Is it better to sand a resin rich repair or leave it alone

Discussion in 'Fiberglass and Composite Boat Building' started by sbklf, Jul 25, 2007.

  1. sbklf
    Joined: Feb 2006
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    sbklf Junior Member

    I am working with epoxy and have been sanding excess resin puddled at the bottom of 90 degree corners. I thicken resin applied to vertical surfaces but dont have mix ratios down yet. When sanding I am careful to stop when I hit glass and add a layer if I cut into it too deep. I know resin rich repairs are weak but is it better to leave it alone?
     
  2. jimslade
    Joined: Aug 2005
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    jimslade Senior Member

    Resin rich repairs are only weak with polyester resin. Epoxies are usually flexible enough to discount this probability.
     
  3. sbklf
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    sbklf Junior Member

    Thats good to hear, Thanks
     
  4. johnnyv
    Joined: Mar 2007
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    johnnyv Junior Member

    Not true, improper mix ratios with epoxy give a weaker product. 5% by weight off on one of the components is usually fine, with greater variations tensile strength degrades significantly.
     
  5. alan white
    Joined: Mar 2007
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    alan white Senior Member

    I believe the reference was to cured resin to glass ratio. Polyester has little strength on its own. More resin than is needed to saturate the cloth simply adds weight and a tendancy to crack under stress or hot/cold cycles. Epoxy has some elasticity and performs a structural role without cloth.

    Alan
     
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  6. johnnyv
    Joined: Mar 2007
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    johnnyv Junior Member

    Ah i was seeing that as resin as in the resin component also mix ratios was related to filler.
    I shouldn't skim in the morning :eek:
     

  7. the1much
    Joined: Jul 2007
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    the1much hippie dreams

    how thick is the puddle?, and where is it?,inside hull, outside on deck?, . if its noplace of any concern and not thick,,leave it,, if over an 8th inch thick grind down ta close nuff lol,if going over with another layer of something grind it away alwaYz no matter what kind it is.
     
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