Some time ago there was a discussion of the stainless properties of
stainless steel:

Stainless steel does well in relatively dry environments with access to
oxygen. Look at your home cutlery, for example.
Then go buy a stainless bowl and fill it half full of water.

See how long it takes to develop its first pin hole.
A matter of weeks or less, quite likely.


No, that is an exaggeration. In fact I have a stainless bucket - said
to have been made in India - that has been on the boat, and in general
use for some ten years. No holes yet.

Cheers,

Bruce in Bangkok

If you have a stainless steel bucket, then you are in a position to
do a little experiment then. One you are convinced will be harmless
even.

Half fill the bucket over the side of your boat, and leave it on deck
-
half full, untouched, unstirred. What could be easier? Let us know how
long it takes for the bucket to dry out..... (one way or another! :-)
This is not such a risky proposition for a hot galvanized bucket of
the traditional design though....


I decided to try out the suggestion and filled a stainless steel
mixing bowl (my wife's actually) with tap water, wrapping it with
saran wrap to eliminate stray air currents and prevent evaporation as
much as possible, and placing it in a spare room where it has been
stationary for two weeks.

Today I emptied the water and inspected the bowl. I poured the water
out and carefully (so as not to destroy evidence) wiped the interior
with a paper towel to dry it - the results? None. The dry bowl
evidences no marks, discoloration, nothing to indicate that it ever
had water in it.

Another urban myth destroyed.



Cheers,

Bruce in Bangkok
(bruceinbangkokatgmaildotcom)

Bruce in Bangkok wrote:
Some time ago there was a discussion of the stainless properties of
stainless steel:

***
If you have a stainless steel bucket, then you are in a position to
do a little experiment then. One you are convinced will be harmless
even.

Half fill the bucket over the side of your boat, and leave it on deck
- half full, untouched, unstirred. What could be easier?
Let us know how long it takes for the bucket to dry out.....
(one way or another! :-)*
*
*
*
I decided to try out the suggestion and filled a stainless steel
mixing bowl (my wife's actually) with tap water, wrapping it with
saran wrap to eliminate stray air currents and prevent evaporation as
much as possible, and placing it in a spare room where it has been
stationary for two weeks.

Today I emptied the water and inspected the bowl. I poured the water
out and carefully (so as not to destroy evidence) wiped the interior
with a paper towel to dry it - the results? None. The dry bowl
evidences no marks, discoloration, nothing to indicate that it ever
had water in it.

Another urban myth destroyed.
Cheers,
Bruce in Bangkok

Ah those stupid jerks, writing up some story in a rag called Science -
whatever THAT means!
I'll write to tell them to straighten out their act, now somebody has
done a REAL experiment.
*
*
This is what they wrote, back in 2004:
*
*
Sudden Onset of Pitting Corrosion on Stainless Steel as a Critical
Phenomenon
C. Punckt,1 M. Bölscher,1 H. H. Rotermund,1 A. S. Mikhailov,1 L. Organ,2
N. Budiansky,3 J. R. Scully,3 J. L. Hudson2*

Stainless steels undergo a sharp rise in pitting corrosion rate as the
potential, solution concentration, or temperature is changed only
slightly. We report experiments using real-time microscopic in situ
visualizations that resolve the nucleation and evolution of individual
pits during the transition. They suggest that the sudden onset of
corrosion is explained by an explosive autocatalytic growth in the
number of metastable pits and that stabilization of individual pits
takes place only later. This finding agrees with a theoretical approach
treating the onset of pitting corrosion as a cooperative critical
phenomenon resulting from interactions among metastable pits, and it
extends perspectives on the control and prevention of corrosion onset.

1 Abteilung Physikalische Chemie, Fritz-Haber-Institut der
Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
2 Department of Chemical Engineering, 102 Engineers' Way, University of
Virginia, Charlottesville, VA 22904–4741, USA.
3 Department of Material Science and Engineering, 102 Engineers' Way,
University of Virginia, Charlottesville, VA 22904–4741, USA.

* To whom correspondence should be addressed. E-mail:

"All commonly used stainless steels and other passive-film–forming
metals, which are designed to be corrosion-resistant, can nevertheless
undergo localized pitting corrosion, which rapidly leads to their
failure. The total annual costs due to corrosion in the United States
are estimated at 3% of the gross national product (1), and a third of
chemical plant failures are attributed to localized corrosion (2).
Localized corrosion is preceded by the appearance of metastable pits:
tiny corrosion seeds the size of a few micrometers developing on the
metal surface, which is naturally protected by an oxide layer. Each pit
produces a small spike of a few seconds duration in the electrical
current, indicating an anodic reaction, and the spike then dies out.
Experimental and theoretical studies have largely clarified the
mechanism for the initiation of these microscopic pits as being caused
by localized electrodissolution of metal at surface defects and
inclusions (3–8).

