Gelcoat question

Discussion in 'Fiberglass and Composite Boat Building' started by doogymon, Oct 31, 2020.

  1. doogymon
    Joined: Jul 2006
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    doogymon Junior Member

    Howdy

    Always wanted to know what the squiggly lines of a dark colour impregnated into the interior of fiberglass boat hulls were and why there? I think I have recently read they are called Webbings and almost look like splatter from a paint brush. A webbing solution is mixed into the final coating of Gelcoat (with wax) to produce the "Webbings" or . Is the above ramblings correct? Reason for question is I will refitting a really neat dinghy soon. A 10' Nomad Camper boat...1963.

    Cheers & thanks

    Doog
     
  2. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member

    Your almost right.

    A "webbing" solution is added inlue of wax. Then it is sprayed thru a gun that is set oddly.

    It is intended to disguise surface irregularities.

    Much cheaper than fairing.
     
  3. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    And the exact amount of webbing solution you mix in, plus the gun adjustments, will allow you to get a wide variety of different looks.

    It can be a splatter finish, fine webbing, or a heavier/bolder silly string effect.
     
  4. Evgenija
    Joined: Nov 2020
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    Location: Macedonia

    Evgenija Junior Member

    Hello,
    I'm new here.
    Can anyone explain to me what the problem is with the gelcoat?

    Sincerely thank you!
    Wish you all the best!
     

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  5. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    Either my eyes are gone. or your defects have not survived the photographic representation.
     
  6. Evgenija
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    Evgenija Junior Member

    Now
     

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  7. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    Frequently the details of the defect don't come through clearly in pics like these. I can see what could be pigment separation, but you need to describe what you see so we know what to look for.

    One of the instructional aids I use is about a dozen 1'×1' panels with purposely made defects. In person the defects are obvious and easy to see in detail. During the current era of Zoom meetings and everything going to pics or videos, the defects are much more difficult to identify on the panels.
     
  8. Evgenija
    Joined: Nov 2020
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    Evgenija Junior Member

    Defects looks lake snowflakes and some of them lake branches. On the parts they look lake colors are dived but when we look closer they look lake I describe above. There are not broken parts. Whole area is smooth there are no signs of retreat.
     
  9. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    Due to where you're located, was the gel coat sprayed, or rolled and brushed.

    There can be a couple of causes, normally too much pigment has been added. If you start with a white base and add pigments to get the correct color, it can become overloaded with pigment and they begin to separate. This is very common when adding black pigment to white gel coat. White pigment is very heavy and black pigment is very light.

    How it's applied can influence how much it may separate too.

    If it's old, or you add thinners, it can cause this too.
     
  10. Evgenija
    Joined: Nov 2020
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    Location: Macedonia

    Evgenija Junior Member

    The gelcoat is bought for brush,but we use styrene or acetone for mix and then we spray.
    We don’t add pigment.
    Suppliers send it ready
     
  11. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    Thinning gel coat formulated for brushing can have results like this.

    There isn't really much you can do at this point to make it look better.

    Occasionally the defects are only near the mold surface and you can sand the surface to remove them. You need to be very lucky for this to be the case though.
     
  12. Evgenija
    Joined: Nov 2020
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    Location: Macedonia

    Evgenija Junior Member

    Thank you very much.I will accept your sugestion tomorrow at work and I will let you know.
     

  13. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    Ondarvr's GRP expertise is a great asset to this website, I doubt you would get better free advice anywhere. Or paid, for that matter !
     
    Blueknarr likes this.
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