How can I blacken stainless steel spokes?

On May 15, 10:12*am, wrote:

Dear Ben,

Will itty-bitty headphone magnets stick to your no-attraction spokes?

I don't know. I don't feel like taking apart any
headphones to find out. It wouldn't be the exact
same magnet as yours, so it wouldn't be a direct
comparison anyway. Stainless steels are
not generally absolute zero ferro-magnetism. They're
just weak to very weak compared to ordinary steels.
So if you can find a magnet with a high enough magnetism
to weight ratio, you may be able to get to get it to hang
on a spoke, but that doesn't change that stainless
spokes are noticeably less ferromagnetic than other
steel, including galvanized or chromed spokes.

The more interesting question would be if you and
others can find a correlation between, say, spoke
manufacturer or type and magnetizability, similar
to how I found that Asahi/Wheelsmith are less magnetic
than DT. Although to be honest, it isn't _that_ interesting.

Along with the others, I am sure you meant stainless
when you wrote "aluminum spokes" below. There are
(silly) aluminum-spoked wheels, but you don't own any.

Ben


I vaguely remembered some faintly magnetic spokes, so I tested four of
my wheels.

It turned out that the last wheel fooled me and my hard drive magnet.

***

Wheel #1, galvanized spokes, hard drive magnet hangs handily from a
single spoke, satisfying clunk! as it grabs the spoke:

Wheels #2 & #3, aluminum spokes, hard drive magnet hangs, but only
barely and when pressed against two spokes near the crossing--the weak
attraction means that more metal surface is needed to support the hard
drive magnet.

Wheel #4, aluminum spokes, no attraction . . .

Oops!

Very careful testing of wheel #4 showed that the hard drive magnet
pulled sideways when dangled next to a spoke, but so weakly that there
was no hope of sticking to the spoke--it fell off if I let go.

But an itty-bitty ~6mm round headphone magnet is so small and light
that it sticks on all the spokes, as the photos below show.

Wheel #1 galvanized, hard drive magnet sticks strongly to one spoke:
*http://i44.tinypic.com/2v8s2mg.jpg

Wheel #2 aluminum (same with wheel #3), hard drive magnet can barely
stick to the increased surface of two spokes at the crossing:
*http://i43.tinypic.com/2sk6t.jpg

Wheel #4 aluminum, hard drive magnet won't stick by itself, even at a
spoke crossing, but it can just cling to a spoke if partly supported
by fishing line:
*http://i43.tinypic.com/2mr76m8.jpg

You sampled far more wheels than I did, so I'm curious if my batch
just didn't include true no-attraction spokes.

Cheers,

Carl Fogel

Still Just Me wrote:

Tom_Sherman wrote:

Some people are allergic to nickel, and should stick to utensils without
nickel content.

Say what?

It's true. Some folks can get blisters from handling change, just
from the small percentage of nickel in coins.

It seems like a pretty inconvenient allergy to have.

Chalo

On May 15, 8:46*pm, Still Just Me
wrote:
On Fri, 15 May 2009 18:46:38 -0500, Tom_Sherman

wrote:
Some people are allergic to nickel, and should stick to utensils without
nickel content.

Say what?

As far as I know, nickel allergy results in contact
dermatitis, and is a problem for people who are in
prolonged contact with the metal, for example in
jewelry. Stainless steel is very non-reactive and
nickel does not leach out of it. So stainless is
supposed to not be a problem for the nickel-allergic.
Also if you cook with stainless steel, you aren't
going to wind up eating nickel.

While people should feel free to avoid nickel-containing
stainless steel if they wish, it would be quite difficult to
avoid it completely; you'd have to bring your own silverware
everywhere, among other things.

Ben

On Fri, 15 May 2009 18:44:53 GMT, _
wrote:

On Fri, 15 May 2009 11:12:25 -0600, wrote:

On Fri, 15 May 2009 01:11:08 -0700 (PDT), "
wrote:

I went in the back room and discovered easy access
to 13 (!) wheels. Out come the magnets. One of the
wheels had galvanized spokes and of course the magnet
was strongly attracted to those. A useful control.
Of the remaining 12 wheels with stainless spokes, the kitchen
magnet was very weakly attracted to 2, and not at all
to the remaining 10. The 2 that were slightly magnetic
both had DT 2.0/1.8mm butted spokes. However, I also
tried other wheels with DT butted and non-butted spokes
and found almost no attraction. A few wheels with Asahi and
Wheelsmith stainless spokes had no attraction.

