Cast Iron cookware discussion

[Percival]

We started a discussion in another thread about CAST IRON cookware, which I know a bit about as a user and collector and it was suggested that we make a thread here about it so here is what has been discussed this far:





I found an old griswold frying pan in the beach shack I bought awhile back.
Bought it furnished. I haven't used it because i remember hearing it needed to be "seasoned" and I haven't gotten around to figuring it out. I didn't want to wreck it.
Any info wwould be appreciated.

ST


ME:


Its simple. First that Griswold you have is the best cast iron ever produced. Its extremely collectable because when the old man who made them died they stopped making them, it was a small family in Erie, PA and when he died that was pretty much the end of it and he had a way of making the cast iron that he never shared with anyone else, the cooking surface on the Griswold is superior to anything else you can buy.


All you need to do is SCRUB it down real good with soap, water and steel wool or a green scrub pad. THEN take some BACON GREASE, bacon grease is the BEST or CRISCO LARD or any kind of cooking grease and LIBERALLY put it all over the pan real thick and heavy then put the pan in your oven BROIL it on HIGH for about 3 to 4 hours. When it is done it will be seasoned which basically means it will be pretty close to NON STICK. To keep it that way, NEVER use SOAP and WATER ON IT again, when you are done cooking simply wipe it with a real DAMP RAG and then use olive oil or any kind of cooking oil and spread it around on the pan to prevent RUST and store it away. You should use its, they are healthy and much better than the crappy sh*t you buy in the stores.




Thanks for this info, percival. My wife is always buying the no-stick Chinese made garbage, and I've heard that Teflon is very poisonous. Can I find one of these cast iron frying pans you speak of on Ebay?




ME:

Sure E bay will have a lot of Griswolds or Wagners for sale, those are the best two and they dont make either anymore so they may cost you a bit, a Giswold basic pan maybe 100 or less a Wagner around 50. You can go to a CAMPING STORE and buy a LODGE for about 30, Lodge is good and will do the same for you a Griswold will and wil last forever but a Griswold and to some extent a Wagner, has a very specail very smooth and unmatched cooking surface, although like I said, with modern technology, which they didn't have when those were made, the Lodge cast iron brand sold in stores today is pretty good, you wont go wrong with it. IF you do get a Griswold and invest in a good one try and find a nice frying pan with a LID, the lids are HARD TO FIND so if you see one with a lid for a good price its def an INVESTMENT a very collectable item. I find Griswolds often at YARD SALES for 10 bucks they dont know what the hell they have. Sometimes you will stumble on one there or at he THRIFT STORES.


DEF stay away from Teflon that stuff is toxic as hell and you do consume the sh*t over time. And you have to replace them all the time, one cast iron will last you the rest of your life and your kids life and their kids.

The wifey may complain that they are HEAVY but you cant have your cake and eat it to, in the long run you save money since you replace those cheap teflons every few months and if you dont then youre eating that chemical coating on there and that's not good.

My advice is to invest in a good cast iron frying pan, a big one, and then get a cast iron POT for cooking stews and things like that. Those two pieces and youre all set, woint ever have to buy cookware again. Just clean and store like I said above and they will be fine, important to LIGHTLY OIL all SURFACES after wiping down with damp cloth after cooking before storing as this wil prevent rust and keep it seasoned as it sits until next use.

[saint]

Thanks for the info.

I have a big old skillet but alas no lid.
Still - not bad for free.

Can't wait to try it out after I season it.


ST

[agmom]

Cool!

I only have a few cast iron skillets and a flat griddle pan.
What is the best way to re-season them when they aren't doing the "non-stick" as well as they used to?


If the pan is basically clean, but just sticking too much - follow Percival's advice, and cook a bunch of bacon. It is the simplest and best way to season the inside of the pan. You might need to do it a couple of times, and the seasoning will build up.

If it's an old cast iron pan, and needs a more serious cleaning - I've found the best thing to do is to run it through the self cleaning cycle in the oven. Only do this if it has years worth of lumpy, baked on crud - the way you often find them at garage sales, or even antique stores. It burns the crud right off, and then you just reseason it.

[Celtic Rogue]

I have a set of 5 Wagners that my parents got when they were married back in 1940. Thousand of meals have been prepared in them and I use them every day and would never use a teflon anything.

