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Thread: Composite Building Newsgroup

  1. #1

    Join Date
    Apr 2016
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    Composite Building Newsgroup

    I am building a Jabiru J230 but I am pretty inexperinced with fiberglass. Unfortunately, there isn't much of a support group for Jabiru builders. Can anyone recommend a newsgroup or other resource for composite building?

    Wayne

  2. #2

    Join Date
    Aug 2011
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    Alabama
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    The KR community is pretty large and from everything I've heard really helpful when it comes to matters of laying down glass.
    The opinions and statements of this poster are largely based on facts and portray a possible version of the actual events.

  3. #3

    Join Date
    Nov 2012
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    1,582
    I am in the process of learning this myself. I lean here or look to these for a lot of help. If you do not know about these wibinars you are in for some very good info. I enjoy watching them if for no other reason then to learn something.

    http://eaavideo.org/video.aspx?v=3618162628001

    Tony

  4. #4

    Join Date
    Sep 2011
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    135
    I've done lots of composite mfg work and can probably answer questions. Built a Pulsar. If you want hands on direction, EAA classes are good. If you want more of a technical education, Andy Marshall's book "Composite Basics" is good.

  5. #5

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    Apr 2016
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    Hello Bob,

    One of my big hang ups is the finishing process. I've taken the EAA's two day seminar on composites and the short one at Oshkosh (a couple of times). These were great for the learning the basics of layups and joints but they didn't go over the finishing.

    One of the first steps in my Jabiru construction manual was to sand down the interioir of the pre made fuselage. They stated this is needed to clean up any rough fiberglass that might cut or scratch you in the building process. I couldn't help myself; I turned a three hour sanding task into 30 hours of turd polishing.

    I'm also concerned that I might leave things too rough and regret it when it is time to do the finishing.

    As as you can imagine, not knowing where I should be on the "make it smooth" or "slap it together" scale has me somewhat paralyzed in my kit building progress. Any advice?

    I also have questions about: fuel tanks, hard points, trim tabs, and other misc items.

    Ill look into getting Andy Marshall's book.

  6. #6
    Byron J. Covey
    Guest
    Quote Originally Posted by Eckertwa View Post
    One of my big hang ups is the finishing process. I've taken the EAA's two day seminar on composites and the short one at Oshkosh (a couple of times). These were great for the learning the basics of layups and joints but they didn't go over the finishing.
    http://curedcomposites.com/finish.html


    BJC

  7. #7

    Join Date
    Mar 2016
    Location
    Rockford, IL
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    30
    Good reply, but for the previous post, it's ok to sand off bits of fiberglass weave that sticks up from the surface. It's not ok to sand into the weave of the cloth or you'll reduce the strength of the glass.

    Bill H.

  8. #8
    cub builder's Avatar
    Join Date
    Nov 2011
    Location
    North Central AR
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    398
    Quote Originally Posted by Eckertwa View Post
    Hello Bob,

    One of my big hang ups is the finishing process. I've taken the EAA's two day seminar on composites and the short one at Oshkosh (a couple of times). These were great for the learning the basics of layups and joints but they didn't go over the finishing.

    One of the first steps in my Jabiru construction manual was to sand down the interioir of the pre made fuselage. They stated this is needed to clean up any rough fiberglass that might cut or scratch you in the building process. I couldn't help myself; I turned a three hour sanding task into 30 hours of turd polishing.

    I'm also concerned that I might leave things too rough and regret it when it is time to do the finishing.

    As as you can imagine, not knowing where I should be on the "make it smooth" or "slap it together" scale has me somewhat paralyzed in my kit building progress. Any advice?

    I also have questions about: fuel tanks, hard points, trim tabs, and other misc items.

    Ill look into getting Andy Marshall's book.
    As previously mentioned, avoid sanding into the weave of the fabric.

    Be fearless when working with fiberglass. There is nothing you can screw up so badly that you can't grind it off and build it up again.

    When finishing, use a cheap rattle can of spray on primer to check your work. If you think it looks good, or you want to see how good (or bad) it looks, spray a light coat of cheap primer over the part. All the imperfections will suddenly come into focus. You're going to sand off the primer anyway, so there is no need to use an expensive primer.

    Pinholes are easy. I brush on a coat of really cheap Rustoleum high fill primer bought at the local autoparts store. Then I brush on some more while it's still wet. Then I brush on some more again while it's still wet until I have a half dried slurry of primer. I squeegee the primer back and forth over the pinholes until it starts to get too thick to work. Let dry for 30 minutes or so, then wet sand with 220 wet. Again, expensive primer isn't required as you will sand off everything except the primer that is left filling the pinholes. After wet sanding, shoot a light coat of cheap rattle can primer as it will show any remaining pinholes. Wet sand the cheap primer back off, and repeat the process if you still have any pinholes. It's inexpensive, and quick.

    Finish on fiberglass is never perfect. You just reach a point where you are tired of sanding and want to fly, so you prime and paint.

    Feel free to peruse my personal web site as there are some areas that cover a lot of glass work that I've done when modifying the KR that I built many years ago. I never put the original photos on line from when I built the plane as photos were still done with film back then, so I didn't take as many and never scanned the ones I have in for the web site.

    -Cub Builder
    Last edited by cub builder; 05-02-2016 at 09:05 AM.

  9. #9
    Byron J. Covey
    Guest
    Quote Originally Posted by cub builder View Post
    Feel free to peruse my personal web site as there are some areas that cover a lot of glass work that I've done when modifying the KR that I built many years ago.

    -Cub Builder
    Nice web site, with lots of interesting items.

    Thanks, Cub Builder.


    BJC

  10. #10

    Join Date
    Apr 2016
    Posts
    10
    Thanks for the two websites. Both will be very helpful.

    I've ordered the Composite Basics book as well as Composite Materials: Fabrication Handbook #1. I found the later on the EAA website.

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