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  1. #1
    Join Date
    18th January 2009
    Location
    Central WI
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    480

    Quik-Tube, Glass Mandrel or Glassed Body Tube?

    Some 8'' concrete forms waiting in the garage to be turned into an upscaled scratch built version of my L1 rocket.

    All tubes will fit real nice together with just a veil layer of glass or so on them but will be fairly heavy as the cardboard tubes themselves are about a pound per foot minus whatever the veil layer might weigh.

    Now, I have been thinking about a veil layer over the tubes, then a mat layer over that (for strength) then another surface veil layer of glass. Then soak/erode with pressure washer or by whatever means the cardboard tubes away leaving just glass body tubes.

    Locally available Bondo glass (6~9oz?) cloth and mat is what I'll be using unless I find better local source.

    All to be done with ProLine Epoxy not Polyester BTW.

    Objective is to keep it light enough for a 54mm K805 + 3x 38mm J??? peripherals but strong enough for a low end 75mm "M' someday.

    I know this has been done before, I just haven't found a good write up on it.

    Anybody ever hosed the cardboard out of glassed tubes with any success? Caveats? Gotchas?

    Thanks in advance for any helpful input you might have.

    Here's an R&D version of the rocket I have in mind.
    Negate all weights and altitudes for obvious reasons.

    Attached Files Attached Files
    Scott Broderick
    -TRA 11694 L2-

    "...look around you, can you fabricate some sort of rudimentary lathe?..." Guy, from Galaxy Quest

  2. #2
    troj's Avatar
    troj is offline Wielder Of the Skillet Of Harsh Discipline, Potentate of Perilous Pans TRF_ADMIN.png
    Join Date
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    Don't use Bondo mat with an epoxy resin -- you won't get the strength you expect. There's a binder in the mat that holds the fibers together, which is specifically designed to dissolve in a polyester resin. Without it dissolving, you won't properly wet out the fibers.

    There are mats out there designed to work with epoxy resins, but I don't know off the top of my head who carries them.

    Removing the cardboard isn't a huge deal; I've seen it done, never done it myself. Just soak it in a tub of water until it's soggy, then pull it out.

    -Kevin


  3. #3
    Join Date
    18th January 2009
    Location
    Central WI
    Posts
    480
    Quote Originally Posted by troj View Post
    Don't use Bondo mat with an epoxy resin -- you won't get the strength you expect. There's a binder in the mat that holds the fibers together, which is specifically designed to dissolve in a polyester resin. Without it dissolving, you won't properly wet out the fibers.

    There are mats out there designed to work with epoxy resins, but I don't know off the top of my head who carries them.

    Removing the cardboard isn't a huge deal; I've seen it done, never done it myself. Just soak it in a tub of water until it's soggy, then pull it out.

    -Kevin
    Wow! Now that's a gotcha I never saw coming. I think I'll look around a bit and see if I can find a better selection of fiberglass around here.

    I'm glad I asked.

    Thanks Kevin.
    Scott Broderick
    -TRA 11694 L2-

    "...look around you, can you fabricate some sort of rudimentary lathe?..." Guy, from Galaxy Quest

  4. #4
    Join Date
    20th January 2009
    Location
    Honolulu, Hawaii
    Posts
    120
    check these guys out...top quality glass verry tight weave.
    http://www.fiberglasssite.com
    their glass works well with poly resin and epoxy.
    The menace formerly known as "sandog"
    NAR L2

  5. #5
    Join Date
    19th January 2009
    Location
    NYC area
    Posts
    176
    Quote Originally Posted by troj View Post
    Don't use Bondo mat with an epoxy resin -- you won't get the strength you expect. There's a binder in the mat that holds the fibers together, which is specifically designed to dissolve in a polyester resin. Without it dissolving, you won't properly wet out the fibers.

    There are mats out there designed to work with epoxy resins, but I don't know off the top of my head who carries them.

    Removing the cardboard isn't a huge deal; I've seen it done, never done it myself. Just soak it in a tub of water until it's soggy, then pull it out.

    -Kevin
    Excellent info, I'm glad you shared on the bondo mat
    John F
    Level 2 NAR #88935 Tripoli 12209
    MDRA #36
    John's Spot

  6. #6
    Join Date
    11th April 2009
    Location
    SF Bay Area
    Posts
    857
    This is a link to a different method but there is a lot of good information.

    http://www.vatsaas.org/rtv/construct.../tubeform.aspx


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