Once you have them seasoned not much will stick to them. I plan on giving them to our son too... They have been in service for 70 years and they are better now than when they were new! :)

[Osaka]

Anyone have any experience using a cast iron waffle press? Like this one

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120553161123

[uranian]

having used a cast iron frying pan for a few years now, they are easy to use even for the lazy. i can't remember last time we seasoned it, and i do give it the odd scrub with water, yet it's still perfectly usable.

a bit on teflon (http://tuberose.com/Teflon.html), too:


Environmental Working Group reviewed 16 peer-reviewed studies detailing experiments conducted over the past 50 years, showing that heated Teflon decomposes to 15 types of toxic gases and particles. Many of these studies were conducted by DuPont's own scientists, who began studying heated Teflon (PTFE) in the 1950s when DuPont workers were developing polymer fume fever that the company found could lead to a potentially fatal condition called pulmonary edema. Since DuPont's discovery of polymer fume fever, cases have been reported in the peer-reviewed literature of the same illness stemming from home kitchen exposures.

Teflon off-gasing studies show that at the design temperatures of conventional kitchen appliances, Teflon chemicals break apart to form the following particulates and gases:

Two chemicals linked to cancer or tumors in laboratory studies (PFOA and TFE); Two chemicals that are potent global warming gases (PFB and CF4); Two chemical warfare agents (PFIB and MFA) and a chemical analog of WWII nerve gas phosgene (COF2); At least two chemicals that have widely contaminated the world (PFOA and TFA), one currently undergoing a rigorous safety review at the Environmental Protection Agency (PFOA); Four gaseous chemicals and some components of the particulate matter that are highly persistent environmental pollutants, that likely never break down in the environment (TFA, PFOA, CF4, PFB, and the perfluorinated particulate alkanes); and four chemicals that are considered highly toxic relative to most other industrial chemicals (PFIB, MFA, COF2, HF).

[Desolation LineTrimmer]

I don't use anything but cast iron skillets. I have 3 of them, as well as a dutch oven. The method I use for cleaning is very easy. Using a wooden spatula I take it while still hot from cooking and put it under the hot water of the sink and scrub it. Normally with most skillets you can't do that because of the potential for warpage, but this isn't a concern with heavy cast iron. After I have cleaned it well I put it back on the flame and dry with a paper towel. I use the same paper towel over and over again. I don't bother oiling it afterwards.

[crazychicken]

Anyone have any experience using a cast iron waffle press? Like this one

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120553161123


We regulary use two of them.

A whole different method of making waffles. Use extra oil in your waffle recipe.

They make a great waffle once you get the hang of it.

CC

[Becks1516]

Thank you Percival, for sharing that info
accordingly I will effect a +1 on your Karmic Load
as an attempt to lessen whatever Samsara may be playing upon you.

[skid]

We have several cast iron with enamel coating pots and pans. They work well, but the wife complains that they are too heavy. We have Le Crueset and a Chinese knockoff that is just as good a quality.

[jetgraphics]

We have a nice family: 3 skillets (baby, mama, daddy size); 1 round griddle (great for pizza crust) ; and a 14" wok (No, I do not flip food in it! It would break my wrist.). Looking to get a porcelain lined cast iron dutch oven for those times when you want to cook acid foods that would tear up the seasoning.

America's Test Kitchen suggested the Tramontina http://www.walmart.com/catalog/product.do?product_id=11989387 (http://www.walmart.com/catalog/product.do?product_id=11989387)($39) at Wally Martski, as a good buy. (But replace the lid's plastic knob with a metal one from a hardware store or Home Depot.)

[CrufflerJJ]

having used a cast iron frying pan for a few years now, they are easy to use even for the lazy. i can't remember last time we seasoned it, and i do give it the odd scrub with water, yet it's still perfectly usable.

a bit on teflon (http://tuberose.com/Teflon.html), too:


Environmental Working Group reviewed 16 peer-reviewed studies detailing experiments conducted over the past 50 years, showing that heated Teflon decomposes to 15 types of toxic gases and particles. Many of these studies were conducted by DuPont's own scientists, who began studying heated Teflon (PTFE) in the 1950s when DuPont workers were developing polymer fume fever that the company found could lead to a potentially fatal condition called pulmonary edema. Since DuPont's discovery of polymer fume fever, cases have been reported in the peer-reviewed literature of the same illness stemming from home kitchen exposures.

Teflon off-gasing studies show that at the design temperatures of conventional kitchen appliances, Teflon chemicals break apart to form the following particulates and gases:

Two chemicals linked to cancer or tumors in laboratory studies (PFOA and TFE); Two chemicals that are potent global warming gases (PFB and CF4); Two chemical warfare agents (PFIB and MFA) and a chemical analog of WWII nerve gas phosgene (COF2); At least two chemicals that have widely contaminated the world (PFOA and TFA), one currently undergoing a rigorous safety review at the Environmental Protection Agency (PFOA); Four gaseous chemicals and some components of the particulate matter that are highly persistent environmental pollutants, that likely never break down in the environment (TFA, PFOA, CF4, PFB, and the perfluorinated particulate alkanes); and four chemicals that are considered highly toxic relative to most other industrial chemicals (PFIB, MFA, COF2, HF).


