Filling in the cracks in the foam Core

Discussion in 'Fiberglass and Composite Boat Building' started by packsail, May 31, 2012.

  1. packsail
    Joined: Feb 2012
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    packsail Junior Member

    I'm using divinycell foam core for my catamaran. We're currently laying the divinycell on the mold and since it is grid cut with scrim backing we are getting large cracks in areas of curvature. Can someone give me some ideas on how to fill these cracks in to prevent racetracking and printthrough during the infusion process?
     
  2. packsail
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    packsail Junior Member

    Attaching a picture

    Here's a pic of my one off male mold as we are laying the foam core.
     

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  3. Herman
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    Herman Senior Member

    You can add some rovings into the larger cracks. There are even special braids for that. (gusset filler). However, if you do not want the large cracks, it would be better to heat shape the foam, or use micro-scrim (15x15mm) instead of normal scrim (30x30mm).

    Anyhow, at this point you will have to live with it. Adapt the infusion strategy so that the racetracking does not spoil your part. In other words, make sure the resin front goes parallel to the largest race tracks. This will mess up the resin front just a bit, but nothing really harmful.

    On printthrough: This does not seem to be a real issue on male moulds, as you will need to rework the surface anyhow.
     
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  4. tunnels

    tunnels Previous Member

    what ????

    simply put you should not be asking such a question at this stage of the construction . you should have had all these kinds if things well and truly sorted before you ever laid the first sheet of foam !!!! who is in charge of this job ?? you need to get you act together !!!:eek:.
     
  5. TeddyDiver
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    TeddyDiver Gollywobbler

    Tunnels.. cranky today?
     
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  6. rawleyjerel@yah
    Joined: Apr 2012
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    rawleyjerel@yah Junior Member

    when divinicell is produced sometimes it has bubbles that surface these bubbles are filled with putty at the factory it is a low density porous putty id contact the manufacturer for the name of that putty or a easier solution is to get some cans of spray foam that are the same poundage as the core spray it directly on the cracks and sand them flush. ive done this in the past and it had no bad effect
     
  7. tunnels

    tunnels Previous Member

    wow

    Where do you work ? what do you make ? i want to know because if thats the way you do things i want to know to keep away from you !! spray foam !! why not Just use toilet paper its doing the same thing and about as useful !! :confused:
    I worked on some pretty bad things over the years doing repairs and funny most of the products were from the USA !!

    WOW !!!
    Have i had a bad day ? not yet maybe after i hear the reply to this !!
     
  8. rawleyjerel@yah
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    rawleyjerel@yah Junior Member

    <insult directed towards other member removed>. seems the fiberglass and infusion were invented in the united states i think that you should shut your mouth. what would you do <insult directed towards other member removed> the spay foam fills the entire void leaving none and as long as its the same density as the core it will exept resin the same as the core <insult directed towards other member removed>. if you got nothing good to say then say nothing ya the united states were the process was invented not copied like in your country. just like everything else <insult directed towards other member removed> like to ***** about the united states and then mimick us thats pretty pitiful if you ask me and oh ya and the internet your on right now was also invented by the united states.
     
  9. Boat Design Net Moderator
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    Boat Design Net Moderator Moderator

    Everyone, let's please keep the discussions here polite and avoid the insults. Thank you.
     
  10. tunnels

    tunnels Previous Member

    sorry and i rest my case !!:)
     
  11. sabahcat
    Joined: Dec 2008
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    sabahcat Senior Member

    What we've used in Australia at that stage is to use a slurry of light low density filler and epoxy.
    Fills the voids with something stronger than the foam and fills the surface of the foam.
    Light sand to knock the highs off and scuff surface.
    Probably use less resin when bagging due to surface being filled

    Of course you could just do what "some" production builders do which is nothing causing crimping of glass and voids:eek:
     
  12. idkfa
    Joined: Sep 2005
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    idkfa Senior Member

    Why, oh why do the US still use the Imperial Units? It is really perplexing why you guys have not joined the rest of world, NASA has!

    So, yes many great things have been invented in the US, and yes probably "America" (not the continent) is still the greatest country on the earth and most people would like to go live there.

    But can you imagine how bone-headed and annoying it seems to rest of us?

    IMHO idkfa.


    btw, spray foam is friable and may have water ingress problems.
     
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  13. Herman
    Joined: Oct 2004
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    Herman Senior Member

    When things go complicated, even imperialists (pun intended) turn to metric. How about a coating thickness of 20 mil... (20/1000 of an inch) :)

    As for the topic starter: I presume the top laminate is on now, and the boat infused. Show some pictures!
     
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