Bicycle Mechanics - wheelbuilders: black spoke nipples: steel vs alloy

i just laced a wheel using sapim steel nipples in black using a spokey nipple wrench. i was careful but i still got some scratch marks/abrasions on the nipples. it is nothing to warrant chnaging them out, but after shelling out the extra $$$ for black, and then to have them scratch by simply installing, i am a bit disappointed.

so my question is, are anodized alloy nipples more scratch resistant than steel? i don't know the process of coloring a steel nipple, but i am thinking anodizing is better.

on another note, can nipples differ in outside diameter? i compared a 1.8 vs 2.0 and the outside diameters are pretty much the same. i only ask because the sapim nipples were a tight fit in the semi-aero rim.

I think Sapim's got some issues with the black coloring. I got a good deal on some Sapim spokes a while back because the black on the spokes wasn't holding up too well, the shop had gotten a whole batch of these (for a mt bike wheel so I really didn't care about a cosmetic issue). I'm waiting now on a hubset and plan to use the Sapims again, and the shop mentioned they have some more of these black spokes with the poor black color (but a different batch) but that they were expecting another batch that there was no problem with, so I could have my choice and save some $ if I took the poorer batch. I didn't have an issue with the nipples, tho they're brass, but I'll ask them if they also had that experience when I go in for the hubs and spokes...

ion another note, can nipples differ in outside diameter? i compared a 1.8 vs 2.0 and the outside diameters are pretty much the same. i only ask because the sapim nipples were a tight fit in the semi-aero rim.

That's one of the things that I call a vocabulary expanding experience because it has me muttering every word that I know. If you work in a shop where lots of people have access to spokes and nipples somebody, at some point, is going to get 1.8 nipples mixed in with 2.0 nipples. I can't tell them apart, at least not with just a quick casual look.

If you're working with 2.0 spokes it's aggrivating but not too serious. The smaller nipples simply won't thread on. If you're working with 1.8 spokes, however, the larger nipples will thread on just fine but they won't hold.

well, i had no problem threading the nipple on the spoke as i am sure they are both 2.0. it was getting the nipple through the rim hole which was a tight fit.

in regards to the sapim nipples, i don't think i'll go with them again. compared to the dt spokes, they are more dark gray than black, and then to be so susceptible to scratching. no wonder they are half the price of DTs. maybe they are a bad batch, but i won't risk it again.

for what my experience is worth, i will always go with the same manufacturer from now on, whenever possible.

It's a minor point but I think the "steel" nipples are really brass.

This has also happened to me with DT and Wheelsmith brass nipples. The black coating started to wear off the corners by the time I had finished.

Anodized aluminum nipples are more durable in the coloring but weaker in every other way.

I built a wheelset w/Dt black spokes and black brass nipples that has been ridden all over the world including se Asia etc. and has held up awesome in every way.
Expensive little suckers though.
Never heard of steel nipples...

As for scratches...
http://pikespeakparentnews.freedomblogging.com/files/2008/04/sharpie.jpg

It's a minor point but I think the "steel" nipples are really brass.

+2

They are brass, and brass is a very soft metal - it's simple to melt (low melting-point, mp) and easy to bend and form into shapes. And it does "rust" as well - only it turns green instead of rust-colored. How they made your spoke-nipples black is another matter. But my guess is paint. Aluminum (alloy) is also a soft metal. However it can be anodized into different colors - which won't flake or chip off. Or "Parkerized" -which turns it black. Military weapons made from alloy are Parkerized. This renders them impervious to weather conditions. Parkerized is forever.

When my first set of built wheels had been on the bike a few weeks, I knew I was hooked. Never to lide on a stock wheel again. From the conversation here, I see it's a popular debility. Oh well live and learn. bk

oh yeah, brass, not steel. i had a total brain skip on the translation - :thumb: i live and bought the sapim nipples in germany

thanks for the sharpie tip. i will try it!.

"Military weapons made from alloy are Parkerized." QUOTE.

Only ferrous metals can be PARKERIZED , even then, not all.


"This renders them impervious to weather conditions." QUOTE.

Actually, aside from it's coating, and it's more than a "coating", as it also

penetrates the parent metal, PARKERIZING and oil have an affinity for eah other.

This not only adds to the protection factor but also aids with the lubrication.


"Parkerized is forever." QUOTE.