Cast iron is quite useful, and I like using it for my Dutch Oven and for corn bread.

The link referred to in your post claims that Teflon breaks down into a "chemical analog of WWII nerve gas phosgene". Phosgene was not a nerve agent - it was a chlorinated "choking" gas, resulting in pulmonary edema (fluid building up in the lungs). Minor detail, I know, but when I see stuff like this, I wonder about the validity of claims made in the rest of the (inflammatory) referenced article.

Now if I could just keep my darling wife from overheating my favorite non-stick skillets (used for making scrambled eggs among other things). Her technique seems to include setting the electric burner on HIGH, placing the skillet on the burner, then prepping all the stuff she intends to add to the skillet. I feel sorry for the coating!

[CrufflerJJ]

America's Test Kitchen suggested the Tramontina http://www.walmart.com/catalog/product.do?product_id=11989387 (http://www.walmart.com/catalog/product.do?product_id=11989387)($39) at Wally Martski, as a good buy. (But replace the lid's plastic knob with a metal one from a hardware store or Home Depot.)


Thanks for the link to the Tramontina dutch oven. What's the benefit to an enamel coated dutch oven, versus the regular cast iron version? I can see how it might be better for acidic (tomato-based) foods, but other than that......???

[Sock Puppy]

I have a number of these skillets. I can't seem to pass them by at garage sales for $3 or whatever. Sometimes I will pay up to $10 for a dutch oven with a cast lid.

Some were sold with glass lids, so the cast lids are a little more scarce.

Anyway, I think Griswold merged into Wagner at one point. I think I have one pan with both the Griswold AND the Wagner names on it.

My wife never used them before she met me, but now she loves them.

One thing to remember that hasn't been said yet--DON'T use dishwashing soap on them! That ruins the finish (on the seasoned ones, anyway). Just clean them with water and elbow grease and dry with a paper towel. They last forever. I have a fairly full set of them from my parent's and grandparent's estates.


I boutht a special square one from an antique store for $35. That is the most I've paid.

Griswold is the best in my book by far.

--Sp

[Percival]

This is a repost of a thread I did on another preparedness forum concerning dutch oven cooking. The beauty of DO cooking is that you can use either charcoal or wood. And cast iron, if taken care of, will last a long time and is very tolerant of abuse. I had to reduce the number of pictures because I'm limited to 8 pictures right now. So I had to do a little editing. Anyway here you go:

While Dutch oven cooking isn’t an overwhelming challenge, you do need to keep in mind that there is a learning curve associated with learning to cook in this manner. The first thing you need to realize is that your first couple of attempts at cooking something in your DO will be less than stellar. Relax, grab a beer and deal with it because most everybody else has gone down that path and ended up ordering an emergency pizza. Keep in mind that it takes some trial and error to find what works with your particular oven.

The first thing you’re going to need is a Dutch oven. Right now I’ve got a 8 inch, 10 and 12 inch, 16 inch and huge custom made 24 inch DO. I use my 10 inch DO about as much as my 12 and I have found that for just me and my wife the 10 inch is sized about right. However, if I could have only one Dutch oven, or had to recommend a first DO I’d definitely recommend a 12 or 16 inch inch.

http://i241.photobucket.com/albums/ff304/jerrwhy/10and12.jpg



Most recipes that you’ll come across for a DO cooking are intended for a 12 inch DO.
I think that the 12 inch DO tends to be a little more forgiving when it comes to burning foods because it’s not only bigger, but the legs are taller when lessens the likelihood of scorching on the bottom. In addition a regular cake mix will fit nicely in a 12 inch DO.
You can also flip the lid upside down and use it as a skillet.

In addition to a DO you’re also going to need a few additional pieces of equipment such as:

Charcoal starter
Lid Lifter
Tongs – to move hot coals

http://i241.photobucket.com/albums/ff304/jerrwhy/necessities.jpg



Some nice to have but not necessary pieces of equipment are:

Lid Stand
Welding Gloves
Beer


http://i241.photobucket.com/albums/ff304/jerrwhy/options.jpg


Lastly you’ll need a place or spot to cook on where the hot coals won’t damage anything. Some people use fancy tables, or some type of makeshift affair. Personally, I took 6 bricks and put them on the ground and made a square, I then took a 5 dollar piece of sheet metal from the hardware store and put it on top of the bricks. No more scorched grass for me.

