white thing on rim around spoke holes/nipples?

On Wed, 29 Jun 2016 23:09:26 +0200, Emanuel Berg
wrote:

AMuzi writes:

It's aluminum oxide, a corroded residue which
was once metal, but now at a lower
energy state.

The aluminum of the rim reacts to the spoke
nipples in time? Or is it sensitive to dirt and
moisture that just sticks in and around the
holes and nipples?

What do you do about it?

Keep clean?

The wire brush worked but not without effort
and I could see that in the nooks the aluminum
oxide remained...

Aluminum alone is essentially non-corrosive, but in the presence of
many other metals, and an "electrolyte", it forms a tiny battery and
results in galvanic corrosion. The only complete solution is to
insulate the two metals.

Electrolyte is any liquid that will carry an electric current. Pure
water is not but water with almost any chemical, commonly salt, is.

Having said that in actual practice if you clean the corrosion as
much as possible and put a drop of oil or perhaps a smear of grease on
it will likely be sufficient for some years.

One site recommends Marvel Mystery Oil co clean aluminum corrosion.
But I don't know whether it is available world wide.
https://www.youtube.com/watch?v=MJ-uf4YyeHI

The people that make Naval Jelly (to clean rust) also, I believe, make
an Aluminum Jelly to clean aluminum, but unless you are prepared to
dismount the tire and rim tape so that the wheel can be really cleaned
I think I'd be reluctant to use harsh chemicals.
--
cheers,

John B.

On 6/29/2016 6:26 PM, Jeff Liebermann wrote:
On Wed, 29 Jun 2016 06:05:50 +0200, Emanuel Berg
wrote:

What is it and how do you remove it? Only from
a very good position I got it away with a wire
brush...

The white thing? That's the price tag. I'm not sure why someone
would put it around a spoke hole, but it should come off with some
solvent or "Goop Off" oil. A wire brush will scrape off the surface
anodizing from the rim, and damage the rim finish. If you must
scrape, use a soft plastic or soft boar bristle hair brush.

Is there any chance he's talking about some sort of rim tape or rim strip?


--
- Frank Krygowski

Frank Krygowski
writes:

Is there any chance he's talking about some
sort of rim tape or rim strip?

The rim tape doesn't seem to be affected.

As I understood it from AMuzi and John B., the
nipples are brass, the rim is aluminum, add
water with in particular salt to form an
electrolyte, this turns the whole thing into
a *battery* (!) with galvanic corrosion where
the aluminum looses energy and turns into
something else (?) - the white stuff.

Question 1: Right?

Question 2: Why are the nipples brass? Is that
cheaper and/or more formable than aluminum?

--
underground experts united .... http://user.it.uu.se/~embe8573
Emacs Gnus Blogomatic ......... http://user.it.uu.se/~embe8573/blogomatic
- so far: 55 Blogomatic articles -

On 6/30/2016 6:08 AM, Emanuel Berg wrote:
Frank Krygowski
writes:

Is there any chance he's talking about some
sort of rim tape or rim strip?

The rim tape doesn't seem to be affected.

As I understood it from AMuzi and John B., the
nipples are brass, the rim is aluminum, add
water with in particular salt to form an
electrolyte, this turns the whole thing into
a *battery* (!) with galvanic corrosion where
the aluminum looses energy and turns into
something else (?) - the white stuff.

Question 1: Right?

Question 2: Why are the nipples brass? Is that
cheaper and/or more formable than aluminum?


1. Maybe galvanic corrosion with the nipple, maybe with a
steel rim insert. But corrosion nonetheless.

2. Well, the wheelbuilder's reasons may include strength,
cost or 'because we have brass nipples'. As with #1 above,
here we are, it's corroded for whatever reason. Your problem
is more whether to ignore it, clean it or replace it I think.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Wed, 29 Jun 2016 18:43:23 -0700, Jeff Liebermann
wrote:

On Thu, 30 Jun 2016 00:51:05 +0200, Emanuel Berg
wrote:

Jeff Liebermann writes:

What is it and how do you remove it?
Only from a very good position I got it away
with a wire brush...

