On Wed, 29 Apr 2009 22:16:38 -0500, Brian Whatcott
wrote:

Can I guess that you are relying on zincs near the prop shaft?
That would be the ONLY reason the pitting was not severe.

Brian W

Of course there are zincs on the shaft - there is a bronze propeller
on the shaft too. But I have a stainless rudder post and a stainless
wind vane steerer shaft that do not have incompatible metals attached
and don't have zincs which don't have corrosion either.

But quit quibbling. I posted something about monel screws, there are
plenty of sources for them and whether you "need" them or not is of
course your decision.



Bruce in Bangkok wrote:
On Wed, 29 Apr 2009 11:57:55 -0500, Brian Whatcott
wrote:

Show me the stainless alloy that does not corrode when submerged for
long in salt water, and I'm your man.

BrianW

Actually quite a few. Even 304 does not corrode rapidly and I have a
316 propeller shaft that I installed 10 years ago and still exhibits
no corrosion.

What, exactly are you planning on using these fasteners for? Certainly
sufficient 3xx stainless is being used in the marine industry today
that you should have confidence that this alloy will resist corrosion
for a reasonable length of time.


Steve Lusardi wrote:
Brian,
Please do the research if you disagree. Stainless fasteners exhibit far
greater strength and fatigue resistance, which by the way is poor for the
whole nickel alloy family and depending on the alloy, exhibit every bit as
good resistance to corrosion. May I also point out that nickel alloys
fasteners are not always the best solution for corrosive and electrolytic
environments and that includes monel. So, assuming your application
qualifies for a nickel alloy solution, why in the world would you choose
monel, when SS is better and less expensive?
Steve

"Brian Whatcott" wrote in message
...
Strong AND corrosion-resistant!
I'm all ears! Bronze? Particular brasses? Not stainless nor alloy steel
nor mild steel certainly. Some aluminum alloys? possibly.
nickel alloys (other than monel??) Titanium??

Brian W

Steve Lusardi wrote:
Ezcellent? I don't think so. There are other materials far better for
both strength and corrosion resistance. There are reasons why they are
hard to find.
Steve
Cheers,

Bruce in Bangkok
(bruceinbangkokatgmaildotcom)

316, 316l, 316Ti, but like Monel, these alloys are all subject to crevice
corrosion. Their corrosion resistance is due to their ability to absorb
oxygen on their surface and if under even mild abrasion or electrolysis and
the environment becomes oxygen depleted, they corrode very quickly. So, the
answer is to make certain that water flows around the fastener, anti sieze
is used on the threads and it isn't mounted near dissimilar metals and your
golden.
Steve

"Brian Whatcott" wrote in message
...
Show me the stainless alloy that does not corrode when submerged for long
in salt water, and I'm your man.

BrianW

Steve Lusardi wrote:
Brian,
Please do the research if you disagree. Stainless fasteners exhibit far
greater strength and fatigue resistance, which by the way is poor for the
whole nickel alloy family and depending on the alloy, exhibit every bit
as good resistance to corrosion. May I also point out that nickel alloys
fasteners are not always the best solution for corrosive and electrolytic
environments and that includes monel. So, assuming your application
qualifies for a nickel alloy solution, why in the world would you choose
monel, when SS is better and less expensive?
Steve

"Brian Whatcott" wrote in message
...
Strong AND corrosion-resistant!
I'm all ears! Bronze? Particular brasses? Not stainless nor alloy
steel nor mild steel certainly. Some aluminum alloys? possibly.
nickel alloys (other than monel??) Titanium??