Wheelsmith butted spokes have an obvious transition
diameter where the swaging takes effect and I tested that
part to see if the cold working had rendered them
ferromagnetic at that particular spot. Nope.

I then went back with a very strong magnet removed from
a hard drive, and confirmed that two wheels with DT spokes
were a little magnetic, the rest of the DT spokes were
slightly magnetic, and the Asahi/Wheelsmith spokes weren't
magnetic at all.

For comparison, I tested some other household goods.
Most stainless pans and my old film developing tanks are
non- or very weakly ferromagnetic. The only stainless items
I found to be strongly ferromagnetic were some
kitchen utensils, silverware, and knives, plus a climbing
implement. The ferromagnetic stainless utensils were labeled
"18/0" which of course means 18% chromium and 0% nickel.
This is relevant given the assertion above that higher nickel
content preserves austenitic structure and hence
non-magnetism.

This test is repeatable by anyone, so it shouldn't be hard
for rbt readers to verify for themselves.

Of course, getting a magnet to stick to spokes doesn't
prove they will be heat-annealed at the smoking temperature
of motor oil, but I think paint is a more likely method
for blackening spokes anyway.

Ben

Dear Ben,

Will itty-bitty headphone magnets stick to your no-attraction spokes?

I vaguely remembered some faintly magnetic spokes, so I tested four of
my wheels.

It turned out that the last wheel fooled me and my hard drive magnet.

***

Wheel #1, galvanized spokes, hard drive magnet hangs handily from a
single spoke, satisfying clunk! as it grabs the spoke:

Wheels #2 & #3, aluminum spokes, hard drive magnet hangs, but only
barely and when pressed against two spokes near the crossing--the weak
attraction means that more metal surface is needed to support the hard
drive magnet.

Wheel #4, aluminum spokes, no attraction . . .

Oops!

Very careful testing of wheel #4 showed that the hard drive magnet
pulled sideways when dangled next to a spoke, but so weakly that there
was no hope of sticking to the spoke--it fell off if I let go.


Should have used "jim beam" brand glue.

But an itty-bitty ~6mm round headphone magnet is so small and light
that it sticks on all the spokes, as the photos below show.

Wheel #1 galvanized, hard drive magnet sticks strongly to one spoke:
http://i44.tinypic.com/2v8s2mg.jpg

Wheel #2 aluminum (same with wheel #3), hard drive magnet can barely
stick to the increased surface of two spokes at the crossing:
http://i43.tinypic.com/2sk6t.jpg

Wheel #4 aluminum, hard drive magnet won't stick by itself, even at a
spoke crossing, but it can just cling to a spoke if partly supported
by fishing line:
http://i43.tinypic.com/2mr76m8.jpg

You sampled far more wheels than I did, so I'm curious if my batch
just didn't include true no-attraction spokes.

Cheers,

Carl Fogel

Carl -

- did you happens to miss-pell "stainless" as "aluminum"?

Dear Jay,

Aaargh!

More sleep might help when squeezing tests and posts into the cracks
of the day, but I have an uneasy feeling that it was just native
imbecility.

On the other hand, thanks for the kindest correction I've ever
received.

Cheers,

Carl Fogel

In article
,
Andre Jute wrote:

On May 15, 6:33*am, Hank Wirtz wrote:
RBT SATs time!

"Andre" is to "Scum" as "jim" is to "_____"

a) clown
b) ignorati
c) bull****ter
d) all of the above

Hey, Wirtzie, you know that thing that you do that makes people think
you're a troll? You're doing it again.

Already, put him on the enemies' list.
What is stopping you?

--
Michael Press

In article
,
" wrote:

For comparison, I tested some other household goods.
Most stainless pans and my old film developing tanks are
non- or very weakly ferromagnetic. The only stainless items
I found to be strongly ferromagnetic were some
kitchen utensils, silverware, and knives, plus a climbing
implement. The ferromagnetic stainless utensils were labeled
"18/0" which of course means 18% chromium and 0% nickel.
This is relevant given the assertion above that higher nickel
content preserves austenitic structure and hence
non-magnetism.

