Seized quill stem

I skpped thru this series so forgive me if Iyam redundant.
The back and forth out of JB's that'snot what's happening is best
analyzed atomically. Example, rust is dirt that atomically - figure
the equations - occupies more space with the O2 addition to ferrous
structures - and some H20. There's not enough designed space in there
for the extra atoms.
Heating rust crfumblkes a hard dirt structure that seems here as
almost metallic plating before heat and after as a dirt crust,
Now exavtly what the Aluminum/steel is about I don't know but the
reaction is explained as vigorous and invasive: does it crumble with
heat ? The al/steel material formed under my 544 during salty winter
driving was significantly stronger than 'plated ferrous rust'

linseeed mixed with aluminum antiseize lubes, prevents ion exchange
AND ferrous rust.
copper antiseize works but is less sensual on application.

what doesn't give here is a doubling of two surfaces' oxidation with
every 10 degress hotter - adding atoms to an overcrowded space playing
against the expansion of an outer surface nearest the flame, moving
the outer surface away from the 'dirt' and the inner surface so the
parts are 'freed.'

"Jobst Brandt" wrote in message
...
Graham who? wrote:

[Snip]

Everything is now well greased and back together.

You seem determined to repeat this exercise. Face it; the aluminum
quill stem is dead and should not be exhumed. Get your fork redone
with a threadless steertube.

This is the first time in the thirty year history of that bike that this has
happened. If it takes another thirty years before it happens again then I
will be pushing 90. Hopefully I will still be riding it but certainly not in
the crap wheather we have experienced this winter.

I can see your point on flexing/pumping action and I have been doing a lot
of climbing over the winter in preparation for a trip to the Alps so that
could have exagerated the effect.

As to your heat having no effect theory then I would contend that heating
the aluminium stem would cause it to expand significantly vs the steel
steerer tube and highly compress the aluminium oxide. Reversing the process
on rapid cooling of the stem would have the opposite effect. In my
experience aluminium oxide does not show significant elastic properties so I
would expect the bonding of the layer to be significantly weekened allowing
the stem to be loosened. Fortunately I did not have to go this far. On
removal of the stem it was obvious that the build up of oxide was not that
great but sufficient to give me problems.

Graham.

On 13 Feb, 09:08, "Graham" wrote:
In my
experience aluminium oxide does not show significant elastic properties so I
would expect the bonding of the layer to be significantly weekened allowing
the stem to be loosened.

Well put: exactly the point.
If there were no 'hysteresis' upon heating and subsequent cooling, all
things remaining the same, it wouldn't move a bit. But, to my
experience, it usually does so.

The same as when you have succeded, just by brute force at room
temperature, to turn the damned thing a little bit. At that point you
are sure you will eventually extract it.
In this case you certainly have not removed any atoms from in there,
but simply displaced adjacent layers. You have not destroyed their
tight packing, nor diminished the pressure in there.

Sergio
Pisa

P.s. Graham, when planning your trip through the Alps consult my
friend Allan Nelson's diaries through his site 'Cycling Before Lycra'.
Quite entertaining and informative, in my opinion.

On 13 Feb, 04:12, datakoll wrote:

linseeed mixed with aluminum antiseize lubes, prevents ion exchange
AND ferrous rust.

I'll have to put it in my regular toolkit.

On 13 Feb, 00:25, Jobst Brandt wrote:
Ben C? wrote:
Instead of offering rhetorical questions, how about a positive
suggestion on how to fix it?
As rhetorical as you might have read it, it perhaps deserved a
better answer.
That's exactly what I wrote in another, this time quite positive,
message.
I didn't see how heating aluminum would make it shrink away from
the steel steertube or how heat would loosen aluminum oxide that
had chemically expanded between the stem and steertube.
I think the idea is just that things move a bit relative to each
other and that breaks the bond gluing them together, even if you're
actually making the part that's on the inside bigger.

They are not "bonded" together but have an enormous press fit in the
steel steertube from aluminum oxide development. *Heating the assembly
is difficult because the only exposed (heatable) part is the aluminum
stem that, when heated,

No, the inside of the steerer is accessible via the fork crown.
Heating from this direction and applying a drift and a big hammer to
the end of the stem seems the most logical method and explains the
condition of a stem I was given.

only increases the contact pressure between it
and the steel steertube. *I don't think the theoretical solution
includes melting the stem out of place. *That would do substantial
damage to the head bearings and head tube.

As I mentioned, the contact force from such a corrosion failure is
enough to bulge the steel steertube at "room temperature". *That
effect must also be confronted if the steertube is to be reused.