Most people use Kingsford charcoal when they cook with their DO. Kingsford tends to be very consistent and predictable. You’ll get about an hours worth of heat out of each briquette. An 18 pound bag fits nicely in a five gallon bucket. I keep 4 buckets worth on hand at any one time. I figure this will last us 4-6 weeks in the event of an extended outage then I have to start using wood. And with several full cords of wood lying around we’ve got plenty.

How do you control the temperature of a DO? Keep in mind that most baking is done at the 350 degree range; fortunately this is easy to figure out in a Dutch oven. To accomplish this you multiply the diameter of the DO times 2 then divide by 3. You’re going to place 1/3 of the coals on the bottom, and 2/3 on the top. For example you have a 12 inch DO.

12x2= 24

Twenty four is the approximate number of coals that you’re going to need to achieve 350 degree. Next you take 24 and divide it by three.

24/ 3=8

So now you’re going to place 8 coals (1/3) on the bottom of your DO and 16 coals (2/3) on the top.

- Each additional coal will add around 15 degree of additional temperature. So if your recipe calls for a cooking temp of 400 degree then you’ll need to add three to four coals.

- Adding the coals to the top of the DO will reduce the likelihood of scorching on the bottom.

- For breads I always reduce the number of coals on the bottom by approximately 2-3. This prevents a burnt bottom.

- When you want to brown the tops of bread or rolls add a few extra coals to the top of the DO in the last few minutes of cooking.

- When your breads start to brown take them off the heat and the residual heat in the DO will continue to cook them and they won’t be over done.


When you’re ready to cook you’ll need to start your coals about 15 minutes ahead of time. You want them cherry hot just like a grill.

http://i241.photobucket.com/albums/ff304/jerrwhy/hotcoals.jpg



In this case I’m going to cook fried chicken in a 12 inch DO. While cooking fried chicken in an oven might be viewed as a moral sin by many, it’s much healthier this way as the amount of fat and cholesterol is greatly reduced. The recipe calls for this bird to be browned in a skillet and baked in an oven.


The rest go on top. This recipe calls for a temp of 375 degree, so we upped the number of coals accordingly. Cooking time took about 40 minutes. Every five minutes I rotated the oven 180 degree and rotated the lid 180 degree in the opposite direction. Rotating the DO and lid helps evenly distribute the heat.

http://i241.photobucket.com/albums/ff304/jerrwhy/top.jpg



In addition we’re having some of garlic rolls. They nestle quite nicely in my 10 inch DO.

http://i241.photobucket.com/albums/ff304/jerrwhy/nestle.jpg



I should be using 7 coals on the bottom. However, because this is bread I reduce the number of coals by 2-3 on the bottom and place them on the top I get much better results. In this case I used 5 coals, and just like the chicken I rotate the oven and lid every five minutes.

Once the rolls start to brown I take them off the heat and in this case sprinkle on some Asiago cheese, recover, remove the coals and set aside until the chicken is ready.
http://i241.photobucket.com/albums/ff304/jerrwhy/rolls.jpg



Once everything is done it’s time to eat.

http://i241.photobucket.com/albums/ff304/jerrwhy/chicken.jpg





Peace
and Enjoy

Percy

[crazychicken]

We use Dutch Ovens extensively when we are way outback at the branding and round-up camps. Lots of experience with them.

Use wood exclusively. Cottonwood and sagebrush mostly.

Both my wife and I found the charcoal info very interesting.

Percival---Good stuff.

[Percival]

We use Dutch Ovens extensively when we are way outback at the branding and round-up camps. Lots of experience with them.

Use wood exclusively. Cottonwood and sagebrush mostly.

Both my wife and I found the charcoal info very interesting.

Percival---Good stuff.


Hey CC, good to see you man. Its always nice to meet and chat with others who enjoy using the dutch oven, I grew up with them and there is nothing I enjoy more than cooking a good hearty meal in one of them.

Like you, I also enjoy using wood as my source of heat for the DO and growing up thats how dad and I always did it, we would be fishing and camping out and we would toss whatever we wanted to eat in to the DO and then toss the whole DO right in to the campfire and 30 minutes or an hour later we had us a damned good meal. But as I got older I wanted to refine my DO cooking skills and so I did a lot of experimenting and learned that with charcoal, as stated above, you can actually control the cooking heat of your DO just as much as you can control the oven in your kitchen with knobs, if you use the numbers and methods that I provided above you will be surprised just how precise you can get and that really comes in handy when making things like bread and cakes when a particular heat is required for things to come out just right. So try out the method and numbers above sometime and I think you will enjoy it and appreciate your new skills with the DO, but never give up on the wood, thats the good old fashioned way of doing it and there is nothing else quite like it!

