Secondary bonding concerns

Discussion in 'Fiberglass and Composite Boat Building' started by pescaloco, Nov 11, 2014.

  1. pescaloco
    Joined: Feb 2006
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    Location: so. california

    pescaloco Senior Member

    Hey guys

    I wanted to get some feedback on making repairs to DCPD blend and aged Vinyl Ester resin. I do fiberglass repairs and gelcoat work and am partial to Vinyl Ester resin. I use epoxy when I feel it is prudent but really prefer the speed and ease of the VE and the compatibility with Gelcoat

    My concern is am I making a quality repair or secondary bond when using VE
    My concern got me browsing the net and I came across an article that I will quote a couple lines

    There are distinct disadvantages to using Vinylester as well:


    It also has difficulty in bonding dissimilar and already-cured materials.

    It is not unusual for repair patches on Vinylester resin fibreglass to delaminate or peel off and
    many Vinylester hulls suffer delamination of the hull skins from core and bulkhead substrates.

    As Vinylester resin ages, it becomes a different resin (due to it's continual curing as it ages) so new
    Vinylester resin sometimes resists bonding to older Vinylester, or will bond and then later peel off.

    Vinylester resins bond very well to fibreglass, but offer a poor bond to Kevlar and carbon fibre due
    to the nature of those two more exotic fibres.

    Thank you for your feed back
     
  2. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    Where did you get those quotes from, was it from a resin company, or from another source?
     
  3. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Agreed, it sounds like sales "fluff" more then anything else. Most boats are full of mechanical not chemical bonds, so I guess, with this logic, they'll all be falling apart soon? Simply put, mechanical bonds just require the surface is clean and well toothed. Yeah, sure on a technical level they'll not be quite as good as a chemical bond, but you can accommodate this with repairs, tabbing, schedule, etc.

    Maybe it would be simpler to tell us what you're trying to do, on what, etc.
     
  4. SukiSolo
    Joined: Dec 2012
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    SukiSolo Senior Member

    I have successfully repaired vinylester layup dinghies, using both polyester resin and epoxy resin along with various glass 'cloths'. All have taken a gelcoat finish blended into the original without a problem. Also in one case the hull was designed to be flexible on a portion and it retained similar flex to the undamaged other side. Proof of the pudding in one case, was a few 30-35Kn races a few months after repair!, no problems at all.

    If you feather the repair in properly, you should not get a problem. I would doubt using vinylester would be any different. It is frequently used with a polyester gelcoat surface, which seems to bond fine.
     
  5. pescaloco
    Joined: Feb 2006
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    Location: so. california

    pescaloco Senior Member

    You know I was reading up on a bunch of different articles and came across those quotes
    Now that you mention it I think it was from an epoxy supplier

    Thanks for the feed back
     
  6. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 473, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    If from an epoxy supplier, you may have gotten much of it correct. Polyester doesn't stick well to epoxy. Vinylester sticks a little better, but give a strength choice, epoxy would be the best option.
     

  7. FishStretcher
    Joined: Oct 2011
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    Location: On the Water

    FishStretcher Junior Member

    Vinylester is more properly called epoxy vinyl ester. The stuff I buy - F010-TBN-28- has mechanical properties equal to or superior to run of the mill epoxies you typically see.

    I love the stuff and it is obviously much tougher and tougher to remove than polyester. This is an issue when grinding a vinyl patch section, as you will remove polyester quickly, and the vinylester will stay.
     

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