Jobst Brandt

On 13 Feb, 00:37, Jobst Brandt wrote:
Trevor M. Jeffrey wrote:
Heat has no effect on aluminum oxide inside a steel steertube.
You serious, Jobst? *Isn't this statement a tad too bold?
Instead of offering rhetorical questions, how about a positive
suggestion on how to fix it? *I went through the quill stem failure
with several Cinelli stems and a steel Ritchey stem before the
threadless steertube came along, for which I was glad and have used
ever since with no problems and amazingly greater handlebar
stiffness.
Any intelligent rider would have got either some paint or oil in
there after the third time. *Plugging the bottom of the steerer
mitigates the condensation which causes the corrosion (mixed in with
salts, possilbly from sweating).

The failure occurs from rider sweat

Any salts wether from above or below.

and rain water that has adequate
access at the upper end of the aluminum stem, even though lock rings
on head bearings were equipped with an O-ring so small that it pumps
when the stem swivels from side to side.

Stop dreaming. The water ingress is by condensation which forms 1/2
hour into your morning ride and when you bring the cold bike indoors
every single time. The way to stop this is to use anodised stems and
paint the inside of the steerer. Filling the gap between stem and
steerer with a grease also helps much. Plugging the steerer helps,
although this must be tight. As a finishing touch, gasket sealant can
be used around the stem to locknut junction. This is not a difficult
problem. The metal must be protected against condensation and LINSEED
OIL will do that every time.

It does not come in from the
bottom, although various frame makers offered plugged forks without
any effect believing it came from below. *These were a nice gestures,
recognizing the effect, but not its cause or solution.

The quill stem rocks around from side-to-side above its expander in
the steertube (pumping in fluids) where, in contrast, the
threadless stem is ultimately stiff. *A great feeling.

Jobst Brandt

On 13 Feb, 01:33, AMuzi wrote:
Jobst Brandt wrote:
Trevor M. Jeffrey wrote:

Heat has no effect on aluminum oxide inside a steel steertube.

You serious, Jobst? *Isn't this statement a tad too bold?

Instead of offering rhetorical questions, how about a positive
suggestion on how to fix it? Â I went through the quill stem failure
with several Cinelli stems and a steel Ritchey stem before the
threadless steertube came along, for which I was glad and have used
ever since with no problems and amazingly greater handlebar
stiffness.

Any intelligent rider would have got either some paint or oil in
there after the third time. *Plugging the bottom of the steerer
mitigates the condensation which causes the corrosion (mixed in with
salts, possilbly from sweating).

The failure occurs from rider sweat and rain water that has adequate
access at the upper end of the aluminum stem, even though lock rings
on head bearings were equipped with an O-ring so small that it pumps
when the stem swivels from side to side. *It does not come in from the
bottom, although various frame makers offered plugged forks without
any effect believing it came from below. *These were a nice gestures,
recognizing the effect, but not its cause or solution.

The quill stem rocks around from side-to-side above its expander in
the steertube (pumping in fluids) where, in contrast, the
threadless stem is ultimately stiff. Â A great feeling.

The wooden plugs of old were supposed to keep a crown/column
crack from killing the rider. In my experience they hold
moisture inside the column anyway.

That'll be because the split in the stem was not filled allowing
partial ventilation to atmosphere. A worse situation because the
mosture is unable to vent off. Expanding foam will fill all the
steerer and so none is exposed to moisture.


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

On 12 Feb, 13:37, "Graham" wrote:
Everyting is now well greased and back together.


Fill the steerer with fill n fix expanding builders foam to prevent
salt water ingress and condensation. Caulk the small gap between stem
and locknut with, for example, gasket compound.

On Feb 13, 12:08*am, "Graham"
wrote:
"Jobst Brandt" wrote in message

... Graham who? wrote:

[Snip]

Everything is now well greased and back together.

You seem determined to repeat this exercise. *Face it; the aluminum
quill stem is dead and should not be exhumed. *Get your fork redone
with a threadless steertube.

This is the first time in the thirty year history of that bike that this has
happened. If it takes another thirty years before it happens again then I
will be pushing 90. Hopefully I will still be riding it but certainly not in
the crap wheather we have experienced this winter.

I can see your point on flexing/pumping action and I have been doing a lot
of climbing over the winter in preparation for a trip to the Alps so that
could have exagerated the effect.

As to your heat having no effect theory then I would contend that heating
the aluminium stem would cause it to expand significantly vs the steel
steerer tube and highly compress the aluminium oxide. Reversing the process
on rapid cooling of the stem would have the opposite effect. In my
experience aluminium oxide does not show significant elastic properties so I
would expect the bonding of the layer to be significantly weekened allowing
the stem to be loosened. Fortunately I did not have to go this far. On
removal of the stem it was obvious that the build up of oxide was not that
great but sufficient to give me problems.

Graham.

well, no. why would you expect the bonding tube significantly
different ? as on what grounds ?