[crazychicken]

[/quote]
Hey CC, good to see you man. Its always nice to meet and chat with others who enjoy using the dutch oven, I grew up with them and there is nothing I enjoy more than cooking a good hearty meal in one of them.

Like you, I also enjoy using wood as my source of heat for the DO and growing up thats how dad and I always did it, we would be fishing and camping out and we would toss whatever we wanted to eat in to the DO and then toss the whole DO right in to the campfire and 30 minutes or an hour later we had us a damned good meal. But as I got older I wanted to refine my DO cooking skills and so I did a lot of experimenting and learned that with charcoal, as stated above, you can actually control the cooking heat of your DO just as much as you can control the oven in your kitchen with knobs, if you use the numbers and methods that I provided above you will be surprised just how precise you can get and that really comes in handy when making things like bread and cakes when a particular heat is required for things to come out just right. So try out the method and numbers above sometime and I think you will enjoy it and appreciate your new skills with the DO, but never give up on the wood, thats the good old fashioned way of doing it and there is nothing else quite like it!
[/quote]

We are doing a gathering/sorting next weekend. Expect twenty people. I am going to try the charcoal method for a whole lot of cooking.

Looking forward to trying.

Thanks for the tips.

CC

[Percival]

Thats great to hear, just use that formula and you will be fine, those are very precise numbers that I have come to over and over and over without any problems, when I follow the directions above everything always comes out just right, the rotation and the ratio of coal on top and bottom are the keys, every added coal will add about 15 more degrees of heat.

Good luck and let me know how it goes.

[jetgraphics]

America's Test Kitchen suggested the Tramontina http://www.walmart.com/catalog/product.do?product_id=11989387 (http://www.walmart.com/catalog/product.do?product_id=11989387)($39) at Wally Martski, as a good buy. (But replace the lid's plastic knob with a metal one from a hardware store or Home Depot.)


Thanks for the link to the Tramontina dutch oven. What's the benefit to an enamel coated dutch oven, versus the regular cast iron version? I can see how it might be better for acidic (tomato-based) foods, but other than that......???

The enameled dutch oven is not to replace a conventional cast iron dutch oven - but to complement it.
In many cases, when you are making a sauce or deglazing, a conventional cast iron pan will often lose its seasoning / coating.

[jetgraphics]

Not to go too far off topic - but I wish I had known more about the basics of cookware before I wasted money on [expletive deleted] non-stick junk.
In retrospect - or if giving advice to someone furnishing their first domicile - I'd strongly suggest:
[] Cast Iron frypan 10" - 12", dutch oven, and an enameled dutch oven
[] 6 qt. stainless steel pressure cooker
[] 6 qt. st. st. stockpot, with steamer / pasta insert
Those should cover the bulk of cooking chores.
{ex. boil pasta in stock pot, make sauce in the enameled dutch oven, pressure cook soup stock, fry / sear meats}
Optional additions:
[] Cast Iron griddle, various sizes of frypans
[] St. St. sauce pans (generic) for misc. small items
[] Wok -- if one has a stove capable of providing the requisite heat intensity

[Gknowmx]

Thanks for the great thread folks. I have started to use cast iron more and more over the last couple of years. I love it. I too bought into the expensive coated crap years ago. Some great advice here.

[crazychicken]

Thats great to hear, just use that formula and you will be fine, those are very precise numbers that I have come to over and over and over without any problems, when I follow the directions above everything always comes out just right, the rotation and the ratio of coal on top and bottom are the keys, every added coal will add about 15 more degrees of heat.

Good luck and let me know how it goes.


THe food came out PERFECT. I did it with your sugestions and it could not have been better.

THANKS FOR THE STEP BY STEP INFO.

Regards,
CC

[Percival]

Glad to hear it went well CC, now you can do it whenever you want and be confident the food will come out right and tasty.

[crazychicken]

Glad to hear it went well CC, now you can do it whenever you want and be confident the food will come out right and tasty.


Thanks again,

CC

[CrufflerJJ]

I like cooking in cast iron here at home. Skillets for corn bread, dutch ovens for stews & bread.

I picked up an old dutch oven today. It's a Piqua Ware Favorite #9,and is still in great shape. See the attached picture. What's unusual about this one is the side ring, possibly to help dump the contents out while holding the bail. In doing some Googling, the manufacturer went out of business back in 1934, so this dutch oven is "just a few" years old.

I also just ordered a size #3 potjie. This is a South African 3 legged cast iron cauldron, used for cooking over coals. It's been on the "to buy" list for a while. See: http://www.taste-africa.com/product_potjie.php

[crazychicken]

cruffler33

Very nice!