Pitting corrosion shows a sharp rise in corrosion rate that occurs with
only a small change in conditions, such as applied potential, corrodant
concentrations, or temperature (9). This corresponds to a sudden
transition from a low-activity regime with a few metastable pits to a
state with high pitting activity (10, 11). The transition has been
explained by a stabilization of individual pits (12). As an alternate
explanation, we suggest that the onset of pitting corrosion represents a
cooperative critical phenomenon. In previous investigations, temporal
statistical correlations between the spikes in the total current have
been found (13, 14), indicating some memory in the pitting process (15).
A stochastic spatiotemporal model of the corrosion onset has been
proposed (16). According to this model, electrochemical reactions at a
metastable pit change ion concentrations and weaken the protective film
over defect sites. Each pit enhances the probability of appearance of
further pits at defect sites within a wide zone of weakened film around
it. We show below that autocatalytic reproduction of pits can take
place. Sudden transitions are thus associated with an explosive growth
in the number of active pits. Stabilization of individual pits would
occur only after the transition.
/and so on/

:-)
Regards
Brian W
P.S.
Perhaps adding salt, or even doing as suggested, and filling with water
from the harbor might have a different outcome. Who knows?

Bruce in Bangkok wrote in
:

Another urban myth destroyed.


Now try it with seawater....(c;]



--
-----
Larry

If a man goes way out into the woods all alone and says something,
is it still wrong, even though no woman hears him?

On Fri, 15 May 2009 22:12:37 -0500, Brian Whatcott
wrote:

Bruce in Bangkok wrote:
Some time ago there was a discussion of the stainless properties of
stainless steel:

***
If you have a stainless steel bucket, then you are in a position to
do a little experiment then. One you are convinced will be harmless
even.

Half fill the bucket over the side of your boat, and leave it on deck
- half full, untouched, unstirred. What could be easier?
Let us know how long it takes for the bucket to dry out.....
(one way or another! :-)*
*
*
*
I decided to try out the suggestion and filled a stainless steel
mixing bowl (my wife's actually) with tap water, wrapping it with
saran wrap to eliminate stray air currents and prevent evaporation as
much as possible, and placing it in a spare room where it has been
stationary for two weeks.

Today I emptied the water and inspected the bowl. I poured the water
out and carefully (so as not to destroy evidence) wiped the interior
with a paper towel to dry it - the results? None. The dry bowl
evidences no marks, discoloration, nothing to indicate that it ever
had water in it.

Another urban myth destroyed.
Cheers,
Bruce in Bangkok

Ah those stupid jerks, writing up some story in a rag called Science -
whatever THAT means!
I'll write to tell them to straighten out their act, now somebody has
done a REAL experiment.
*
*

You will, I hope, note that I never argued that stainless would not
corrode in the presence of "stale" water, for want of a better word.

Only that a bucket of water would not corrode "over night", as it
were. which it didn't.

Cheers,

Bruce in Bangkok
(bruceinbangkokatgmaildotcom)

On Sat, 16 May 2009 03:19:08 +0000, Larry wrote:

Bruce in Bangkok wrote in
:

Another urban myth destroyed.


Now try it with seawater....(c;]

I have... at least I have a propeller shaft that has been in salt
water for ten years, or more.

I'll mention again that I wasn't arguing that stainless doesn't
corrode, rather that it is not an "over night" phenomena .


Cheers,

Bruce in Bangkok
(bruceinbangkokatgmaildotcom)

Bruce,
Your tests were not valid because you did not reproduce corrosive cases.
Stainless is corrosion resistant only as long as the passive film of oxide
remains on its surface. This passive film can be removed mechanically and
electrically, but in both cases the material will attempt to absorb oxygen
from its environment to recreate the passive film. If the environment is
oxygen depleted, corrosion occurs very rapidly. Here is a case in point,
stainless bolts holding a cast lead ballast plug where water seeps in slowly
surrounding the bolt, but with very slow or negligible flow. As the hull
moves the leads ballast shifts around ever so slightly , but enough to
abrade the passive film. In short order, the surrounding water is depleted
of free oxygen. That is when corrosion starts. It is commonly called crevice
corrosion. Please also appreciate that stainless steel in homogenous, in
that it is an alloy of multiple metals.The corrosion resistance it displays
depends on this homogenous blend. Any disturbance of this blend also
endangers its corrosion resistance, like welding. This fact necessitates
repassivating the disturbed surface in order to restore the original
corrosion resistance. Repassivation is accomplished by removing the
non-homogenous metals from the surface that migrated there during the molten
state while welding. This is accomplished mechanically, electrically or
chemically with acid.
Steve

"Bruce in Bangkok" wrote in message
...

Some time ago there was a discussion of the stainless properties of
stainless steel:

Stainless steel does well in relatively dry environments with access to
oxygen. Look at your home cutlery, for example.
Then go buy a stainless bowl and fill it half full of water.

See how long it takes to develop its first pin hole.
A matter of weeks or less, quite likely.


No, that is an exaggeration. In fact I have a stainless bucket - said
to have been made in India - that has been on the boat, and in general
use for some ten years. No holes yet.

Cheers,

Bruce in Bangkok

If you have a stainless steel bucket, then you are in a position to
do a little experiment then. One you are convinced will be harmless
even.

Half fill the bucket over the side of your boat, and leave it on deck
-
half full, untouched, unstirred. What could be easier? Let us know how
long it takes for the bucket to dry out..... (one way or another! :-)
This is not such a risky proposition for a hot galvanized bucket of
the traditional design though....


