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Thread: SB #7 Structural tests?

  1. #1
    jonstark's Avatar
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    Default SB #7 Structural tests?

    SB #7 refers to structural tests the manufacturer was to perform to ascertain whether the strength of epoxy using microballoons would be comparable to that using cotton flox. I can't find any further reference to these tests and wonder whether they showed acceptable strength for wing applications using microballoon thickened epoxy.

    questions...
    1. Is there a visual way to tell if the epoxy used in wing construction was thickened with flox or microballoons?
    2. Is there any reference to the test results?
    3. Is a wing made with microballon thickened epoxy acceptable?

    thanks!
    jon

  2. #2
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    Default Re: SB #7 Structural tests?

    Microballons are a non-structural sandable filler, you would not use them to build
    a wing, or other structure. If you have a wing built with them, it would not be
    airworthy.

    Regards,
    Jeff Hays

  3. #3
    jonstark's Avatar
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    Default Re: SB #7 Structural tests?

    Quote Originally Posted by n85ae View Post
    If you have a wing built with them...
    How can I tell?

    jon
    Kitfox IV 1050, C180. Now I have two backcountry planes! WooHoo!

  4. #4
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    Default Re: SB #7 Structural tests?

    You could probably see the cotton fibers in the cured joints with magnifying
    glass, if you have a kids cheap microscope you could surely see the fibers
    with it.


    Here's a link to some info on fillers:

    http://members.eaa.org/home/homebuil...struction.html

    Here's a link, which seems to say it's ok, BUT I would not build a wing with them:

    http://kitfox.lazair.com/Service_Letters/sl21.htm

    John McBean at Kitfox could probably say yes/no to use on a Kitfox.

    Regards,
    Jeff

  5. #5
    jonstark's Avatar
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    Default Re: SB #7 Structural tests?

    Your second link is key. It refers to a batch of serial numbers rather than the SB which calls out a period of delivery dates that might have been delivered with balloons in lieu of flox.

    I fell within the delivery dates but now find this kit was outside the serial number batch.

    Whew!

    Thanks for the info.
    jon
    Kitfox IV 1050, C180. Now I have two backcountry planes! WooHoo!

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