


March 1, 2012

Q. Hi! My name is Richard. My concern is that I'm building a pig rotisserie; and is it safe that my cover to both sides are galvanized sheet metal? It's not really touching the fire, just a cover to make like a box. Does the galvanized sheet metal contaminate the food in the center?
than you very much.

Richard Goma
- Chicago, Illinois, USA

April 21, 2012

Q. Hello Ted,

I too am very grateful to you for answering almost all the questions in this thread. I haven't seen this one:
I have a "Fort Wayne, Indiana Griscer" Meat/Vegetable Grinder, a beautiful piece of Americana and a fantastic kitchen tool. Here is exactly what I have:

21703-2

I can't find anything re/ its material, but it seems to be galvanized over a very sturdy steel one-piece base. The interchangeable grinding 'cups' (the parts that mostly touch the raw food) are mottled from long wear, basically silvery-gray flecked with darker gray--more mottled than in the picture. The inside of the main part is pebbly and pocked on a very small scale. Given the pressure at which food is ground and squeezed through there, I wonder if I should stop using this.

Do you think that eating carrots or similar vegetables (not tomatoes bc of the acid, but onions--?)grated in it more or less daily is anything to worry about? If a guest is pregnant should I take care not to use it? I love using solid old tools, so I'll really appreciate your view.

Many thanks

Deb

Deb Maier
- Hastings on Hudson, New York, USA


April 23, 2012

A. Hi Deb.

Actually, this is supposed to be a public back-and-forth rather than a thread where I answer questions -- because that implies an expertise that I certainly don't claim to have :-(

Please check your grinder with a magnet to see if it is iron/steel -- I'd like to know. If so, it looks to me like it is tin plated, which would be a 100% safe coating. Hopefully someone is familiar with these antiques and will know.

Regards,

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Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


August 27, 2012

Q. I have a BBQ pit that uses a galvanized sheet metal pan to hold the charcoal. I noticed several people asked the same question but I never saw an answer. Is it safe or would it be safe if you lined the pan with aluminum foil?

Kirk Glenn
- rancho santa margarita ,ca,usa


August 27, 2012

A. Hi Kirk. I offered my own personal opinion on that a while back: I think it's safe. The problem is who can answer? The manufacturers think it's safe; the government doesn't think it's so obviously unsafe that they've banned it. But there will probably never ever be the kind of tests that would be needed to conclusively prove that it's absolutely safe, or for that matter that plain steel, stainless steel, aluminum or anything else is any safer.

Regards,

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Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


February 14, 2013

Q. I purchased a tea strainer from a Dollar General thinking it was stainless steel, like several I've purchased in the past. I brought it home, cleaned it, and began straining my lemon juice, apple cider vinegar, garlic, ginger, and herbal formula. It began to blacken after about 20 minutes of use. Why and is my formula poisoned?

Linda Parker
- Clarkston, Georgia, USA


February 14, 2013

A. Hi Linda. Your formula isn't poisoned, although I'm not quite sure why acids turned the strainer black. I'd guess that the strainer may be aluminum? Aluminum can turn black from the strong alkalis in dishwasher detergent. Is it possible that you cleaned it in the dishwasher and didn't notice that it had turned black . Acids like lemon juice and vinegar can perhaps also turn aluminum black, although I haven't ever noticed it. It's possible, I suppose, that the strainer was tin plated (which is a very foodsafe material), but if it came with no information at all, I'm just guessing and educated guesses aren't very reassuring.

Regards,

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Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


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