I decided to try out the suggestion and filled a stainless steel
mixing bowl (my wife's actually) with tap water, wrapping it with
saran wrap to eliminate stray air currents and prevent evaporation as
much as possible, and placing it in a spare room where it has been
stationary for two weeks.

Today I emptied the water and inspected the bowl. I poured the water
out and carefully (so as not to destroy evidence) wiped the interior
with a paper towel to dry it - the results? None. The dry bowl
evidences no marks, discoloration, nothing to indicate that it ever
had water in it.

Another urban myth destroyed.



Cheers,

Bruce in Bangkok
(bruceinbangkokatgmaildotcom)

On Sat, 16 May 2009 11:03:08 +0200, "Steve Lusardi"
wrote:

Bruce,
Your tests were not valid because you did not reproduce corrosive cases.
Stainless is corrosion resistant only as long as the passive film of oxide
remains on its surface. This passive film can be removed mechanically and
electrically, but in both cases the material will attempt to absorb oxygen
from its environment to recreate the passive film. If the environment is
oxygen depleted, corrosion occurs very rapidly. Here is a case in point,
stainless bolts holding a cast lead ballast plug where water seeps in slowly
surrounding the bolt, but with very slow or negligible flow. As the hull
moves the leads ballast shifts around ever so slightly , but enough to
abrade the passive film. In short order, the surrounding water is depleted
of free oxygen. That is when corrosion starts. It is commonly called crevice
corrosion. Please also appreciate that stainless steel in homogenous, in
that it is an alloy of multiple metals.The corrosion resistance it displays
depends on this homogenous blend. Any disturbance of this blend also
endangers its corrosion resistance, like welding. This fact necessitates
repassivating the disturbed surface in order to restore the original
corrosion resistance. Repassivation is accomplished by removing the
non-homogenous metals from the surface that migrated there during the molten
state while welding. This is accomplished mechanically, electrically or
chemically with acid.
Steve


You didn't read the original post, that I quoted. The original post
stated:

Stainless steel does well in relatively dry environments with access to
oxygen. Look at your home cutlery, for example.
Then go buy a stainless bowl and fill it half full of water.
See how long it takes to develop its first pin hole.
A matter of weeks or less, quite likely.

Which was all I was debating. Not the fact that stainless will
corrode....

Cheers,

Bruce in Bangkok
(bruceinbangkokatgmaildotcom)

"Bruce in Bangkok" wrote in message
...

Some time ago there was a discussion of the stainless properties of
stainless steel:

Stainless steel does well in relatively dry environments with access to
oxygen. Look at your home cutlery, for example.
Then go buy a stainless bowl and fill it half full of water.

See how long it takes to develop its first pin hole.
A matter of weeks or less, quite likely.


No, that is an exaggeration. In fact I have a stainless bucket - said
to have been made in India - that has been on the boat, and in general
use for some ten years. No holes yet.

Cheers,

Bruce in Bangkok

If you have a stainless steel bucket, then you are in a position to
do a little experiment then. One you are convinced will be harmless
even.

Half fill the bucket over the side of your boat, and leave it on deck
-
half full, untouched, unstirred. What could be easier? Let us know how
long it takes for the bucket to dry out..... (one way or another! :-)
This is not such a risky proposition for a hot galvanized bucket of
the traditional design though....


I decided to try out the suggestion and filled a stainless steel
mixing bowl (my wife's actually) with tap water, wrapping it with
saran wrap to eliminate stray air currents and prevent evaporation as
much as possible, and placing it in a spare room where it has been
stationary for two weeks.

Today I emptied the water and inspected the bowl. I poured the water
out and carefully (so as not to destroy evidence) wiped the interior
with a paper towel to dry it - the results? None. The dry bowl
evidences no marks, discoloration, nothing to indicate that it ever
had water in it.

Another urban myth destroyed.



Cheers,

Bruce in Bangkok
(bruceinbangkokatgmaildotcom)



That's a perfect experiment for you Bruce. Why, you could conduct that
experiment for 30 continuous years while you've sat there at the dock.


Wilbur Hubbard

On Sat, 16 May 2009 16:38:30 +0700, Bruce in Bangkok
wrote:

Then go buy a stainless bowl and fill it half full of water.
See how long it takes to develop its first pin hole.
A matter of weeks or less, quite likely.

Which was all I was debating. Not the fact that stainless will
corrode....

I had a stainless bowl develop a pinhole in ordinary use.

Casady

On Sun, 17 May 2009 12:20:02 -0500, Richard Casady
wrote:

On Sat, 16 May 2009 16:38:30 +0700, Bruce in Bangkok
wrote:

Then go buy a stainless bowl and fill it half full of water.
See how long it takes to develop its first pin hole.
A matter of weeks or less, quite likely.

Which was all I was debating. Not the fact that stainless will
corrode....

I had a stainless bowl develop a pinhole in ordinary use.

Casady


In a matter of weeks?


Cheers,

Bruce in Bangkok
(bruceinbangkokatgmaildotcom)