The white thing? That's the price tag.
I'm not sure why someone would put it around
a spoke hole, but it should come off with
some solvent or "Goop Off" oil. A wire brush
will scrape off the surface anodizing from
the rim, and damage the rim finish. If you
must scrape, use a soft plastic or soft boar
bristle hair brush.

I have the common hair, nylon, brass, and steel
brushes, with steel wool, Svinto, and emery.
Perhaps just cloth and alcohol can take some of
it away long with some dirt...

So much for my humor.


No! We read it and we smiled, gently. And then went on :-)


As others have mentioned, you may have some aluminum oxide corrosion.
There are a variety of mechanisms that will attack aluminum, including
some "cleaners". Galvanic action will also cause corrosion such as
between a brass spoke nipple and the aluminum rim:
http://www.totalmateria.com/page.aspx?ID=CheckArticle&site=ktn&NM=187
I can't tell from here which one has trashed your rim. A photo would
be useful. You may need a microscope to see any cracks. If the spoke
hole looks damaged, the spoke nipple might rip through the enlarged
and weakened hole when put under tension.

You might also want to take a look inside:
http://farm6.staticflickr.com/5470/8944382412_857779a6b7_k.jpg

The problem is that to produce aluminum oxide, some aluminum must
disappear to produce the oxide. That results in pitting, cracking,
and weakening of the aluminum. If you actually manage to clean off
the oxidation, you'll probably find a damaged surface.

Scroll down to the 3 photos of damaged rims:
http://www.totalmateria.com/page.aspx?ID=CheckArticle&site=ktn&NM=187

As for cleaning, there are a variety of potions that claim to work:
https://www.google.com/search?q=aluminum+oxide+cleaner
Most contain phosphoric acid. For example:
http://www.loctiteproducts.com/p/s_trmt_alum/technical-data/Loctite-Aluminum-Jelly.htm
http://www.aircraftspruce.com/catalog/cspages/alumiprep.php
If you just want to clean off the oxide crust, acetic acid, in the
form of white vinegar should work. However, it's not a very strong
acid, takes a long time, and will ruin a rim with polished aluminum
finish.
--
cheers,

John B.

On Thu, 30 Jun 2016 13:08:18 +0200, Emanuel Berg
wrote:

Frank Krygowski
writes:

Is there any chance he's talking about some
sort of rim tape or rim strip?

The rim tape doesn't seem to be affected.

As I understood it from AMuzi and John B., the
nipples are brass, the rim is aluminum, add
water with in particular salt to form an
electrolyte, this turns the whole thing into
a *battery* (!) with galvanic corrosion where
the aluminum looses energy and turns into
something else (?) - the white stuff.

Question 1: Right?
Answer: Probably


Question 2: Why are the nipples brass? Is that
cheaper and/or more formable than aluminum?

Answer: A: Brass has a higher sheer modulus ( stronger threads) than
aluminum
B: It has worked perfectly well for a hundred tears or more.
except in rare cases.

--
cheers,

John B.

On Wednesday, June 29, 2016 at 12:05:52 AM UTC-4, Emanuel Berg wrote:
What is it and how do you remove it? Only from
a very good position I got it away with a wire
brush...

--
underground experts united .... http://user.it.uu.se/~embe8573
Emacs Gnus Blogomatic ......... http://user.it.uu.se/~embe8573/blogomatic
- so far: 55 Blogomatic articles -

https://www.google.com/#q=practical+...anic+corrosion

the practical machinist is a resource for berg.

uh the white oxide or OH compound should not be on a bicycle rim. The rim should be made of an aluminum type not subject to common galvanic corrosion.

aluminum instantly forms AlO aluminum oxide thus soldering it uses a special rod.

