I am building the aluminum tanks for the radiator (still) and am
wondering about putting in a rust trap, inside the smaller tank. I have
a 3/4"-16NF cap and tank fitting already made, so whatever I do has to
fit through a 3/4" hole. The magnets are pulled out occasionally (once
or twice a year) to spray the accumulated rust off.

NiB is the strongest magnets, but I have found accounts online stating
that samarium cobalt rusts less than neodymium magnets will. The
commercial filters seem to use plastic-encapsulated magnets of unknown
composition.


,,,,,,,
I heard about this matter (of rust magnets in coolant systems) once
online somewhere--might have been here. Somebody said that if you put a
magnet into the coolant reservoir tank, it will catch the rust as the
coolant cycles in & out..... but now after researching it a bit,,,, I am
wondering if the magnet itself is rusting, then how would you tell how
much it was pulling out of the coolant?

So ideally the magnet shouldn't rust at all...
,,,,,,


How fast will these things rust in typical car coolant? Should I just
build the mount to allow replacing the magnets? I plan on using some
smaller 3/16"~1/4" diameter ones in a stack, with spacers in-between them.

Alternately I could just coat them with some silicone or buna-n sealant
I guess. Anybody have any experience with these things?

DougC wrote:
I am building the aluminum tanks for the radiator (still) and am
wondering about putting in a rust trap, inside the smaller tank. I
have a 3/4"-16NF cap and tank fitting already made, so whatever I do
has to fit through a 3/4" hole. The magnets are pulled out
occasionally (once or twice a year) to spray the accumulated rust off.

NiB is the strongest magnets, but I have found accounts online stating
that samarium cobalt rusts less than neodymium magnets will. The
commercial filters seem to use plastic-encapsulated magnets of unknown
composition.


,,,,,,,
I heard about this matter (of rust magnets in coolant systems) once
online somewhere--might have been here. Somebody said that if you put
a magnet into the coolant reservoir tank, it will catch the rust as
the coolant cycles in & out..... but now after researching it a
bit,,,, I am wondering if the magnet itself is rusting, then how would
you tell how much it was pulling out of the coolant?

So ideally the magnet shouldn't rust at all...
,,,,,,


How fast will these things rust in typical car coolant? Should I just
build the mount to allow replacing the magnets? I plan on using some
smaller 3/16"~1/4" diameter ones in a stack, with spacers in-between
them.

Alternately I could just coat them with some silicone or buna-n
sealant I guess. Anybody have any experience with these things?
Maybe here for some ideas
http://www.vp-scientific.com/peek_en..._stir_bars.htm ,
Useful as some magnet formulations lose their properties at relatively
low temperatures.

I've seen other water proofed rare earths elsewhere but can't find them
at the moment.

On Fri, 03 Feb 2012 15:52:46 -0600, DougC
wrote:

I am building the aluminum tanks for the radiator (still) and am
wondering about putting in a rust trap, inside the smaller tank. I have
a 3/4"-16NF cap and tank fitting already made, so whatever I do has to
fit through a 3/4" hole. The magnets are pulled out occasionally (once
or twice a year) to spray the accumulated rust off.

NiB is the strongest magnets, but I have found accounts online stating
that samarium cobalt rusts less than neodymium magnets will. The
commercial filters seem to use plastic-encapsulated magnets of unknown
composition.


,,,,,,,
I heard about this matter (of rust magnets in coolant systems) once
online somewhere--might have been here. Somebody said that if you put a
magnet into the coolant reservoir tank, it will catch the rust as the
coolant cycles in & out..... but now after researching it a bit,,,, I am
wondering if the magnet itself is rusting, then how would you tell how
much it was pulling out of the coolant?

So ideally the magnet shouldn't rust at all...
,,,,,,


How fast will these things rust in typical car coolant? Should I just
build the mount to allow replacing the magnets? I plan on using some
smaller 3/16"~1/4" diameter ones in a stack, with spacers in-between them.

Alternately I could just coat them with some silicone or buna-n sealant
I guess. Anybody have any experience with these things?

I used custom samarium cobalt magnets once. Had to design and build
magnetic stirrers to handle 215 C. Neodymium won't cut it at that
temp. Mine weren't submerged, and the ones that were were teflon
coated. Good thing considering what they were stirring.

Pete Keillor

"Pete Keillor" wrote in message
...
On Fri, 03 Feb 2012 15:52:46 -0600, DougC
wrote:

I am building the aluminum tanks for the radiator (still) and am
wondering about putting in a rust trap, inside the smaller tank. I have
a 3/4"-16NF cap and tank fitting already made, so whatever I do has to
fit through a 3/4" hole. The magnets are pulled out occasionally (once
or twice a year) to spray the accumulated rust off.

On my tractor I pressed a stainless-clad magnet into the drilled end of the
drain bolt.

jsw

On 2/3/2012 6:20 PM, Jim Wilkins wrote:
"Pete wrote in message
...
On Fri, 03 Feb 2012 15:52:46 -0600,
wrote:

I am building the aluminum tanks for the radiator (still) and am
wondering about putting in a rust trap, inside the smaller tank. I have
a 3/4"-16NF cap and tank fitting already made, so whatever I do has to
fit through a 3/4" hole. The magnets are pulled out occasionally (once
or twice a year) to spray the accumulated rust off.

On my tractor I pressed a stainless-clad magnet into the drilled end of the
drain bolt.

jsw



How hot does a car's coolant get?
Radiator hoses are usually buna-n rubber that has a typical max temp of
212F continuous.

Researchin......
Neodymium seems to lose strength beginning at 176F
Samarium cobalt begins at around 500F
Alinco goes to 900F

I guess I will just use samarium cobalt and mount them upside-down, so
they don't get wet. Its what I'm doing with the drain plug threads, to
keep them from fouling.

"DougC" wrote in message
...
On 2/3/2012 6:20 PM, Jim Wilkins wrote:
...
On my tractor I pressed a stainless-clad magnet into the drilled end of
the
drain bolt.

jsw

How hot does a car's coolant get?
Radiator hoses are usually buna-n rubber that has a typical max temp of
212F continuous.

The antifreeze mix boils hotter than plain water and the pressure cap also
raises the boiling point. Here's a table:
http://avenger-valkyrie.org/techinfo/antifreeze.htm

A 50% mix with a 15 PSI cap can reach 265F. The usual careless mixing
doesn't change it too much.

jsw