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Date: Sun, 02 Oct 2011 22:27:03 -0400
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Subject: Re: [LML] Re: Wick mechanical connection
From: paul miller <paul@tbm700.com>
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References: <list-5143034@logan.com>

I second Colyn's comments that non-conducting pieces should be prepared =
for static dissipation.   There are also many anti-static primers that =
can be used then finished with normal aircraft topcoats.   An important =
requirement if you do the painting yourself is to make the primer =
continue from the outside surface around the inside mating surfaces =
where it will further conduct to metal or other conductive primer or =
conductive composite.  The military aircraft shop here in Calgary =
explained that the static on the exterior paint will work through the =
topcoat layers easily to the primer and then migrate towards the wicks.  =
If a continuous large circuit is not available, charges build up until a =
gap can be jumped (100,000 volts is not unusual for p-static) and then =
you'll get unexplained  pitting in the paint, pinholes, burn marks, =
static in the radios that can render them completely unusable in snow, =
and flashes are night that look like BBQ igniters where charges are =
jumping gaps.   Of course, some climates like Florida don't get the same =
reaction in fair weather but up north here where it is dry, the =
conditions are magnified.   I had to have a new paint job stripped on =
all the fibreglass components to solve this issue (wingtips, cowls).  I =
found in my research that very few of the southern aircraft painters =
even knew about this issue so it is important to query the paint shops =
on how they will deal with static and how they ensure a continuous path =
from forward surfaces back to the wicks.

Paul Miller
Calgary
On 2011-10-02, at 8:08 AM, Colyn Case wrote:

> I didn't read this whole thread.  Did someone talk about connecting =
from the braid that comes from the hstab to the wick connection?  My =
conclusion was you need a wire from where the braid connects to the =
elevator to the wick socket(s) on the back of the elevator.   Most of =
the static will collect on the leading edge of the hstab, hopefully flow =
through the carbon to your amazingly low resistance (1 ohm?) braid =
connection, across the braid, through the connection to the wire, =
through the wire, into the socket, and out the wick.
>=20
> While you're there consider high resistance conductive paint on all =
fiberglas surfaces that contain a leading edge.   This will allow the =
charge to migrate to the back where hopefully you can figure out a way =
to get it to a wick.  This is the stuff they use on radomes in bigger =
airplanes.  Here's the info on the paint.  As far as I can tell, what =
you want is CA7870.