Junk Stainless Steel ...?

I'm noticing a substantial change regarding the cheapo stainless steel cups and water bottles I'm bringing home these days.

Used to be that when I got used stainless from a swap meet etc. I would bring it home and soak it in a strong bleach solution. This seemed prudent; you never know where it's been. The effect of the bleach on the steel itself was nil.

But I'm noticing that some of the thin Chinese-made stainless seems highly susceptible to corrosion. A bleach solution will start causing rust spots within minutes, and I have one canteen that developed a pinhole all the way through the so-called stainless steel wall.

I wonder if this is at all related to the "nickel pig iron" that China is producing to get around the price of high-grade nickel.

Anyway, heads up.

Doug, any brand names we should avoid?

I rather doubt you will see this in quality name brands. They specify the composition of their products (or they should anyway).

If it's stamped 18/8, for example, that's what it will almost certainly be. Even the cheap no-brand stuff used to be 18/8.

If it's not stamped or name-brand, though, it's buyer beware. Note that this new stuff will be usable in a lot of situations, especially for casual use; but I wonder about the effect of, say, a salt-water environment.

Chlorides, like bleach, are pretty hard on stainless steels. High concentrations, high heat, and extended exposure times can in time pit even quality 316 stainless steel.

The manner of corrosion, pit corrosion, works in a way that makes metal thickness far less of an asset than it might otherwise seem. Even steel several inches thick can develop pinholes in shockingly short amounts of time.

http://www.cip.ukcentre.com/rust2.htm

Stainless steel containers that corrode in high concentrations of warm bleach may not be otherwise vulnerable to corrosion and may not be deemed defective or substandard given that they might give acceptable service as long as they are not soaked in bleach.

The same sort of narrow vulnerability may be seen in copper dishes to food acids and aluminum pots to copper.

An old dirty trick to sabotage a aluminum boat hull used to be to flip a copper penny into the bilge. Water and galvanic corrosion can produce a penny-sized hole in a shockingly short amount of time.

Point being that the aluminum boat hull may be extremely high quality otherwise but it is a known and accepted vulnerability of the material itself.

I would suggest that you might give these presumed low quality stainless items a shot in non-critical use to see how they hold up.

Along with the cheaper mfg. of stainless steel,Is it possible that the Bleach is, More caustic than it used to be as well?I do know that Bleach&Stainless Steel,or any other steels,are not Best of friends at any time!If Blast should read this,I believe he will respond in kind as this Area is Very Familiar to him.

Bleach will cause even very high grade "stainless" to rust in under 24 hours. Stainless Steel is really a misnomer- stain resistant is more realistic. If a steel has iron in it, it will eventually oxidize. To be called stainless a steel has to contain at least 13% Chromium, and that's all the name really means.

Interesting -- I hadn't heard that one. I assume it's a salt-water reaction?




Agreed, these items still have value for casual use. I'm only paying a buck or so for them (used), so I have no major gripe. I just wanted people to be aware of an observed weakness.

there are lots of good ways to clean and/or disinfect without using high concentrations of bleach for long periods. Vinegar does a good job, as do boiling water, isopropyl alcohol, betadine, and sunshine. I admit to a tendency to drown stuff in clorox, but it is a product of the er nurse philosphy that, if one is good, four is better, and a pathogen cannot get too dead.

It sounds that you may be right that some of the lower grades of Stainless steel such as Chinese made 200 series grade are making it into supposedly food grade utensils such as cups, bottles and vacuum flasks.

Even then it is not a good idea to use Hypochlorites (Bleach) for disinfection even with 304 and 316 food grade stainless. There are other ways to clean and disinfect such as steam cleaning.

http://www.bssa.org.uk/topics.php?article=45&featured=1



http://www.bssa.org.uk/topics.php?article=91

304 is referred to as 18/10 or 18/8
430 is referred to as 18/0

The surface finish of many stainless steels also have an important function to the corrosion resistant qualities.


http://www.bssa.org.uk/cms/File/surfacefinishbssaVer2.pdf

Interesting links. Thanks!

I don't know as I would give up using chlorine bleach entirely.

I suspect that a good part of the corrosion issue comes from simple overuse. I've pitted my share of stainless steel pans and silverware using bleach too enthusiastically. It is easy to splash in some bleach and wing the concentration. The shift from 'regular' to 'ultra' bleach over the last few years has made overuse still easier.

The standard concentration of bleach to water to disinfect surfaces is one in ten. This is what is used for disinfecting surfaces contaminated by HIV, Hep-C, flu, you-name-it. Higher concentrations are Not more effective nor do they work any faster. Most people use far higher concentrations of bleach than necessary.

But remember that bleach is a good disinfectant but a lousy cleaner. For the best bacteriological safety you want to clean, scrub with soap and water to remove the bulk crud, and follow up by disinfecting with a bleach solution.

The action of copper inducing corrosion on aluminum is primarily a saltwater issue because the saltwater is both conductive and corrosive on its own but galvanic corrosion can cause some pitting of aluminum in fresh water. Same mechanism and effect but much more slowly.

In saltwater just scraping the aluminum with copper, transferring tiny bits of copper, can be enough to cause a reaction. Doing electrical work on a boat, particularly an aluminum hulled boat, it is wise to police all wire cut-offs. A lot of mechanics spread out and work on top of a piece of canvas. This keeps waste under control, and keeps dropped tools from falling into the bilge.

If the goal is an actual hole saltwater and a solid copper penny, as opposed to the more modern copper plated zinc, are the optimum ingredients for success.