Nothing is really "forever". (LOL)


Regards,
J T

The mainly-alloy M-16 is parkerized - or whatever they choose to call it. Accurately or not. And you are right regards it going into the metal itself. It does go deep and is not a coating at all. But aside from minor chemical squabbling: My point is/was that alloy nipples would retain a black color. It wouldn't vanish with a small nick or scratch. Brass will easily scratch and remove the coating with it. Then you'd have some lovely green nipples down the road. Oh La La! :D

The mainly-alloy M-16 is parkerized - or whatever they choose to call it. Accurately or not. And you are right regards it going into the metal itself. It does go deep and is not a coating at all. But aside from minor chemical squabbling: My point is/was that alloy nipples would retain a black color. It wouldn't vanish with a small nick or scratch. Brass will easily scratch and remove the coating with it. Then you'd have some lovely green nipples down the road. Oh La La! :D

I've worked with some of the black nipples in the past and I don't think they are painted. They appear to be plated like the silver ones, however the black plating may be more brittle then the silver chrome plating.

Aluminum anodization is a surface coating also and can be removed with scratching, however it is somewhat tougher. It will fade with exposure to sunlight, however and eventually turn brown. Working with aluminum nipples has its own problems since they are more delicate.

Yes - aluminum nipples are said to be more prone to structural failure. At least according to most of those who have published on the subject. But then there are many here who say they've been using aluminum (alloy) nipples in their builds and never had a failure. And some who say the only failure they have had/seen was with the brass nipples.

I'd say the jury is still out.

"Aluminum anodization is a surface coating also and can be removed with scratching" QUOTE.


Anodizing, as does PARKERIZING "grows", into the parent metal. In the case of aluminium, the

"growth", and the "top coat", are of equal value. I do not remember the numbers re PARKERIZING.


Regards,
J T

I built up a front wheel with Aluminum nipples and after a few years they began to break. I will stick with the brass.

I saw some aluminum nipples on a maybe 5 year old Bontrager wheel that were so corroded and soft that they crumbled to powder in the spoke wrench. Can't really see how that risk is worth the minute weight savings.

We don't call 'em weight-WEENIES for nothing! :D

"Aluminum anodization is a surface coating also and can be removed with scratching" QUOTE.


Anodizing, as does PARKERIZING "grows", into the parent metal. In the case of aluminium, the

"growth", and the "top coat", are of equal value. I do not remember the numbers re PARKERIZING.


Regards,
J T

The anodized layer is grown on the metal surface not into the surface. As the layer grows, the aluminum oxide layer - alumina - is an insulator. Acid etching is used to dissolve the alumina layer and allow current access to the unoxidized aluminum under it so that the oxidation process can continue. Fresh aluminum surfaces will eventually form an oxidized layer because aluminum is a slightly reactive metal. However this layer is very thin (a few nanometers) and easily removed.

The alumina is much, much harder than the underlying aluminum but it can still be scratched through to the underlying metal. It is also brittle so the torque necessary to build a wheel can deform the aluminum and crack the anodization.

Alumina has a hardness of 9 on the Moh's scale. Diamond's are 10. It occurs in nature under the names of Ruby, Emerald, and Sapphire. The coloration of these gem-stones comes from impurities. Other, cheaper varieties exist, and are used in industry for grinding other materials. 9 on Moh's is very, very hard. In this form it is also made synthetically and called Carborundum.

Alumina may very well have a hardness of 9.0 on Moh's scale, but we're not checking the hardness of alumina when we wrench on a spoke nipple as the layer is very thin.

hardened steel has a Moh's hardness of 7 or so, titanium is about 6, iron is about 4 or so, and aluminium (depending on how much it has been work hardened) is somewhere between 2 and 3. the thin coating of alumina on top of the aluminium is a factor in aluminium's corrosion resistance, but does very little to protect aluminum from scratching as it is structurally unable to resist the shear stress from the scratching tool because it's only sitting on a chunk of metal at hardness 3. most spoke keys are hardened steel...

"the "growth", and the "top coat", are of equal value." MY QUOTE.


As the top coat "grows", it is by the reduction of the parent metal. This, in effect, makes it

appear as if the process has enfused itself into the PM, the whole now being with less mass,

it being now porous, but much more hard than before.



"It is also brittle so the torque necessary to build a wheel can deform the aluminum and crack the anodization." QUOTE.


This was one of the bugbears re anodized rims, which was noted by JOBST BRANDT -

THE BICYCLE WHEEL 3rd EDITION PAGE 57.

