Fishing boat cabin rebuild - reshaped

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

  1. dzausta
    Joined: Feb 2013
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    Location: Australia

    dzausta Junior Member



    That was 1oz csm? cloth mentioned would be my roving ye?

    what material should I use for the cloth(roving or cloth?)? and if you mean another layer of roving should I lay a light csm for better bond between the succeeding roving layers?
     
  2. tunnels

    tunnels Previous Member

    By adjusting Catalyst ratios you can creat a window of a set time to work with your resin . so you need to fix in your mind how much of the work you can accomplish in that given amount of time , as you get each part done you will learn and get quicker as you go along !!
    just sucking a core down is as simple as it gets . if i didnt think you could do it i would have talked you into using COREMATTinstead !! but the foam core is a better way to go .
    Most hire places could possibly have a vac pump to hire rather than buying one for just one job .
    No a vac cleaner wont work because it needs a continuous flow of air to keep the motor cool and not melting its self into a smelly cooked blob !!
    Theres been a few that have tried and every one has failed !! :eek:
     
  3. dzausta
    Joined: Feb 2013
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    Location: Australia

    dzausta Junior Member

    Great stuff ! I think i just might do that, was concerned with getting a cheaper pump and it failing on me half way through. I'll have a look around and see what they have at the rental shops.
    Would you know if the pump bellow would do the job, it does 6 cfm, I think pumps like this would be readily available at the rentals.(I might even have one)

    http://www.ebay.com.au/itm/6-CFM-Si...ools&hash=item4d04a487a7&_uhb=1#ht_1686wt_986

    ps. have you read my previous message
     
  4. tunnels

    tunnels Previous Member

    Because you are only sucking the core against a wet layer of glass theres not to much suction required !! only if you have a tight curve to pull the core panel against ,so 6 mm foam core first !!,then later 5 mm core matt to butt against the foam will be easyer to work with . Its really interesting doing vac bagging and you will have a smile a mile wide when the first panel goes down and is sucked into the wet glass!! its increadable to watch it happening and how the resin works its way to the top and covers almost all of the foam and seals it 100% !! :)
    Even after 20 years the thrill is still there everytime !!:p
     
  5. dzausta
    Joined: Feb 2013
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    Location: Australia

    dzausta Junior Member

    Just a thought, when i lay 2 foam panels next to each other should i cut the edges under an angle an lay them on top of each other like a scarph joint or use a butt joint?

    Also what pressure should I run the pressure pump at? I saw how bubbles expand under vacuum and was wondering what effect would this make on the air inside the foam?
     
  6. tunnels

    tunnels Previous Member

    have tried many differant methods of joining sheets butt to gether seems to work ok no problems . use the longest sheet at the curved end and have your joins on flatter areas so the wont peek together . How much vac is required !! just enough to pull the sheets into the wet glass and hold it flat against , and if theres a surface with a bow then make sure it pulling it down 100% all over . just introduce a little air into the suction line at a join to maintain the pressure you need and you could be amazed it might not be much !! just need to be maintained and held steady for a couple of hours . till the resin has gelled and cured and gone hard so when the pressure is released it wont spring off around the edges where the curve is .
    i love working with vac its really interesting !!:)
    Effect of vac on the foam ! non even if you could obtain max vac suck still wont effect the foam in any way !!
     
  7. dzausta
    Joined: Feb 2013
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    Location: Australia

    dzausta Junior Member

    I'm excited about the process as this is the way I wanted to go about it initially, but thought that it would be out of my scope and cost a lot more. I've been doing my research for past few days and it doesn't look so scary as it did initially. This weekend I will be making my mold, ill post photos, than I wont get a chance to do any work for a while as im going to Indonesia for a holiday the following week. So close but so far! One more thing, I read one of your posts where you explained possible causes of aligatoring of the gel coat, it was mentioned that some of the possible causes are the accumulation of the styrene (cant remember if it was styrene or something else) and a fan could be used to help some of it evaporate? How long after I apply gel coat would it be safe to start glassing? I know it all depends on the given settings of the environment but lets set a baseline.
     
  8. tunnels

    tunnels Previous Member

    Gel coat !! basicly its just like resin but has pigment in it to give colour and lot other things as well for weather and uv protection etc .
    Its consistancy is reasonably thick and is best sprayed if possible but can be brushed for the first coat and a mohair roller for the second coat ,i find is best , Also add a little resin to the mix for the second coat makes it easyer and quicker to apply and a smoother finish to glass over !!
    Talk to your supplyer and ask what catalyst to use and what ratio !! Is usually 1.5% catalyst for the first coat , then 2% catalyst for the second coat .
    The first coat should be able to be second coated over at about 3 to 4 hours after it was applyed should feel a little slightly stick to the touch ! but thats a good thing as its for secondry bonding to each other

    ALLIGATORS ARE CAUSED BY THIN UNCURED GEL !! usually
    THE STYRENE THING IS MAINLY IN HOLLOWS AND IF THERE IS NO MOVEMENT OF AIR TO BLOW IT AWAY . Getting the right amount on is really important to get thickness . so if you brushing then think thickness !!:idea:

    As with all things do a small sample and chech your gel time !! and remember the egg timer to set when you mix the cataylst and start !!
     
  9. dzausta
    Joined: Feb 2013
    Posts: 50
    Likes: 1, Points: 0, Legacy Rep: 14
    Location: Australia

    dzausta Junior Member

    yep I'll have a thickness guage handy and I'll get someone to spray it for me, should I still add a little resin to the second coat if spraying?

    How long can I start glassing over the final layer of GC ? Is it still at 3-4 hours?
     

  10. tunnels

    tunnels Previous Member

    Ok if you have some one to spray it for you then the two of you work together one person catalyses the gelcoat and mixes and the other person sprays !!
    Second coat just roll it !!! its cleaner quicker and far less mess !!
    Gel coat Quantity per m2 is .6 kg or a little more so do a sketch of the deck and the areas and then you know if the right amount of product is going on each area !!
    Remember gel coat is not paint so it need thickness for whoever is spraying !!
    pressure pot is the best to use and a plastic container that fits inside the pot . just mix and place the plastic container inside and close the lid !! Remember the gel time !!it starts as soon as the catalyst is poured into the gelcoat and mixed .

    And yes use your thickness gauge !!
     
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