This cries out for explanation, as pure nickel is ferromagnetic,
yet alloying with iron results in non-ferromagnetic material.

--
Michael Press

On Fri, 15 May 2009 23:46:31 -0400, Still Just Me wrote:

On Fri, 15 May 2009 18:46:38 -0500, Tom_Sherman
wrote:

Some people are allergic to nickel, and should stick to utensils without
nickel content.

Say what?

Yes - think I first read about this in the New Yorker in the 70's; if such
allergies had by then made it to a relatively mainstream press then they
probably have been known about for longer than that.

Carl -

- did you happens to miss-pell "stainless" as "aluminum"?

Dear Jay,

Aaargh!

More sleep might help when squeezing tests and posts into the cracks
of the day, but I have an uneasy feeling that it was just native
imbecility.

On the other hand, thanks for the kindest correction I've ever
received.


I could, I suppose, have said "You're a retard" - but I don't use his glue,
either.

On May 16, 1:04*am, Michael Press wrote:
In article
,

" wrote:
For comparison, I tested some other household goods.
Most stainless pans and my old film developing tanks are
non- or very weakly ferromagnetic. *The only stainless items
I found to be strongly ferromagnetic were some
kitchen utensils, silverware, and knives, plus a climbing
implement. *The ferromagnetic stainless utensils were labeled
"18/0" which of course means 18% chromium and 0% nickel.
This is relevant given the assertion above that higher nickel
content preserves austenitic structure and hence
non-magnetism.

This cries out for explanation, as pure nickel is ferromagnetic,
yet alloying with iron results in non-ferromagnetic material.

It doesn't require crying out really.
The answer is both basic and complex.
Ferromagnetism is not a linear property of
the alloy recipe ingredients. It depends on
the crystalline structure of the material. In
order to have ferromagnetism, the magnetic
dipole moments of nearby atoms have to
align themselves spontaneously, which means
the spin alignment interaction has to be
energetically favored. Whether this happens
depends on the crystalline structure because
it governs the distance between atoms and the
electron energy band structure.

Iron by itself and nickel by itself may have ferritic
crystalline structures, but it is possible to create
an iron-nickel alloy that has an austenitic structure.
(Austenitic = face centered cubic, ferritic = body
centered cubic). Stainless steel is like that (it has
a lot of chromium, too, of course, but stainless with
nickel appears to remain austenitic).
Cold working the stainless steel can change the
structure, rendering it magnetizable, although I don't
know if it ever gets as ferromagnetic as plain steel.

http://www.scientificamerican.com/ar...agnets-work-on

http://en.wikipedia.org/wiki/Ferromagnetic

Ben

On Sat, 16 May 2009 01:04:36 -0700, Michael Press wrote:

In article
,
" wrote:

For comparison, I tested some other household goods.
Most stainless pans and my old film developing tanks are
non- or very weakly ferromagnetic. The only stainless items
I found to be strongly ferromagnetic were some
kitchen utensils, silverware, and knives, plus a climbing
implement. The ferromagnetic stainless utensils were labeled
"18/0" which of course means 18% chromium and 0% nickel.
This is relevant given the assertion above that higher nickel
content preserves austenitic structure and hence
non-magnetism.

This cries out for explanation, as pure nickel is ferromagnetic,
yet alloying with iron results in non-ferromagnetic material.

Everything is affected by magnetic fields, more or less. For the materials
commonly understood to be "magnetic", that term either means that a magnet
will attract them, or sometimes the quality that have of being turned into
magnets themselves when exposed to a sufficiently strong magnetic field.

It's been some time since I first delved into this stuff, but from what I
recall there are regions called domains, and the magnetic alignment of the
domains is what determines the magnetic qualities of a particular
substance.

Without reading anything further I would hazard a guess that the size of
these domains, and the ease with which their orientation can be changed has
a great deal to do with it. Alloy steels obviously vary in their
structure, and the interactions between the constituents must easily be
complex enough that a simple "A is magnetic, B is magnetic, A+B should be
magnetic as well" may not be what is actually happening.