CC

[Shorty Harris]

Last week I stopped by one of our local Thrift stores and found an 8in Griswold Skillet. A lil surface rust, no pitting, cracks, or any other defects. Picked it up for only 5 bux. Took it home..some light cleaning, and some seasoning with bacon grease on my outdoor grill. and all was good to go.

[crazychicken]

Last week I stopped by one of our local Thrift stores and found an 8in Griswold Skillet. A lil surface rust, no pitting, cracks, or any other defects. Picked it up for only 5 bux. Took it home..some light cleaning, and some seasoning with bacon grease on my outdoor grill. and all was good to go.


Great find.

I'm not that lucky!

Congrats.

CC

[Saul Mine]

Polytetrafluoroethylene

by Saul Mine
April 27,1999
Arizona State University


Introduction

Polytetrafluoroethylene (abbreviated PTFE, also known by the trademarks Teflon, Silverstone, T-Fal, Supra, Resistal, and others) was discovered accidentally in 1938 by Roy J. Plunkett of DuPont’s Jackson Laboratory in New Jersey. Since then, this seemingly innocuous material has quietly flooded the country. If the average person ever thinks about Teflon at all, it is to idly wonder, “How do they get it to stick to a fry pan?” But even a partial list of Teflon’s uses reveals that a vast amount of this material has been brought into the world. Common uses include:

Non-stick fry pans, cake pans, pizza pans, breadmaker pans
Deep fryers, waffle irons, griddles
Portable heaters
Irons with non-stick sole plates
Self cleaning ovens
Heat lamps
Curling irons
Hair dryers
Stovetop burners
Coffee makers
Medical implants
Prosthetic devices
High performance industrial filters
Scientific instruments
Electrical insulation

PTFE is widely used for its stability at high temperatures. Most polymers are unstable above the boiling point of water, but PTFE is stable at least to 260 C, and in some applications up to 400 C. It is used in electronic equipment for its combination of chemical resistance, heat resistance, and dielectric stability.

In all of this, there have been very few voices urging caution. A person who reads a lot might run across an occasional warning that Teflon releases poisonous gases when overheated. A few people might wonder about eating the flakes of Teflon that fall off their non-stick fry pans, but nobody ever seems to worry much about it. The purpose of this paper is to investigate those questions and others, including:

What are the hazards in the manufacture, use, and disposal of PTFE?
Is PTFE recyclable, and what are the proper disposal methods?
What are the breakdown mechanisms and resulting products of PTFE?
Are Teflon oil additives actually any good?
Is it true that PTFE kills parakeets?

Production

The manufacture of PTFE may begin in two ways. First, calcium fluoride is reacted with sulfuric acid to make hydrofluoric acid, and methane is chlorinated to make trichloromethane. Alternately, the process can be done with hydrofluoric acid and trichloromethane already procured. Then they are reacted with a catalyst of antimony trifluoride to produce chlorodifluoromethane, which forms tetrafluoroethylene (TFE) with no catalyst at 590 to 900 C. The yield is typically about 95%, which is very important in the economics of the process. TFE tends to self polymerize (that is how PTFE was discovered), but careful control is required to get it to polymerize in the desired manner. Low molecular weight PTFE is not strong enough to be a useful material. Overall, the processes are complicated and very different from the methods used for other plastics, so PTFE is significantly more expensive.

PTFE is manufactured as a raw material in the forms of resin, powder, pellets, or aqueous dispersion, and then shipped to other manufacturers who actually make it into products. The forms are chemically identical but require completely different handling methods. Each form is processed in a different manner according to very specific instructions provided by the manufacturer. Getting the world’s non-stickiest stuff to stick to a fry pan is a very good trick, and DuPont won’t say how they do it, except that a “primer” is used. The dangers in these processes come not from the PTFE, but from the other materials involved. Powder methods usually involve combustible lubricants and extrusion at high temperatures and pressures, so fire is a danger, along with any other hazards from the lubricants. Water dispersions usually require baking to dryness, with possible release of TFE gas and the various surfactants used to stabilize the dispersion. In all cases the first line of defense is ventilation, but careful design is needed to be sure the ventilation actually removes noxious products. Merely blowing a lot of air around is not sufficient.

The only danger in producing raw PTFE, other than a fire in the factory or a slippery spill, is the TFE gas, which is also the primary product released during decomposition. The combination of TFE and tobacco presents a unique and insidious hazard. It is recommended to completely ban tobacco products from the work place. This is discussed further in the section on toxicity.

