Microvoids/laminate questions

Discussion in 'Fiberglass and Composite Boat Building' started by fallguy, Aug 23, 2019.

  1. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    3F5D8B1A-B9B2-4501-B246-A1B88F52733F.jpeg So, if you have microvoids in wet bagging; does that guarantee you are a bit dry?

    Most of my testing showed my laminates were 35% resin to total (glass and resin) or 53% resin to glass.

    But I do have a bit of a concern my layup is drier than it could be.

    Doing some minor repairs; the glass does indeed seem a bit drier than I'd like.

    We are at a stage where post curing and fairing are next. Any concern about post curing micro voids?

    If I am nervous about being on the dry side; would it help at all to neat cost this all epoxy boat with epoxy for a harder shell? What about a light woven glass hand laid overlap?

    The boat has been hit a few times during the build and it does seem to delam a bit easier on the vac panels than on the hand laid stuff which would be 1:1 resin to glass.

    Most all the boat will get some fairing compounds.

    Pic is star hull.
     
  2. Tungsten
    Joined: Nov 2011
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    Location: Canada

    Tungsten Senior Member

    Take a piece of left over cut off from the hull that has these voids and do a post cure on it. Take macro photos before and after. See what happens.
     
  3. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    I did this today and there were no problems.

    I ran three different samples in the oven for one hour instead of the required two and they came out great. I did smell the odor of curing epoxy a bit. I figured the temperature exposure of one hour is really not much different than that of two hours. And the oven is pretty big for 3 small samples (lots of propane).

    Interesting to note, we did some crude impact testing on our panels as well. The vac bagged panels with micro voids and they outperformed hand laminated panels. I would say they did better by a factor of 3. The impacts were the same, but the hand laminated panels seemed to really break more than the vac bagged panels. I was completely surprised by this. During my time on the boat, I worked on the top deck some and the panels on top were hand laminated and seemed more durable, but it was all just my errant guess.

    My oven is forced air and it is getting pretty dry. I don't know if this is a problem, but during the post cure, I plan to send a little bit of water into the oven to try and stay above 1% RH. If anyone reading this thinks the dry oven is really bad, let me know. I can't think of a reason why it will be a big problem.
     
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