[TowerTalk] Re: pencil marks (was element vibration)

[Bill Aycock]

I could be wrong- but I think this may be folklore.  I would like to see a
reference to an accident report, or other documentation, about the
phenomenon.  Pencil lead is primarily a mix of graphite and clay, fired to
high temperature, and has nothing to promote corrosion.

can someone cite a source? Considering the amount of aluminum some members
of this list have in the air,  this needs checking.

Bill- W4BSG


tA 10:38 PM 12/30/1998 -0500, you wrote:
>
>Ron Stone's post reminded me of something that I remember from flying. 
>Never use a lead pencil to draw lines or reference marks on aluminum. 
>The pencil lead will cause the aluminum to corrode and weaken the metal. 
>
>Several emergency landing were traced back to someone using a pencil to
>marking a paint line on the prop tips.  The tips separated in flight and
>caused the engine to have to be shut down due to vibration.
>
>This is not to say that Ron did this.  It just reminded me of times I
>stopped someone from marking the element with a pencil to show how far
>in the elements are supposed to be inserted.  
>
>Sorry for the space just might help someone else later.
>
>Steve
>KD4WIW
>
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-
Bill Aycock   ---   Persimmon Hill 
 Woodville, Alabama, US 35776
 (in the N.E. corner of the State)
      W4BSG   --   Grid EM64vr
        baycock@HiWAAY.net

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