Mag Drive 5 with metal screws

Alex and Wayne,

Thanks! I had a few minutes from work to give Danner a call - they told
me that the screw are medical grade stainless steel, so as Wayne said,
they're safe. I'm going to avoid my usual overdoing and try not to
order the plastic ones...

Marty

MartyPowerJazz wrote:
I'm going to avoid my usual overdoing and try not to
order the plastic ones...

Hello again,

Before you decide that replacing the screws is "overdoing" read this:
http://tinyurl.com/y9jqz7

The article describes why stainless steel is stainless and also why
stainless steel often isn't stainless in certain environments.
Specifically, two situations that can overcome the chemistry of SS are
as follows:

1. An oxygen poor environment - This is what you get on SS surfaces
that are in tight contact with another surface such as in the case of
SS screws. It's sometimes referred to as "crevice corrosion" and is a
well known problem in the marine trades (ships, boats, offshore oil
rigs, etc.)

2. Galvanic corrosion - This one comes from the chloride ions in
sal****er attacking the protective film that SS produces on its
surface; basically, seawater is capable of breaking down this film
faster than the SS can regenerate it.

Read through the thread I linked in my earlier post and you'll see that
some of the participants had rusting of the SS screws in their Mag 5's.
One guy claimed that it caused some mortality in his tank but I'm a bit
suspicious of that claim. OTOH: At the very least, corroded screws
would make pump maintenance more difficult.

Caveat: I have never owned a Mag 5 but I have seen many instances of
crevice corrosion in sal****er environments.


Stainlessly yours,

Alex

Rust won't hurt anything. Rust is iron oxide. There are
other metals in stainless steel, but I would not think
that they would stay in solution any longer than iron.

As far as stainless steal holding up in salt water, that
depends on the grade of stainless steal.

Low oxygen does not cause rust. In fact keep iron in an
oxygen free environment, and it will never rust.

But yes the chlorine in the salt can dissolve it by
creating metal chlorides. I would not worry about it
unless it was creating a structural problem.

Where screws corrode fast is where they are in contact
with a different metal in salt water.

Wayne Sallee
Wayne's Pets



Tidepool Geek wrote on 11/3/2006 2:26 PM:
MartyPowerJazz wrote:
I'm going to avoid my usual overdoing and try not to
order the plastic ones...

Hello again,

Before you decide that replacing the screws is "overdoing" read this:
http://tinyurl.com/y9jqz7

The article describes why stainless steel is stainless and also why
stainless steel often isn't stainless in certain environments.
Specifically, two situations that can overcome the chemistry of SS are
as follows:

1. An oxygen poor environment - This is what you get on SS surfaces
that are in tight contact with another surface such as in the case of
SS screws. It's sometimes referred to as "crevice corrosion" and is a
well known problem in the marine trades (ships, boats, offshore oil
rigs, etc.)

2. Galvanic corrosion - This one comes from the chloride ions in
sal****er attacking the protective film that SS produces on its
surface; basically, seawater is capable of breaking down this film
faster than the SS can regenerate it.

Read through the thread I linked in my earlier post and you'll see that
some of the participants had rusting of the SS screws in their Mag 5's.
One guy claimed that it caused some mortality in his tank but I'm a bit
suspicious of that claim. OTOH: At the very least, corroded screws
would make pump maintenance more difficult.

Caveat: I have never owned a Mag 5 but I have seen many instances of
crevice corrosion in sal****er environments.


Stainlessly yours,

Alex

Mag drive uses two types of screws, stainless steal, and a
dark colored screw. The dark colored screw holds up better
than the ss screw. It seems odd the way they sometimes use
one over the other.

Wayne Sallee
Wayne's Pets

They used to use the ss in pond mag pumps, and the dark
ones in the aquarium mag pumps, but now you never know
which ones they will use.

Wayne Sallee
Wayne's Pets



Wayne Sallee wrote on 11/3/2006 4:20 PM:
Mag drive uses two types of screws, stainless steal, and a dark colored
screw. The dark colored screw holds up better than the ss screw. It
seems odd the way they sometimes use one over the other.

Wayne Sallee
Wayne's Pets

Just a simple observation...My mag 9.5 has been running for 2 years
no rust. I'll leave the engineering materials conversation alone.
I do enough of this during the day.

Chris


"Wayne Sallee" wrote in message
nk.net...
They used to use the ss in pond mag pumps, and the dark ones in the
aquarium mag pumps, but now you never know which ones they will use.

Wayne Sallee
Wayne's Pets



Wayne Sallee wrote on 11/3/2006 4:20 PM:
Mag drive uses two types of screws, stainless steal, and a dark colored
screw. The dark colored screw holds up better than the ss screw. It seems
odd the way they sometimes use one over the other.

Wayne Sallee
Wayne's Pets

nylon screw are 2 cents a piece. my mag3screws rusted after a number of
months. the screws on their own are ok, but when you take a screwdriver
which is a different typ of metal, it introduces little metal on metal
scrapes which can rust. for 8 cents you might as well have piece of mind


"TheRock" wrote in message news:U1P2h.74$qJ6.45@trndny07...
Just a simple observation...My mag 9.5 has been running for 2 years
no rust. I'll leave the engineering materials conversation alone.
I do enough of this during the day.