If you wish to observe this effect it is simple enough to mix up some saltwater in an aluminum soda can and drop in a pre-1982, solid copper, penny. Clean the penny, slightly scratching the aluminum, and increasing the heat all speed the process. This is a fun experiment for kids.

Technically you can drop down to 11% chrome and still be considered "stainless steel". The chrome on the surface of the stainless steel item reacts instantly with any oxygen present to form chrome oxide. The chrome oxide forms a protective layer over the surface of the steel which prevents oxygen from reacting with the iron to create iron oxide aka rust.

The problem with bleach (and salt water) is that it contains chloride ions. Chlorine LOVES to react with chrome, so much that it will even tear it away from oxygen. Chloride ions yank chrome from the chrome oxide, causing holes in the protective layer and prevent a new chrome oxide layer from forming. This leaves the remaining iron unprotected and easily corroded. Even weak concentrations of bleach can cause pitting in stainless steel very quickly.

-Blast

I know bleach kills SS thermoses real fast. Usually they don't even look ruined but all it takes is one tiny pinhole on the inside and the vacuum is gone.

@chickenlittle: Good point about thermoses. I hadn't thought of that. Note to self: no bleach allowed in the Nissan.

@Art in Fl: Generally, I'm not going to give up using chlorine bleach. There are too many situations where the "big nuke" is absolutely necessary. But I'll keep a closer eye on concentration and duration. Especially important since I'm seeing household bleach with concentrations ranging from 4% - 6% on the shelf, so it's really important to do the math.

Rather than use Hypochlorites, you could sterilize the stainless steel using sodium hydroxide, i.e. a weak hot solution of caustic soda, then thoroughly clean out with hot boiling water after pouring away the caustic soda solution down the drain.

You could also give the internal stainless steel of a vacuum flask or water bottle etc a couple of blasts with a Steripen just to make sure. This will kill (deactivate) all viruses and bacteria and other nasties such as crypto etc.

...or you could expose the container to the radiation from a low yield nuclear device...with all due respect, and while I enjoy listening to the agonal screams of creatively killed bacteria as much as the next fellow, I spend most of my life eating and drinking out of vessels that have been adequately cleansed with warm soapy water, and seem none the worse for wear. The extreme sterilization methods may pose more hazard to the user's health than do the microbes in the bottle.

Cheap materials from China have been known to contain other
impurities including lead. Those switching from plastic to
metal food and water containers?
It is not called stain-proof, but stain-less.

I'm glad I didn't mention the Nitric Acid or the Iodine solution. The alkali solution such as Caustic soda is much more readily available and is a useful household chemical.

http://www.totalcleaningsupplies.co.uk/caustic-soda-granules---500g-199-p.asp

Caustic soda is no more extreme than using Bleach and is probably safer due to possible reaction with other chemicals that could free Chlorine gas (now that is pretty toxic).

The Steripen is also a quick and simple method of killing bugs rather than a chemical solution and would be a very safe way of disinfecting a water bottle or Vacuum flask without causing any chemical or corrosive actions on the Stainless steel. There is no need for radionuclide energy decontamination as this could prove to be quite dangerous and counter productive especially if your water bottle is contaminated with the Andromeda Strain

The steripen approach-bathing the inside of the bottle in synthetic sunshine-is delightful and non-toxic. I must concede that the boiling caustic soda solution would be very useful if the water bottle contained bacteria-contaminated oysters, or a small, rabid wolverine. I suppose one must identify the contaminant in order to make sense of the cleansing process.

I agree.

A simple soap and water wash and air frying covers 90% of the cleaning and disinfection needs in every day use. If there is contamination by blood or body fluids, or diseases going around disinfection with a 10% bleach solution after cleaning covers that.

Alternatives that are known to work, efficacy depends on the specifics of what is being cleaned and what it is contaminated with: laying stuff out in direct sunlight, boiling water, immersing objects in water double dosed with iodine water purification tablets, steaming, heating stuff in/near the campfire, alcohol wash, dehydration/aging.

I keep on hand a couple of bottles of the cheapest vodka I can find. Anything I'm concerned about (Camelback-type bladders in particular) get a liberal dose of the vodka to sterilize and dry them...and then I drink the vodka.

Sometimes I rinse things out 3-4 times just to be sure they are clean.

-Blast

It's entirely possible the things are made of some kind of SS that is not appropriate for the end use.

Or that the end user is unknowingly abusing it in some way.

Soaking SS in a strong bleach water solution for any length of time is a bad idea. It should not hurt it to use bleach water to rinse it out as a means of disinfection, but leaving the bleach water in contact with the SS overnight on a regular basis is a bad idea for any grade of SS. In reality you don't need a very strong solution for disinfection,it does not need to contact the surfaces for all that long, and chloride cracking is not as big a deal at low temperatures. So use your head or a different means of disinfection.

No SS is really stainless and all off them can and do corrode. They are all more resistant to corrosion than steels, to one degree or another.

It's also possible that if you are using a fairly thin SS container for heating water the repeated heating cycles are causing a problem. It expands and contracts as it is heated and cooled and if the material has impurities in it, those areas may not expand and contract at the same rate as surrounding material, leading to pinholes.

It's not unusual to find Chinese made steel that has very hard spots in an otherwise fairly soft (at least for steel) plate. It's because they don't worry too much about the steel being perfect, and a lot of their steel is mixed with whatever scrap they can get in the rest of the world and ship there. In fact, China is a huge importer of scrap steel from the US. But when they make new steel plate out of scrap, its not unusual for some hard tool steel to get mixed in and not get mixed up very well so you end up with hard spots in the plate.

If I drank Isopropyl Alcohol, it would sure clean out my
bladder!