I have an older glasses frame of solderable aluminum...type 2 ? or 3 ?
very rare. Its hidden lest the optical vampires come by...

that white is INORGANIC and so does not as may try esp with the fork jamming problem using organic solvents from petroleum sources.

Phosphoric acid is most commonly used metallic cleaner

linseed oil on spoke threads insulates two metals from passing ions back and forth like in a battery...galvanic corrosion....and gives a low torque hold in the threads

On 01/07/16 03:18, John B. wrote:
On Thu, 30 Jun 2016 13:08:18 +0200, Emanuel Berg
wrote:

Frank Krygowski
writes:

Is there any chance he's talking about some
sort of rim tape or rim strip?

The rim tape doesn't seem to be affected.

As I understood it from AMuzi and John B., the
nipples are brass, the rim is aluminum, add
water with in particular salt to form an
electrolyte, this turns the whole thing into
a *battery* (!) with galvanic corrosion where
the aluminum looses energy and turns into
something else (?) - the white stuff.

Question 1: Right?
Answer: Probably


Question 2: Why are the nipples brass? Is that
cheaper and/or more formable than aluminum?

Answer: A: Brass has a higher sheer modulus ( stronger threads) than
aluminum
B: It has worked perfectly well for a hundred tears or more.
except in rare cases.

I do have the same 'problem' on my commuter. Most likely due to salt in
the winter. But, well, it is the slut bike, so who cares?

On 7/1/2016 12:22 AM, Tosspot wrote:
On 01/07/16 03:18, John B. wrote:
On Thu, 30 Jun 2016 13:08:18 +0200, Emanuel Berg
wrote:

Frank Krygowski
writes:

Is there any chance he's talking about some
sort of rim tape or rim strip?

The rim tape doesn't seem to be affected.

As I understood it from AMuzi and John B., the
nipples are brass, the rim is aluminum, add
water with in particular salt to form an
electrolyte, this turns the whole thing into
a *battery* (!) with galvanic corrosion where
the aluminum looses energy and turns into
something else (?) - the white stuff.

Question 1: Right?
Answer: Probably


Question 2: Why are the nipples brass? Is that
cheaper and/or more formable than aluminum?

Answer: A: Brass has a higher sheer modulus ( stronger
threads) than
aluminum
B: It has worked perfectly well for a hundred tears or
more.
except in rare cases.

I do have the same 'problem' on my commuter. Most likely
due to salt in the winter. But, well, it is the slut bike,
so who cares?


Slut's an excellent moniker for my filthy winter bike,
thanks for that.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On 01/07/16 14:13, AMuzi wrote:
On 7/1/2016 12:22 AM, Tosspot wrote:
On 01/07/16 03:18, John B. wrote:
On Thu, 30 Jun 2016 13:08:18 +0200, Emanuel Berg
wrote:

Frank Krygowski
writes:

Is there any chance he's talking about some
sort of rim tape or rim strip?

The rim tape doesn't seem to be affected.

As I understood it from AMuzi and John B., the
nipples are brass, the rim is aluminum, add
water with in particular salt to form an
electrolyte, this turns the whole thing into
a *battery* (!) with galvanic corrosion where
the aluminum looses energy and turns into
something else (?) - the white stuff.

Question 1: Right?
Answer: Probably


Question 2: Why are the nipples brass? Is that
cheaper and/or more formable than aluminum?

Answer: A: Brass has a higher sheer modulus ( stronger
threads) than
aluminum
B: It has worked perfectly well for a hundred tears or
more.
except in rare cases.

I do have the same 'problem' on my commuter. Most likely
due to salt in the winter. But, well, it is the slut bike,
so who cares?


Slut's an excellent moniker for my filthy winter bike, thanks for that.

Now the Princess on the other hand, dry miles (of course) only, not a
smidgen of dirt of the drive train, I shudder to think of a missed
service, and of course, closeted in my bed every winter night.