Brian W

Steve Lusardi wrote:
Ezcellent? I don't think so. There are other materials far better for
both strength and corrosion resistance. There are reasons why they are
hard to find.
Steve

One additional point, Monel is a stainless steel alloy. It's primary use is
for high temperature strength and resistance to corrosion, 1000 degrees C
and higher. It will retain 90% of its room temperature strength when red
hot.
Steve

"Steve Lusardi" wrote in message
...
316, 316l, 316Ti, but like Monel, these alloys are all subject to crevice
corrosion. Their corrosion resistance is due to their ability to absorb
oxygen on their surface and if under even mild abrasion or electrolysis
and the environment becomes oxygen depleted, they corrode very quickly.
So, the answer is to make certain that water flows around the fastener,
anti sieze is used on the threads and it isn't mounted near dissimilar
metals and your golden.
Steve

"Brian Whatcott" wrote in message
...
Show me the stainless alloy that does not corrode when submerged for long
in salt water, and I'm your man.

BrianW

Steve Lusardi wrote:
Brian,
Please do the research if you disagree. Stainless fasteners exhibit far
greater strength and fatigue resistance, which by the way is poor for
the whole nickel alloy family and depending on the alloy, exhibit every
bit as good resistance to corrosion. May I also point out that nickel
alloys fasteners are not always the best solution for corrosive and
electrolytic environments and that includes monel. So, assuming your
application qualifies for a nickel alloy solution, why in the world
would you choose monel, when SS is better and less expensive?
Steve

"Brian Whatcott" wrote in message
...
Strong AND corrosion-resistant!
I'm all ears! Bronze? Particular brasses? Not stainless nor alloy
steel nor mild steel certainly. Some aluminum alloys? possibly.
nickel alloys (other than monel??) Titanium??

Brian W

Steve Lusardi wrote:
Ezcellent? I don't think so. There are other materials far better for
both strength and corrosion resistance. There are reasons why they are
hard to find.
Steve

Steve Lusardi wrote:
One additional point, Monel is a stainless steel alloy.

Really? http://www.espi-metals.com/metals/monel.pdf
Alloy 400 has 2.5% iron and Alloy K-500 has 2%. A high copper steel
typically has less than 2% copper. Monel is around 30% and it's *NOT* a
steel!

It's primary use is
for high temperature strength and resistance to corrosion, 1000 degrees C
and higher.

540 deg C is in the middle of the heat treatment temperature range for
Monel K-500. 1000 deg C is around the temperature required to solution
anneal this alloy. Its properties are stable below 425 deg C.
http://www.hightempmetals.com/techdata/hitempMonelK500data.php

It will retain 90% of its room temperature strength when red
hot.
Steve

"Steve Lusardi" wrote in message
...
316, 316l, 316Ti, but like Monel, these alloys are all subject to crevice
corrosion. Their corrosion resistance is due to their ability to absorb
oxygen on their surface and if under even mild abrasion or electrolysis
and the environment becomes oxygen depleted, they corrode very quickly.
So, the answer is to make certain that water flows around the fastener,
anti sieze is used on the threads and it isn't mounted near dissimilar
metals and your golden.
Steve

"Brian Whatcott" wrote in message
...
Show me the stainless alloy that does not corrode when submerged for long
in salt water, and I'm your man.

BrianW

Steve Lusardi wrote:
Brian,
Please do the research if you disagree. Stainless fasteners exhibit far
greater strength and fatigue resistance, which by the way is poor for
the whole nickel alloy family and depending on the alloy, exhibit every
bit as good resistance to corrosion. May I also point out that nickel
alloys fasteners are not always the best solution for corrosive and
electrolytic environments and that includes monel. So, assuming your
application qualifies for a nickel alloy solution, why in the world
would you choose monel, when SS is better and less expensive?
Steve

"Brian Whatcott" wrote in message
...
Strong AND corrosion-resistant!
I'm all ears! Bronze? Particular brasses? Not stainless nor alloy
steel nor mild steel certainly. Some aluminum alloys? possibly.
nickel alloys (other than monel??) Titanium??