Chris


"Wayne Sallee" wrote in message
nk.net...
They used to use the ss in pond mag pumps, and the dark ones in the
aquarium mag pumps, but now you never know which ones they will use.

Wayne Sallee
Wayne's Pets



Wayne Sallee wrote on 11/3/2006 4:20 PM:
Mag drive uses two types of screws, stainless steal, and a dark colored
screw. The dark colored screw holds up better than the ss screw. It
seems odd the way they sometimes use one over the other.

Wayne Sallee
Wayne's Pets

rust WILL hurt stuff. SPS will start to die with rust in the system, The
screws on the mag pumps will eventually rust in salt water. Save yourself
the headache and the money and replace them with nylon screws from us
plastics

"Wayne Sallee" wrote in message
k.net...
Rust won't hurt anything. Rust is iron oxide. There are other metals in
stainless steel, but I would not think that they would stay in solution
any longer than iron.

As far as stainless steal holding up in salt water, that depends on the
grade of stainless steal.

Low oxygen does not cause rust. In fact keep iron in an oxygen free
environment, and it will never rust.

But yes the chlorine in the salt can dissolve it by creating metal
chlorides. I would not worry about it unless it was creating a structural
problem.

Where screws corrode fast is where they are in contact with a different
metal in salt water.

Wayne Sallee
Wayne's Pets



Tidepool Geek wrote on 11/3/2006 2:26 PM:
MartyPowerJazz wrote:
I'm going to avoid my usual overdoing and try not to
order the plastic ones...

Hello again,

Before you decide that replacing the screws is "overdoing" read this:
http://tinyurl.com/y9jqz7

The article describes why stainless steel is stainless and also why
stainless steel often isn't stainless in certain environments.
Specifically, two situations that can overcome the chemistry of SS are
as follows:

1. An oxygen poor environment - This is what you get on SS surfaces
that are in tight contact with another surface such as in the case of
SS screws. It's sometimes referred to as "crevice corrosion" and is a
well known problem in the marine trades (ships, boats, offshore oil
rigs, etc.)

2. Galvanic corrosion - This one comes from the chloride ions in
sal****er attacking the protective film that SS produces on its
surface; basically, seawater is capable of breaking down this film
faster than the SS can regenerate it.

Read through the thread I linked in my earlier post and you'll see that
some of the participants had rusting of the SS screws in their Mag 5's.
One guy claimed that it caused some mortality in his tank but I'm a bit
suspicious of that claim. OTOH: At the very least, corroded screws
would make pump maintenance more difficult.

Caveat: I have never owned a Mag 5 but I have seen many instances of
crevice corrosion in sal****er environments.


Stainlessly yours,

Alex

Craig Fisher wrote:
rust WILL hurt stuff.

Sure, but nobody has established that the screws in question contain any iron;
in fact, the OP stated that the company told him they're medical grade stainless
steel, which does not rust.

George Patterson
Those who do not study History are doomed to repeat it. Those who DO
study History are doomed to watch every one else repeat it.

No. Rust will not hurt anything in the a salt water
aquarium. In salt water iron precipitates out too quickly
for it to harm anything, unless you were to just dump a
bunch of soluble iron such as ferric chloride in large doses.

Wayne Sallee
Wayne's Pets



Craig Fisher wrote on 11/12/2006 10:12 AM:
rust WILL hurt stuff. SPS will start to die with rust in the system, The
screws on the mag pumps will eventually rust in salt water. Save yourself
the headache and the money and replace them with nylon screws from us
plastics

"Wayne Sallee" wrote in message
k.net...
Rust won't hurt anything. Rust is iron oxide. There are other metals in
stainless steel, but I would not think that they would stay in solution
any longer than iron.

As far as stainless steal holding up in salt water, that depends on the
grade of stainless steal.

Low oxygen does not cause rust. In fact keep iron in an oxygen free
environment, and it will never rust.

But yes the chlorine in the salt can dissolve it by creating metal
chlorides. I would not worry about it unless it was creating a structural
problem.

Where screws corrode fast is where they are in contact with a different
metal in salt water.

Wayne Sallee
Wayne's Pets



Tidepool Geek wrote on 11/3/2006 2:26 PM:
MartyPowerJazz wrote:
I'm going to avoid my usual overdoing and try not to
order the plastic ones...
Hello again,

Before you decide that replacing the screws is "overdoing" read this:
http://tinyurl.com/y9jqz7

The article describes why stainless steel is stainless and also why
stainless steel often isn't stainless in certain environments.
Specifically, two situations that can overcome the chemistry of SS are
as follows:

1. An oxygen poor environment - This is what you get on SS surfaces
that are in tight contact with another surface such as in the case of
SS screws. It's sometimes referred to as "crevice corrosion" and is a
well known problem in the marine trades (ships, boats, offshore oil
rigs, etc.)

2. Galvanic corrosion - This one comes from the chloride ions in
sal****er attacking the protective film that SS produces on its
surface; basically, seawater is capable of breaking down this film
faster than the SS can regenerate it.

Read through the thread I linked in my earlier post and you'll see that
some of the participants had rusting of the SS screws in their Mag 5's.
One guy claimed that it caused some mortality in his tank but I'm a bit
suspicious of that claim. OTOH: At the very least, corroded screws
would make pump maintenance more difficult.

Caveat: I have never owned a Mag 5 but I have seen many instances of
crevice corrosion in sal****er environments.


Stainlessly yours,

Alex