Fishing boat cabin rebuild - reshaped

Discussion in 'Fiberglass and Composite Boat Building' started by dzausta, Feb 27, 2013.

  1. dzausta
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    dzausta Junior Member

    I have to be mindful of the weight too as I am slightly moving boats CG. I was thinking of doing ribs using PVC foam. could that work ?
     
  2. dzausta
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    dzausta Junior Member

    Do I have to make the cabin layup the same as that of the hull or can i make it stiffer?
     
  3. Mr Efficiency
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    Mr Efficiency Senior Member

    You could use cheap polyurethane foam as formers for ribs, the glass being the stiffener, not the foam, which would just create the shape. If you are crossing bars, and there is the possibility of taking solid water over the front, you do need a strong structure, but 3mm should be adequate imo. And yes, the less weight the better for preserving stability.
     
  4. dzausta
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    dzausta Junior Member

    great, what would you say whats the best way to achieve those 3mm ? CSM only? I'm thinking of using WR for extra strenght is that a good idea ?
     
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    Does the clinker topsides have woven reinforcement ? I doubt it. Not necessary unless you are taking on bar crossings, and then it is just a bit of insurance and not making it proof to being busted by waves. It is hard to use woven roving on double curvature.
     
  6. dzausta
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    dzausta Junior Member

    If I was to go for 3mm layup what mat weight would you recommend I work with and how many layers?
     
  7. Mr Efficiency
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    Mr Efficiency Senior Member

    2 or 3 layers of 2oz mat should do the job. Guessing 2 layers might be a touch under 3mm thickness. A 3mm laminate would weigh (roughly) 5kg per square metre.
     
  8. dzausta
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    dzausta Junior Member

    1oz would be something like 255g equivalent in aust right?
    Thanks for the advice, glass suppliers were understaffed and didnt get my order ready in time, will have to do it next we. Didn't get your message in time so i ordered 1oz cloth, should be ok just double up on it.

    ok so im laying glass in 2 steps, skin while its on the plug and the rest when its off the plug . Skin has been put down already wich consists of 4 layers of 200 g cloth than im thinking of putting down 2 layers of 1oz CSM than 570g roving so that the cloth and the roving can take most of the forces.

    Question, how is rowing laid normally? Is there another layer or csm laid on top of the roving or is it ok to leave rowing as last layer? Thanks
     
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  9. dzausta
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    dzausta Junior Member

    ok now im thinking laying down 3 layers or 1oz cloth (should have bought 2oz instead) on top of previously laid 4 layers of 1 oz cloth than a layer 18oz roving. Is this sufficient and should i lay another layer of csm n top of the roving or leaving roving last is ok? Any thoughts on this layup?
     
  10. tunnels

    tunnels Previous Member

    Enthusiasum !!

    wow so you are going to lay straight onto the foam and wood etc ?? how you going to get it all apart and get all the stuff out from inside ??
    so you just have the semi finished shell of your cabin ??
    What resin you using to make all this ? polyester i hope !! ir even vinylester is pretty cool !
    Id be inclined to make a nice job of what you got and make that the mould you have up to the point of sanding filling and fareing etc and gel coating etc and waxing then that will be the finish you will have on the inside of you cabin when its released off the mould .
    If you do the glass work on the outside over the waxed surface thn gelcoat and a layer of chopped strand matt then you good glass and a 9 mm HD perfirated sheet foam core vac bagged onto the glass !!,
    then Filled, rounded, and shaped etc etc then glass the outside and finish off again with a chopped strand matt as a final layer to sand and fill etc then its the fareing etc etc to get the outside 100% and paint it with a really good 2 pot paint .
    Lots shaping and sanding etc but the chopped strand is basicly sacrificial So you dont damage the good glass cloth underneith . Thats where your strength is so dont sand through it anywhere what ever you do !!.
    :D
     
  11. dzausta
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    dzausta Junior Member

    ok what i probably didn't explain myself properly so i took some more photos to explain where im at.

    [​IMG]

    [​IMG]

    [​IMG]

    So what i did there is (as per your post on another thread tunnels) I sprayed the hell out of the plug with PVA than laid 4 layers of 1 oz cloth on top of the plug. Than I will separate the skin from the plug and lay the rest of the leminate on the inside of the skin. Im working with vinyl ester resin for this project.
     
  12. dzausta
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    dzausta Junior Member

    also there wont be any foam used for this cabin, I only used foam to get the shape I wanted.
     
  13. tunnels

    tunnels Previous Member

    Keep at it !!!

    The foam i suggest is a 9 mm high density sheet foam for the cabin to make it stiff so you wont get sides moving and the flatish area in front of the screen if you just happen to ship a green wave sometime it wont cave in !
    The lay up is really light weight so the foam is to give it stiffness without adding lots of glass . The wet chopped strand i suggest to use to stick the core with also is adding lots to the stiffness and strength where its placed in the laminate stack !! The good gass you have is really light weight so needs something to give it all the support and stiffness possible just make a small test strip one with just solid glass and one with the 9mm core and you will see what im getting at . you can also measure the weight of each panel and see theres not a lot of differance !!,just the stiffness is far greater and 9mm core is really easy to work with !! ;)
     
  14. dzausta
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    dzausta Junior Member

    now I have even more questions :) please be patient with me and bear in mind that im green but very keen.

    Ok i had a look around for the foam today, the foam is very rigid right? or is it a core mat/core fabric thats rolled out? if yes rigid that means I could only lay it on my flat parts right?
    I think I found what you were talking about.
    http://www.lantor.nl/index.php/id_structuur/10598/coremat.html

    Since I already bought 1oz chop strand mat can i still use it but just double up on it (2 layers would make 450gsm )?

    If Yes to questions above my layup would look like this

    4layers of 1oz cloth
    2layers of 1ozCSM
    9mm foam core/core mat
    2layers of CSM
    18oz woven roving

    is that right?
     

  15. dzausta
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    dzausta Junior Member

    i could only source 5mm coremat, would that be sufficient?
     
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