I have been using Wickes version of aquapanel screws (all 40mm),
ceramic coated. I like them, and having been told that stainless steel
*can* still rust, I would like to use ceramic coated screws where they
will be embedded in concrete. But I need some 50mm long. Where can I
get them ?
TIA,
Simon.

sm_jamieson wrote:
I have been using Wickes version of aquapanel screws (all 40mm),
ceramic coated. I like them, and having been told that stainless steel
*can* still rust, I would like to use ceramic coated screws where they
will be embedded in concrete. But I need some 50mm long. Where can I
get them ?
TIA,
Simon.
Just been looking on US sites for decking screws. They rate them as
zinc coated = good, ceramic coated = better, stainless steel = best.
Maybe I should use stainless steel after all.
What d'y'all think now ?
Simon.

"sm_jamieson" wrote in message
oups.com...

sm_jamieson wrote:
I have been using Wickes version of aquapanel screws (all 40mm),
ceramic coated. I like them, and having been told that stainless steel
*can* still rust, I would like to use ceramic coated screws where they
will be embedded in concrete. But I need some 50mm long. Where can I
get them ?
TIA,
Simon.
Just been looking on US sites for decking screws. They rate them as
zinc coated = good, ceramic coated = better, stainless steel = best.
Maybe I should use stainless steel after all.
What d'y'all think now ?
Simon.


Because you can get stainless virtually everywhere and in any size I've been
using them almost exclusively for everything but concealed work where theres
no chance of damp or water. Never had any problems for what must be at least
3-4 years now on showers, wet rooms, kitchens or external work.

TonyK wrote:
"sm_jamieson" wrote in message
oups.com...

sm_jamieson wrote:
I have been using Wickes version of aquapanel screws (all 40mm),
ceramic coated. I like them, and having been told that stainless steel
*can* still rust, I would like to use ceramic coated screws where they
will be embedded in concrete. But I need some 50mm long. Where can I
get them ?
TIA,
Simon.
Just been looking on US sites for decking screws. They rate them as
zinc coated = good, ceramic coated = better, stainless steel = best.
Maybe I should use stainless steel after all.
What d'y'all think now ?
Simon.


Because you can get stainless virtually everywhere and in any size I've been
using them almost exclusively for everything but concealed work where theres
no chance of damp or water. Never had any problems for what must be at least
3-4 years now on showers, wet rooms, kitchens or external work.

I guess the stainless steel corrosion is under some very particular or
harsh environment. My screws will be embedded in concrete as part of a
composite panel I am making. I'm sure SS will be OK.
Cheers,
Simon.

I guess the stainless steel corrosion is under some very particular or
harsh environment. My screws will be embedded in concrete as part of a
composite panel I am making. I'm sure SS will be OK.

Stainless steel will rust if is immersed in stagnant water - that is
water with very little dissolved oxygen. AIU this is because the rust
resistance of stainless is provided by a surface coating of some kind
of oxide which needs to be renewed continually.

On 26 Sep 2006 08:43:14 -0700, "dcbwhaley" wrote:


I guess the stainless steel corrosion is under some very particular or
harsh environment. My screws will be embedded in concrete as part of a
composite panel I am making. I'm sure SS will be OK.

Stainless steel will rust if is immersed in stagnant water - that is
water with very little dissolved oxygen. AIU this is because the rust
resistance of stainless is provided by a surface coating of some kind
of oxide which needs to be renewed continually.


A well known problem with keel bolts on yachts, small amounts of
moisture (stagnant seawater/bilgewater) and no oxygen can mean hidden
but sometimes huge cross sectional area losses. Sometimes this is
picked up on survey but sometimes the boat just looses its keel, and
is never seen again. Stainless *needs* oxygen to stay rust free.


--

On Wed, 27 Sep 2006 00:00:00 +0100, Matt wrote:

On 26 Sep 2006 08:43:14 -0700, "dcbwhaley" wrote:


I guess the stainless steel corrosion is under some very particular or
harsh environment. My screws will be embedded in concrete as part of a
composite panel I am making. I'm sure SS will be OK.