Fate

The fate of PTFE is rather simple: it is very likely going to be PTFE forever. It is the least reactive material known. It is not attacked by any known acid or base or any other kind of reagent, and does not dissolve in any known solvent, although if it has voids, the voids can absorb liquids or gases. There are just two things that will break down PTFE: temperatures in excess of 260 C, and ultraviolet light. Above 400 C, finely powdered PTFE can react violently with finely powdered metals, especially aluminum and magnesium. These conditions can be easily produced by grinding or sandblasting PTFE coated products, so some caution is warranted in machine shops and reclamation operations. Another hazard is pumping aluminum flake slurries through pumps or fittings lined with PTFE. This can cause unexpected and maybe violent failures in the equipment.

PTFE does not burn, but if heated, it breaks down into sub-micron particles and several toxic gases. These products are discussed in the section on toxicity. PTFE and PTFE coated products should never be mixed with domestic or industrial waste that may be incinerated. Preferred disposal methods are recycling and landfill. Incineration is permissible only in a plant equipped to remove hydrogen fluoride and other acidic combustion gases. Liquid dispersed resins are disposed by filtering out the solids and sending them to a landfill. The water always contains TFE gas (which is water soluble), but can be adequately processed by any waste water treatment facility that is prepared and permitted to do so.

Of special interest is the use of Teflon as an additive to motor oil. This seems like a good idea, but it doesn’t work as one might expect. DuPont has never endorsed the use of PTFE for this purpose, but apparently cannot stop dealers from using the Teflon trademark as long as the product actually contains DuPont Teflon. Recall that one method used in manufacture is extrusion of PTFE dispersed in a lubricant under certain pressures and temperatures. PTFE won’t stick to anything, but it will polymerize with itself and become lodged on rough surfaces or in tight passages. This is exactly what it does in a gasoline engine. Granules of PTFE form and grow, adhering by mechanically gripping roughened surfaces inside the engine, and sometimes plugging oil passageways and clogging rings. If this happens, PTFE can actually prevent normal lubrication. This is an application that should be avoided. If the used oil is improperly discarded there is little chance of the PTFE in it being broken down or reformed. If the oil is sent to a rerefiner as it should be, the PTFE must be filtered out and sent to a recycler.

Measurement

Because of the extreme nonreactive nature of PTFE, the only practical way to measure it is to physically separate it and weigh it. When that is not possible and a precise measurement is needed, professional technicians must be hired at rates from $800 to $2000 per day, plus $25 to $150 per sample analyzed. In toxicity testing, only PTFE is used, so measurements are obtained by filtering the products out and weighing the filters. Several grades of filters are used together, since the effects depend more on the size of fume particles than on inherent toxicity. In other settings, a common approach is to analyze everything else in the system and assume that the mass not accounted for is PTFE.

Of greater concern is the presence of the monomer TFE. Small amounts of this gas are released at temperatures below the breakdown of the polymer, and increasing as the temperature rises toward 400 C. In the case of non-stick fry pans, the amount of gas released by the PTFE at usual frying temperatures is comparable to the amount of gas released by the plastic handle. Other gases are released at higher temperatures, and all these gases are easily measured with conventional instruments. In determining safety requirements for handling resins, such as in a factory, a measurement is not usually considered necessary. Instead, equipment is selected to cope with one milligram of TFE per kilogram of PTFE processed, since the solid product reliably contains very nearly that amount of the gas. It is suspected that this small amount of gas is responsible for the softening of solid PTFE at temperatures below 260 C. There is some evidence to support this, but it is not certain.

Toxicity

PTFE is not toxic at all, but when heated above 400 C it releases fumes that cause fever. This is called “polymer fume fever,” or PFF. In humans the symptoms are nearly identical to the symptoms of “welding fume fever,” and very similar to the effects from inhaling soot or other finely divided powders. The symptoms depend mainly on the particle size, which is about 0.05 micron. It is presumed that the particles are small enough to enter the alveolae and cause mechanical irritation there. Only one case of a person being killed by fluoropolymer (not necessarily PTFE) fumes has ever been reported, and that involved burning materials in a facility not equipped to handle the emissions.

Parakeets are known to be much more sensitive than humans to fume fever, and parakeet lovers are very worried about Teflon products in their homes. DuPont acknowledges that these things are true, but points out that frying with butter also releases similar amounts of toxic gases, and no bird has ever been known to die accidently from either butter or Teflon.

Researchers have also pointed out that the extreme toxicity sometimes observed in tests is only caused by pure fumes of PTFE produced by high temperatures without flaming. Mixing the polymer fumes with any other kind of fumes, such as wood smoke, greatly reduces the observed symptoms. The reasons for this are not clearly understood, but it has been confirmed. It is thought that the effect may be caused by the test apparatus, which recirculates fumes through the furnace, breaking any clumps back into fine particles.

