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How To: Fiberglassing a Trunk Lid

Discussion in 'Car Audio / Security / Electronic Accessories' started by d17type-R, Apr 17, 2007.

  1. d17type-R

    d17type-R Doc Brown says

    Likes Received:
    Sep 21, 2006
    Langley BC
    In the short time that I have been a member of this forum, I have seen a lot of really great ideas done with clean execution because people put their heads together and shared ideas.

    In the spirit of that, I thought I'd offer some of the more intricate details that go into building something truly unique and cool for the trunk of your car.

    Some of you already have experience with Industrial Plastics and Resins, some of you have never even heard of "Unique Whips". So I'm going to approach this from a Beginner's standpoint.

    A couple of basic things you need to know if you don't already are that:

    A) Fiberglass is itchy as hell
    B) Get over it

    With that being said, let's move on to some basic supplies:

    Polyester Resin:
    This polyester resin is used for fabrication of boat hulls, car bodies, and other large surfaces. It has a fast cure cycle and its thixotropic properties reduce runoff and sag on vertical surfaces. It has low viscosity for good wet-out on fiberglass cloth, mat, and roving. It has excellent resistance to impact and to cracking or crazing when flexed.
    (Methyl Ethyl Ketone Peroxide) is the catalyst added to polyester resins and vinyl ester resins. As the catalyst mixes with the resin, a chemical reaction occurs, creating heat which cures (hardens) the resin. Use approximately 1/2 oz per quart of resin. I recommend the use of a MEKP Catalyst Dispenser for accurate measuring and pouring of catalyst.
    Chopped Strand Mat:
    Some other basic supplies to get you started are as follows:
    -Nitrile Latex Gloves (the cheap ones just get eaten through by the Resin)
    -Stir Sticks (Go see the local paint store, or do like I do find a scrap piece of
    CLEAN wood...getting particles in the mixture messes it up)
    -Respirator (some guys like fumes, I like Brain cells)
    -Throw away plastic Quart buckets
    -Throw away Paint brushes
    -Aluminum Foil (the wider the better)
    -Green Painter's "low-adhesion" tape
    -"Mold Release" anti-stick agent for molds (looks like blue shoe polish that
    you apply with a pad)

    Note: The Fumes form the mixture of MEKP and Resin can seriously impair you. If you "Glass", Don't Drive.

    So now that you have the stuff to Fiberglass, You need something to put it on:

    First you need to take the roll of Chopped Strand Mat and tear off workable size chunks in proportion to the piece you'll be working on. For example, a big strip of "mat" won't bend nice and flat around a curve. I recommend taking a cardboard box and sitting down with some gloves on and ripping up what you think will be enough.... then rip up some more. Nothing worse than running out of mat and losing a quart of Resin because you have to sit and tear up some more.
    The reason for tearing the mat is because when you dab the resin into it and there's another piece already laid down, the rough strand ends work like fingers and mesh togehter nicely for a more even finish

    Then, you need to remove the trunk lid from your car. Most on here already know to do the logical sequence and remove all the wires and hardware before loosening off the 4 bolts.

    You need to have a clear area to work in. Lay down something to protect the paint surface of your trunk when you put it down. I keep a decent roll of speaker carpet around for this. Now your work surface can be prepped.

    Take a length of foil that extends past each end of the work surface, and hand form it into all the curves. If you beak through the foil you can patch it with more foil. Once the inside of the lid if "foiled", you can mark out a rough profile of your design with the green tape and a Sharpie....like so:

    More to follow........

    Attached Files:


    YBLEGAL Regular Member w/ Cheese

    Likes Received:
    Aug 9, 2006
    NW Indiana
    damn man, dont mean to bring this back from the dead but u started so strong. can you finish? i'm gonna start making a mold of my center console (i converted auto to manual)
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