Stainless steel will rust if is immersed in stagnant water - that is
water with very little dissolved oxygen. AIU this is because the rust
resistance of stainless is provided by a surface coating of some kind
of oxide which needs to be renewed continually.


A well known problem with keel bolts on yachts, small amounts of
moisture (stagnant seawater/bilgewater) and no oxygen can mean hidden
but sometimes huge cross sectional area losses. Sometimes this is
picked up on survey but sometimes the boat just looses its keel, and
is never seen again. Stainless *needs* oxygen to stay rust free.

ISTR also that there are several "grades" of stainless, to suit different
purposes.

The message .com
from "dcbwhaley" contains these words:

AIU this is because the rust
resistance of stainless is provided by a surface coating of some kind
of oxide which needs to be renewed continually.

Chromium. The trick is that chromium oxide isn't more bulky than
chromium 'cos of the way the oxide forms. This means that it doesn't
flake off and reveal more fresh metal underneath. Iron oxide is much
bulkier than iron so it puffs up and reveals more metal to rust some
more.

--
Skipweasel
Pay no attention to that man behind the curtain.

On Wed, 27 Sep 2006 06:05:17 +0100, nog wrote:

On Wed, 27 Sep 2006 00:00:00 +0100, Matt wrote:

On 26 Sep 2006 08:43:14 -0700, "dcbwhaley" wrote:


I guess the stainless steel corrosion is under some very particular or
harsh environment. My screws will be embedded in concrete as part of a
composite panel I am making. I'm sure SS will be OK.

Stainless steel will rust if is immersed in stagnant water - that is
water with very little dissolved oxygen. AIU this is because the rust
resistance of stainless is provided by a surface coating of some kind
of oxide which needs to be renewed continually.


A well known problem with keel bolts on yachts, small amounts of
moisture (stagnant seawater/bilgewater) and no oxygen can mean hidden
but sometimes huge cross sectional area losses. Sometimes this is
picked up on survey but sometimes the boat just looses its keel, and
is never seen again. Stainless *needs* oxygen to stay rust free.

ISTR also that there are several "grades" of stainless, to suit different
purposes.

There are literally hundreds of grades, basically falling into three
basic groups. But no matter what grade is used It won't stop them
severely corroding in the conditions described.


--

"nog" wrote in message
...
On Wed, 27 Sep 2006 00:00:00 +0100, Matt wrote:
....
A well known problem with keel bolts on yachts, small amounts of
moisture (stagnant seawater/bilgewater) and no oxygen can mean hidden
but sometimes huge cross sectional area losses. Sometimes this is
picked up on survey but sometimes the boat just looses its keel, and
is never seen again. Stainless *needs* oxygen to stay rust free.

ISTR also that there are several "grades" of stainless, to suit different
purposes.

Yes, but even double vacuum annealed implant quality stainless will still
corrode under the conditions described.

Colin Bignell

On Wed, 27 Sep 2006 12:50:00 +0100, Matt wrote:

On Wed, 27 Sep 2006 06:05:17 +0100, nog wrote:

On Wed, 27 Sep 2006 00:00:00 +0100, Matt wrote:

On 26 Sep 2006 08:43:14 -0700, "dcbwhaley" wrote:


I guess the stainless steel corrosion is under some very particular or
harsh environment. My screws will be embedded in concrete as part of a
composite panel I am making. I'm sure SS will be OK.

Stainless steel will rust if is immersed in stagnant water - that is
water with very little dissolved oxygen. AIU this is because the rust
resistance of stainless is provided by a surface coating of some kind
of oxide which needs to be renewed continually.


A well known problem with keel bolts on yachts, small amounts of
moisture (stagnant seawater/bilgewater) and no oxygen can mean hidden
but sometimes huge cross sectional area losses. Sometimes this is
picked up on survey but sometimes the boat just looses its keel, and
is never seen again. Stainless *needs* oxygen to stay rust free.

ISTR also that there are several "grades" of stainless, to suit different
purposes.

There are literally hundreds of grades, basically falling into three
basic groups. But no matter what grade is used It won't stop them
severely corroding in the conditions described.

Indeed, but my point was really that the term "stainless" on its own is
insufficient. A great many people think it describes the properties of a
single material.