From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Fav Anti-seize?
Date: 31 May 2001 21:26:43 GMT

Effective anti seize lubricants must contain soft metal particles
because liquid lubricants will, in time, be displaced by preload,
temperature cycling alone causing enough fretting to displace oil and
grease.  For that reason in high vacuum applications, where liquid
lubricants are not permitted due to their volatility, screws are
silver plated, silver being the lubricant between metals that would
otherwise gall.  Therefore, many anti seize lubricants are so only in
name, being made entirely of oils, some having Teflon that will
extrude from many high pressure interfaces.

I don't know of any joints in a bicycle that require this, nor have I
seen failures that would have been prevented by anti seize lubricant.
I think it just sounds high tech and important to use such materials.
The only such interface that comes to mind is the tapered square press
of pedal cranks on the BB spindle, and that has not shown galling in
spite of fretting that occurs.

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Fav Anti-seize?
Date: 1 Jun 2001 18:37:36 GMT

Patrick Lamb writes:

>> Effective anti seize lubricants must contain soft metal particles
>> because liquid lubricants will, in time, be displaced by preload,
>> temperature cycling alone causing enough fretting to displace oil
>> and grease.  For that reason in high vacuum applications, where
>> liquid lubricants are not permitted due to their volatility, screws
>> are silver plated, silver being the lubricant between metals that
>> would otherwise gall.  Therefore, many anti seize lubricants are so
>> only in name, being made entirely of oils, some having Teflon that
>> will extrude from many high pressure interfaces.

> Say what?  Temperature cycling causes fretting?  Fretting displaces
> oil and grease?  What application are you talking about?

Head bearing failure is a case of fretting displacing grease and
causing repeated welding of the balls and races to cause the dimples
in the races.  That is a classic example of lubrication failure from
fretting.  Most steel screws in aluminum experience thermal fretting
and lubricant displacement causing galling of originally lubricated
interfaces.

> It's all about vapor pressure.  Most low-viscosity fluids, including
> oil, will evaporate given time (or a vacuum).  Grease may or may not,
> depending on the temperature.

Well my Sturmey Archer hub stayed lubricated for 20 years without
evaporating.  I think you have these things a bit confused.  Fretting
displaces lubricants.  That's why press fit gears submerged in oil
develop rouge in the press fit.

> BTW, we always used vacuum grease for vacuum setups.  With a diffusion
> pump (since displaced by turbine pumps, except in poor grad student
> labs), it was good down to 1E-6 torr.  Unless you flamed it -- not
> recommended for bicycles.

Your vacuum jive has no bearing on anti seize lubricants.  I only
mentioned it because silver is a good anti seize metal and is used
where no oils are permissible, 1E-6 or otherwise.

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Fav Anti-seize?
Date: 4 Jun 2001 18:43:30 GMT

Gary Muntz writes:

>> I don't know of any joints in a bicycle that require this, nor have I
>> seen failures that would have been prevented by anti seize lubricant.
>> I think it just sounds high tech and important to use such materials.

> I'm trying to follow common advice like "grease every thread", "grease
> the seatpost/stem", etc. These are really anti-seize applications rather
> than lubrication applications, right? Then I figure I should use the
> right tool for the job.

I think you are broadening the definition of anti seize.  Seize in the
primary sense is about galling, or as is often used, cold welding (it
isn't cold).  The applicatons you mention are more corrosion
resistance and common lubrication even for a tight joint.  Anti seize
is effective where metals would otherwise weld.  If this weren't the
case, a lubricated nut and bolt would not tighten or unscrew wihtout
welding.  The example of high vacuum applications, where both surfaces
must be free of contaminants (lubricants), makes this clearer.

>> Effective anti seize lubricants must contain soft metal particles
>> because liquid lubricants will, in time, be displaced by preload,
>> temperature cycling alone causing enough fretting to displace oil and
>> grease.

> Say - is the lithium in "white lithium grease" the soft metal you
> mention?  In that case, maybe what you're saying is a generic grease
> like that is adequate for bike applications requiring lubrication
> and/or anti-seize?

No. The lithium is its oxide, not the metal.  My experience with this
grease, both Campagnolo and a commercial brand was that it plymerized
into tar like vegetable oil, turning dark brown and gummy.  That is
why I wouldn't us it as bearing grease.

Jobst Brandt      <jbrandt@hpl.hp.com>