Fabric tester

Discussion in 'Pitts' started by cwspilot, Mar 13, 2018.

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  1. Mar 13, 2018 #1

    cwspilot

    cwspilot

    cwspilot

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    Has anyone used the Maule fabric punch tester? What should fabric on the Pitts test out to?
     
  2. Mar 13, 2018 #2

    will moffitt

    will moffitt

    will moffitt

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    About 5 years ago, my first starduster inspection the mech had one. Don't know if he had ever used it judging from the way he handled it. Checked oK of course. At the time my hanger mate had some old t-craft frames. They were older than Methuselah's dog but not cotton. I asked him to check one of them as they were rags. Checked OK. I was not impressed. My opinion was if it failed it would be obvious to the eye. But I can stand to learn something.

    will
     
  3. Mar 13, 2018 #3

    DanSalcedo

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    80 lbs new for grade A cotton, 70% used, its used if its been installed on the plane.
    So, 56lbs.
    Polyfiber is much stronger, but still test to 56 lbs.

    The Maule will leave an indentation that is all most gone in a few days. Old paint may crack or ringworm. Test on upper surfaces in the darker paint. I,ve only have failures in Cotton, never Dacron but not saying it cant.
    Dan
     
  4. Mar 14, 2018 #4

    Lotahp1

    Lotahp1

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    If you look Cotton and I believe Razorback (fiberglass cloth based old system) are the ones that are “punch tested”. From all the ceconite and stits books I’ve read I have never seen them give a punch test method as a way to test airworthiness. Please share info if you indeed found info where they recommend a punch test.
     
  5. Mar 14, 2018 #5

    DanSalcedo

    DanSalcedo

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    Manual says its an aid. I'd much rather tell a lawyer I used a tester than I pushed it with my knuckle to test airworthiness. Like I said, never tested a bad Polyfiber yet, only cotton. Most of my customers don't want me to cut a 1" strip out of the plane to check its strength.

    So to me its a reasonable test to make sure the fabric is good without any damage to the fabric and gives me some assurances.

    Dan



    Appendix F from polyfiber manual pg 103

    The IA can use a Maule Fabric Tester
    on the bare fabric as an aid to see if
    there is UV damage.
    Warning: AC 43.13 - 1B states
    that a Maule Tester is not
    approved for determining
    airworthiness; it is only an
    aid. Also Maule Testers only
    give an accurate reading on
    bare fabric. It does no good
    to “punch” painted fabric;
    you are measuring the com-
    bined strength of the paint and
    fabric. The FAA only cares
    about the fabric. To use the
    Maule, push until it reads 56
    pounds; no need to push fur-
    ther and punch a hole in the
    fabric unless the IA is seeking
    additional business repairing
    your unnecessary holes.


     
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  6. Mar 14, 2018 #6

    planebuilder

    planebuilder

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    The important point is bare unpainted fabric! Painted in some cases will aid failure. If it does then remove the paint and retest, good chance it will pass.
     
  7. Mar 14, 2018 #7

    cwspilot

    cwspilot

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    Thanks for the input everyone. Much appreciated!
     

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