John

The grey stuff coming out of your hinge is aluminum oxide.  As the corroded
surface inside the hinge is abraded by the pin when the hinge flexes the
result is a black powder that gets lubricated by precipitation or whatever
and flows out of the hinge onto your pretty white painted glass surface.
Over time the corrosion results in shape change inside the hinge and the
hinge gets sloppy.

One problem in my opinion with the Teflon is that it tends to "work" and
flow under load.  Therefore, the hole in the Teflon tubing will gradually
become egg shaped and the pin may eventually wear its way through the Teflon
sleeve on the load side. Also you have to use a smaller pin - weakening the
apparatus.

The best answer I know of is to use graphite hinges with nylon bearing.
Down side is you have to remove the current hinges and replace them.

I have a definite bias and an economic interest in a product called
Carbinge.  It is a graphite piano hinge with a nylon bearing.  We have been
making this product for about 8 years and have done tests showing that there
is little to no wear over at least a million cycles with Carbinge.  Also the
shear strength of Carbinge is rated at 3,000# per lineal foot with a 100%
safety factor, and even at 6,000# per foot you only reach a limit load
(meaning that the hinge will not fail - only the pin will distort.)
Hundreds of Lancair pilots and other experimental aircraft builders have
used Carbinge and I do not have any reports of wear or failure of the
product.  I do have reports of how well the product is holding up in
aircraft with up to 800 hours.  

See the website for more information:

www.carbinge.com

Regards,
John Barrett

-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of
Marvin Kaye
Sent: Monday, February 19, 2007 1:20 PM
To: lml
Subject: [LML] Re: Outboard elevator hinge bleeding

Posted for "Jim Nordin" <panelmaker@earthlink.net>:

  I asked someone at Lancair years ago about this problem and his (name
  withheld) answer was simple.
  Misalignment is a problem with two hinges on the same elevator. Put one
  hinge on that is the length of the elevator attachment (26.75") and make
  sure it's straight ... not wavy in any axis. That was a statement from a
  previous support person there.
  
  I think the Teflon is the best fix for installed hinges. And you might
take
  a look to make sure the best job of alignment has been done. The fit can
be
  improved without damage to the paint job if you're careful.
  Jim
  
"""
  Posted for John Spry <spry@paradise.net.nz>:
  
   I've done 30 odd hours in my recently completed 320 (small tail) and
  notice
  grey streaks (aluminium I think) coming from the outboard elevator hinges
.
   Everything seems tight - has anyone got any ideas what may be causing it
  and
  the best fix.
   
   Thanks
  
  

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