TFE is also considered non-toxic, or at least non-carcinogenic, but causes the same PFF symptoms as PTFE particles. The TFE molecule is always smaller than the PTFE particles, so it is a more threatening nuisance. Symptoms also include choking, eye and nose irritation, mild central nervous system depression, and dry cough. Inhaling large amounts can cause cardiac arrest and death. A limit of 5 PPM in work areas has been recommended. TFE also has an annoying tendency to be absorbed by tobacco. Each cigarette in an open pack, carried for a few hours in an area where the concentration of TFE is within recommended limits, can absorb enough TFE to cause polymer fume fever when it is smoked outside the building later. This is quite remarkable but very real. Tobacco products should not be brought into the building at all. Likewise, PTFE and other fluoropolymer products should be used with great caution where tobacco products are made.

Other gases released by heating PTFE include:
1.Carbonyl fluoride -- Symptoms may include skin irritation, eye corrosion, respiratory irritation, or difficulty in breathing, and these symptoms may be delayed several hours. Immediate medical attention and/or observation may be required.
2.Hydrogen fluoride: A highly corrosive acid that can be absorbed in toxic amounts through the skin. Symptoms may be delayed. Immediate medical attention is required.
3.Perfluoroisobutylene: Symptoms in animals include wheezing, sneezing, and abnormally deep or rapid breathing. High concentrations cause pulmonary edema and death. Little is known about human exposure.
4.Carbon monoxide: High concentrations and/or long exposures cause sleepiness and possible nosebleed, followed by death.

These gases are usually only produced at temperatures well above 400 C and in the presence of water vapor. Very small quantities of these gases have been detected in finished products, apparently caused by the forming process and trapped within the plastic for a time. This illustrates the important of exactly following the manufacturer’s processing instructions. Such residual contamination can accumulate in sealed packages and closed storage areas, so packages should be opened in a ventilated area and storage rooms should be ventilated before entering them.

It is worth emphasizing that all of the dangers associated with PTFE occur almost exclusively in manufacturing or recycling operations. The danger from a piece of Teflon in any normal setting, including fumes and flakes from an aging fry pan, is zero.

Treatment and Pollution Abatement

The recommended treatment for waste PTFE is either recycling or landfill. Discarded PTFE is not a pollutant, and it is only a hazard if it is burned. The most abundant combustion product is TFE gas, which is not toxic but causes a fever when inhaled. The extreme sensitivity of some birds to TFE has been noted. At higher temperatures, PTFE also yields hydrogen fluoride, carbonyl fluoride, and a small amount of perfluoroisobutylene. Any installation that would incinerate PTFE must be prepared to remove these components from the exhaust. Modifying non-stick cookware for use in other ways should only be attempted with great caution, since such items are almost always made of aluminum, and attempts to grind or otherwise machine the combination of aluminum and PTFE can cause a fire or explosion.

Conclusions

PTFE is the safest material ever made by man. The manufacturing process is somewhat hazardous, and burning the waste is definitely hazardous, but otherwise it is totally safe, even for the extreme sensitivities of budgies. The only application found that is unsafe is as an additive in motor oil, and even then it can injure only the motor.
References

1. “Guide To The Safe Handling of Fluoropolymer Resins” 3rd Edition, 1998
Fluoropolymers Division Of The Society Of The Plastics Industry, Inc.

2. “Polytetrafluoroethylene Decomposition Products”
http://www.osha-slc.gov:80/ChemSamp_data/CH_263700.html
Occupational Safety And Health Administration, US Department Of Labor

3. ”Beaks - Teflon Kills Birds”
http://www.iserv.net/~beaks/teflon.htm
Reprinted from The Parrot Post (The Parrot Club Of Manitoba) Feb. 1994

4. “Oil And Teflon: Slick 50 And Other Teflon Additives”
http://edge.edge.net/~deschamp/teflon.html
Mike Deschamps

5. “Frequently Asked Questions About DuPont Fluoropolymers”
http://www.dupont.com/teflon/faq/index.html
DuPont Corp.

6. “Polytetrafluoroethylene”
http://www.psrc.usm.edu/macrog/ptfe.html
University of Southern Mississippi

[CrufflerJJ]

A decent source for inexpensive cast iron stuff (& propane burners) is Agri Supply (agrisupply.com). I just received my first order from them, and got a single & a triple burner, plus 2 cast iron woks. The dutch ovens I ordered are on backorder.

[Heimdhal]

We got one of the 12 inch "Lodge" skillets a few weeks ago and I love it. Ive pretty much cooked everything I needed a large pan for in it and the others ones have just sat idle.

it cleans up so easy too. I dont know why I waited so long to get one.