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                           AeroElectric-List Digest Archive
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                     Total Messages Posted Sat 12/19/20: 1
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Today's Message Index:
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     1. 04:03 PM - Re: Re: Has anyone used very high temp silicone FWF?  (Robert L. Nuckolls, III)
 
 
 
________________________________  Message 1  _____________________________________


Time: 04:03:59 PM PST US
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Subject: Re: AeroElectric-List: Re: Has anyone used very high temp   silicone 
FWF?


>Which one? It seems there are multiple threads going, and some of us 
>are using email (I am, anyway) and others are using the web based 
>list, so I don't know which product you're talking about. The 
>F-B-2000? If so, it would seem that you're probably right, since 
>they're so vague with info. They do claim 1000F+ for the CP 25 WP+ 
>intumescent caulk. Spec sheet attached, showing that the intumescent 
>action happens at 1000 degrees F.
>
>For simple seam sealing, if we're realistic, just about anything 
>would be fine, like Ernest said. The latex based intumescent stuff 
>(CP25WP+) is much cheaper, and ideal for filling empty space around 
>wires, etc in holes, but even that is probably overkill if you use 
>the firesleeve/hose clamp method Bob linked.


    It's been some time since I read the qualification testing
    docs for firewall integrity so I might be in error. I have
    witnessed a couple of tests conducted by the famous Jack
    Thurman and his trusty fire-breathing dragon.

    A mock firewall sheet is fitted with the proposed feed
    thru system. A propane fired burner is positioned a
    few feet off the front side of the firewall. A thermocouple
    is positioned about 6" off the firewall right in front
    of the test article.

    The test setup is bathed in propane powered flame
    sufficient to push the thermocouple reading to 2000
    plus or minus a hundred or so degrees . . . for
    ten minutes.

    After everything cools down, the feedthru is
    disassembled and inspected for depth of penetration
    into the assembly with some criteria for maximum
    allowed charring, etc of the wiring.

    The sealants being discussed are, no doubt, suitable
    for intended purposes of closing voids around pipes
    and/or bundles of wires that penetrate walls
    in structures . . . I'm having trouble wrapping my
    head around any perceived similarities between a
    .030" thick sheet of stainless and a 6" concrete
    or cinder block wall.

    I'll be the first to agree that chances of being
    at-risk from a fuel-fed fire in your airplane
    is really pretty low . . . but not zero. But to
    fill your comfort basket with the knowledge
    nuggets of a completely unrelated approach
    to fire control seems extra-ordinarily
    risky too.

    I'll see if I can scare up a service manual
    or two for some TC aircraft in search of
    a narrative on replacement/modification of
    qualified firewall feed thrus.


   Bob . . .

   Un impeachable logic: George Carlin asked, "If black boxes
   survive crashes, why don't they make the whole airplane
   out of that stuff?"

 

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