Fiberglass Molds?????

Discussion in 'Fiberglass and Composite Boat Building' started by OCEANS_77, Jul 6, 2005.

  1. OCEANS_77
    Joined: Jul 2005
    Posts: 1
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Florida

    OCEANS_77 New Member

    I have a part that is constructed of ABS plastic. The material is too heavy and not strong enough. I need to make a two piece mold so that I can construct multiple fiberglass replicas of the ABS part. So far i've been told that I need to wax the part. I'm not sure what kind of wax. I was expecting to use a good automotive carnuba wax. But i'm not sure if this will work. The part needs to have a perfect glass like finish. I was told that the wax will help when I try to separate the mold and the part. Next to spray the mold with mold release (PCV or something). Then spray it with black gelcoat. I don't know how thick the gelcoat should be. Or how many coats i should use. Also, I have never sprayed gelcoat before. What is the best way to acheive that perfect finish? Then, after the gelcoat has set but remains tacky, add several layers of alternating woven cloth and omnidirectional cloth and adding some kind of wooden structural bracing glassed to the outside. And finnally, when separating the mold I was advised to use compressed air and cold water. Help me with suggestions. this part is nolonger manufactured and I have one of the last ones around. So there is no room for mistakes. Any suggestion you may have or information you can give me is greatly appreciated.

    Thanks
    Travis
     
  2. JEM
    Joined: Jan 2004
    Posts: 299
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    Location: Greensboro, NC

    JEM Senior Member

  3. zember311
    Joined: May 2004
    Posts: 16
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    Location: FL

    zember311 Junior Member

    This site,

    http://www.fbodyaudio.com/articleviewer.php?article=molds.tech

    is a little easier on the eyes and easier to follow for the ( first time ) molders.

    carnuba wax ( YES ) buy the ral deal " mothers " it will last you a lifetime.
    Just give about 30 minutes to haze before you wipe it off, I go with about 5 coats.

    PVA mold release is worth every penny, do one real light coat, as the bottle states, then hit it with a heavy wet coat, the PVA will blend in and form a nice wet surface, when your done with the mold, the PVA reminds me of saran wrap.

    you can use black gelcoat for the mold, tool gelcoat is a bit more scratch resistant, but thats about the only difference between the gelcoat and tooling gel.

    black is a good color to use on the mold if you are using a white gelcoat for the part you are duplicating, this way if there is any thin spots when your spraying the white, you'll be able to see those spots as the black will still be showing through from the mold.

    Molds don't need to be supper thick on gelcoat, I only spray about a credit card thickness on them.

    if your working with a ABS plug, if you wax it then spray on the PVA wet enough to make a nice slick coverage, your mold will come out spotless. if when you spray the PVA you see any pin heads or air bubbles in the PVA either try another coat of PVA or wipe it off with a water soaked rag and try it again, a few cents worth of pva is cheaper then spending a day buffing the mold. IMHO

    here;s a oldie mold I made.
    http://justhulls.tripod.com/mold.html
     
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