What are the rims on my bike? CAMPAGNOLO RECORD STRADA, Hard Anodized c/w

Aluminium nipples! (LOL)


Regards,
J T

It does protect the aluminum from such entities as oxidation - and does make it stronger to scratches and other abrasions. But yes, it can be compromised. But less than brass. The trade-off is the aluminum spoke-nipple MAY fail sooner than brass.

I'll leave it up to people to make their own decisions. But give them as many facts as we got so it's an educated decision.

Alumina has a hardness of 9 on the Moh's scale. Diamond's are 10..... In this form it is also made synthetically and called Carborundum.
Two points:

1. The Moh hardness scale is non-linear and the difference between a Moh of 9 and a Moh of 10 is huge.

2. Carborundum isn't alumina, its silicon carbide.

Two points:

1. The Moh hardness scale is non-linear and the difference between a Moh of 9 and a Moh of 10 is huge.

2. Carborundum isn't alumina, its silicon carbide.

You are almost correct on the Moh hardness scale. Diamond is about 4 times harder than corundum. Corundum is aluminia while carborundum is entirely different.

As the top coat "grows", it is by the reduction of the parent metal. This, in effect, makes it

appear as if the process has enfused itself into the PM, the whole now being with less mass,

it being now porous, but much more hard than before.


Anodization takes place at the anode of the electrochemical cell. That's where oxidation takes place...not reduction. The aluminum is already at the 0 state and you are adding oxygen to it to make aluminum oxide. Without the acid bath, the oxide layer builds up very quickly and passivates the underlying metal by forming an insulator. The only way to keep the current flowing is to remove some of that oxidization so that the process can continue. It is truly a surface phenomenon and doesn't penetrate into the metal.

You are almost correct on the Moh hardness scale. Diamond is about 4 times harder than corundum. Corundum is aluminia while carborundum is entirely different.
I consider a factor of 4 to be a huge difference, :)

Also the poster said carborundum while refering to alumina which it is not.

Actually carborundum nowadays refers to both alumina and silicon-based materials. Whichever is cheaper to produce. This is usually silicon-based. An example of a mineral that is/was mined commercially for such is garnet(s). They both tally in at a 9 on the Moh's scale. And yes - diamonds are considerably harder than this. But for producing the toughest grinding materials, diamonds are used. Both industrial-grade stones found in nature, and synthetically produced material.

Can anyone tell me what the black coating on the DT brass nipples is?
Seems way more durable than the anodizing on the aluminum nipples, which i dislike anyhow...

I believe this was the premise of this entire thread. Thus far no one has come up with a conclusive answer regards: What is that stuff!?

I've looked on their site and in QBP but they don't say. Some Sveess Seecret?
Maybe that's what they're really doing at CERN.

Yup. It's Dark Matter. Shhhhhhh!

Some black alloy nipples are anodized and some are painted...

Actually carborundum nowadays refers to both alumina and silicon-based materials. Whichever is cheaper to produce. This is usually silicon-based. An example of a mineral that is/was mined commercially for such is garnet(s). They both tally in at a 9 on the Moh's scale. And yes - diamonds are considerably harder than this. But for producing the toughest grinding materials, diamonds are used. Both industrial-grade stones found in nature, and synthetically produced material.
Carborundum is a trademarked corporate name for a company that originally made Silicon Carbide abrasives but now makes several types and compositions of abrasives.

Actually carborundum nowadays refers to both alumina and silicon-based materials. Whichever is cheaper to produce. This is usually silicon-based. An example of a mineral that is/was mined commercially for such is garnet(s). They both tally in at a 9 on the Moh's scale. And yes - diamonds are considerably harder than this. But for producing the toughest grinding materials, diamonds are used. Both industrial-grade stones found in nature, and synthetically produced material.

Carborundum (silicon carbide) and corundum (aluminum oxide or alumina) should not be referred by the same name. They are very different materials. Silicon carbide is a semiconductor while alumina is an insulator. Both are ceramics but each have very different physical properties. Alumina is naturally occurring while silicon carbide is very rare in nature and is entirely manmade.

Garnets are completely different from either. It is a nesosilicates with a lower hardness and contains an divalent cation, a trivalent cation and silicate in an octahedral/tetrahedral framework with [SiO4]4− occupying the tetrahedra. (http://en.wikipedia.org/wiki/Garnet)

Nothin' ticks off a chemist worse than calling two things the same when they aren't:notamused:;)

I defer. I'll only say that one science outfit had alumina so labeled for grinding glass. Ah well. Now back to the "Mystery of the Black Nipple..."