Brian W

Steve Lusardi wrote:
Ezcellent? I don't think so. There are other materials far better for
both strength and corrosion resistance. There are reasons why they are
hard to find.
Steve





--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL:

Bruce in Bangkok wrote:
...I have a stainless rudder post and a stainless
wind vane steerer shaft that do not have incompatible metals attached
and don't have zincs which don't have corrosion either.

But quit quibbling. I posted something about monel screws, there are
plenty of sources for them and whether you "need" them or not is of
course your decision.

Huh?
I was responding to somebody that
1) wants monel screws
2) apparently understands their anti-corrosion qualities.

Brian W

Hi Steve,

when you describe monel as a stainless steel,
you defeat your position.

Brian W

Steve Lusardi wrote:
One additional point, Monel is a stainless steel alloy. It's primary use is
for high temperature strength and resistance to corrosion, 1000 degrees C
and higher. It will retain 90% of its room temperature strength when red
hot.
Steve

"Steve Lusardi" wrote in message
...
316, 316l, 316Ti, but like Monel, these alloys are all subject to crevice
corrosion.

On Thu, 30 Apr 2009 07:12:36 -0500, Brian Whatcott
wrote:

Bruce in Bangkok wrote:
...I have a stainless rudder post and a stainless
wind vane steerer shaft that do not have incompatible metals attached
and don't have zincs which don't have corrosion either.

But quit quibbling. I posted something about monel screws, there are
plenty of sources for them and whether you "need" them or not is of
course your decision.

Huh?
I was responding to somebody that
1) wants monel screws
2) apparently understands their anti-corrosion qualities.

Brian W

Well, obviously things get a bit confused after a while. I must admit
that I didn't follow the thread when it started. Just chimed in when
the comment about no stainless that don't corrode under water came up.

Cheers,

Bruce in Bangkok
(bruceinbangkokatgmaildotcom)

"Bruce in Bangkok" wrote:

Well, obviously things get a bit confused after a while. I must
admit
that I didn't follow the thread when it started. Just chimed in when
the comment about no stainless that don't corrode under water came
up.

As long as you brought it up again, "stainless" actually should be
written as "Stain Less".

Sooner or later, it all pits.

About all 304 (AKA: 18-8) is good for is cooking pots and pans, also
classified as intermittent service..

It certainly has no place in a marine environment, IMHO.

316L is a step up the food chain, but even that has it's limitations.

Lew

On Fri, 01 May 2009 03:01:12 GMT, "Lew Hodgett"
wrote:


"Bruce in Bangkok" wrote:

Well, obviously things get a bit confused after a while. I must
admit
that I didn't follow the thread when it started. Just chimed in when
the comment about no stainless that don't corrode under water came
up.

As long as you brought it up again, "stainless" actually should be
written as "Stain Less".

Sooner or later, it all pits.

About all 304 (AKA: 18-8) is good for is cooking pots and pans, also
classified as intermittent service..

It certainly has no place in a marine environment, IMHO.

316L is a step up the food chain, but even that has it's limitations.

Lew


From the Wiki (the font of all knowledge :-)

In metallurgy, stainless steel, also known as inox steel or inox, is
defined as a steel alloy with a minimum of 11% chromium content by
mass.[1] Stainless steel does not stain, corrode, or rust as easily as
ordinary steel (it stains less), but it is not stain-proof.
--------------

I wouldn't argue that 304 is the alloy of choice for marine use but I
have rails on a 40' boat that were built from 304 and 10 after years
of use there is no corrosion on them.

I have this feeling that people read recommendations as carved in
tablets of stone rather then as conservative suggestions. As I said in
another post the rudder post (built in 1973) is stainless with no
signs of corrosion yet...


Cheers,

Bruce in Bangkok
(bruceinbangkokatgmaildotcom)

Bruce in Bangkok wrote:


I wouldn't argue that 304 is the alloy of choice for marine use but I
have rails on a 40' boat that were built from 304 and 10 after years
of use there is no corrosion on them....

Bruce in Bangkok
(bruceinbangkokatgmaildotcom)

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.

Brian W