please advise on making a male mold?

Discussion in 'Fiberglass and Composite Boat Building' started by tugboat, Aug 10, 2013.

  1. groper
    Joined: Jun 2011
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    Location: australia

    groper Senior Member

    Nope, there is no compound curvature in that hull and it cannot be made like that if there is compound curvature in the design. Each panel has simple curvature only.
    I would strongly urge you to reconsider your need for compound curvature below the waterline as noone will ever see down there anyway. It will simplify your dream significantly...
     
  2. tugboat

    tugboat Previous Member

    I agree it would make it easier...however c-flex should work- I just ordered it..I got a refund on my HC core(thankfully) and ordered the c-flex. It will shape to just about any curvature with ease. I am not sure if
    Ill use the rib band method or just simple frames...thoughts?
     

    Attached Files:

  3. tugboat

    tugboat Previous Member

    SamSam- thanks! because of your input and after a lot of research-and talking to the inventors son William Seemann who runs the company;
    - I ordered enough c-flex to do my hull...thanks for the suggestion.. now I've got none of the worries of a cored hull...I can form my boat easily to the shape I want, and its affordable....
    I have started my mold stations pls watch my vid...

    https://www.youtube.com/watch?v=qq8o_fmQa7M

    cheers!
     
  4. groper
    Joined: Jun 2011
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    Location: australia

    groper Senior Member

    C-flex should suit your needs nicely - its just like a synthetic version of a WRC strip plank build now - i like it. Over here we have strip plank cored 1 off construction method, so we can order a foam or balsa core with light UD laminate both sides in 12" wide planks - called duracore. After completing the planking, a +-45deg laminate is overlayed to give strength in the other axis.

    Your going to have fun with that stern section, youll need to rip down the c-flex into very narrow strips. Id also reduce the forma/ station spacing there too.

    You seem like a can do kind of guy, if this is the case and your not afraid of breaking tradition, id strongly encourage you to infuse your hull laminate - and heres why;

    It will save you money - you will use heaps less resin.
    It will save you heaps of time
    It will save your back
    You wont have to breathe up styrene fumes for days on end

    So what you will need to do is, complete your hull in the c-flex then fair it a bit using resin/filler same as youd do in preperation for your main laminate. Then complete the first light layer of fibreglass by hand / wet layup to get the whole thing vacuum tight.

    Then this is where things change, instead of continuing with layer upon layer of laborious laminations, simply drape over ALL the layers of dry fibreglass without wetting them out in 1 shot - this will go very quickly - youd have them all on in 1 day. Vacuum bag the whole thing and seal the perimeter to the edge of the hull, and wetout the entire lot letting vacuum pressure do the work rather than your back with a paint roller.

    If you do the reading required, theres people online who can help you get it done with no sweat... i think its an ideal process for someone in your position, something to think about...
     
  5. tugboat

    tugboat Previous Member

    Groper awesome! This sound like a great idea and it will be thoroughly investigated.

    is this the same thing as in core infusion? If so Hankinsons book(sorta my bible) has a has chapter on vacuum bagging...if not please let me know who I could pm to find more info on this method. It has the benefits of doing it with a good bond- and fast too. If I'm understanding you...?

    the reason for the many stations molds at the stern is so the c-flex will not sag at all.- not that it should but in the c-flex manual it states frames to be 18" apart if over 25 ft. that's a lot of frames...
    so I was trying to stay within the parameters.


    if you do have any more info on it i.e. setup etc. Pls advise...

    btw- I watched a video of c-flex being applied, and talked to Bill JR. at c-flex and it seems it should have no trouble at all forming to the stern...
    if I have to use strips I will, but I don't see it being an issue- when they take it off the rolls it contorts and flex's like a slinky! check it out...

    https://www.youtube.com/watch?v=-TRhnBZNMu0&list=FLwsdyJEr84xAz2OoXkhPr6Q&index=2
    cheers!
     
  6. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    Well, it's good you have something to work with. I have a bit of a question, in your video looking at 2:55 and 5:15 it seems your 'chine' or transition from side to bottom is kind of a lumpy curve. Why is it like that? Why not have a smooth curve there? The rest of it looks pretty smooth, once you get around the transom corner and are going down the side.
     
  7. groper
    Joined: Jun 2011
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    Location: australia

    groper Senior Member

    Yes i noticed the same thing samsam...

    Tug,
    You wont have any problem forming the curve with the C-flex, its just that you may have to rip it into narrower strips. It will be fun regardless, it will be difficult to get it all sitting perfectly fair, youll no doubt do some filling and sanding later...

    Info on infusion can be found in my build thread here -> http://www.boatdesign.net/forums/bo...displacement-powercat-build-thread-38588.html

    And also another guy here -> http://www.boatdesign.net/forums/fiberglass-composite-boat-building/infusion-plan-43380.html

    And this one is pretty comprehensive also, theres alot in it so it will take some time to get through it all and find the parts pertinent to you -> http://www.fram.nl/

    And his building blog here -> http://framsblog.wordpress.com/

    Theres plenty more info out there too.

    Infusion saves alot of time and effort especially for thick laminates like you plan to use... Its also great for working alone.

    Wet laminating as shown in the video you linked to before, looks easy enough when you have a team of experienced guys all working together like clock work, one person mixiing resin, another cutting glass, another rolling it in etc etc... Its not so easy like that when your on your own and its alot of hard work and resin ends up everywhere -sweat will be pouring off you... Multiply that by the number of layers in your laminate and all the while stinking the place out with styrene fumes everywhere... its not nice.

    Infusion you can take your time setting everything up, and its light work, no fumes, clean workshop. Once everything is ready and has been checked, youll be mixing an entire 44gal drum of resin and infusing the hull in a couple of hours. The method youd likely use is the SCRIMP infusion method, whereby a flow media distributes the resin throughout the layup under the vacuum bag film. Youll need a vacuum pump, which can be had on ebay for around $200 last i checked...
     
  8. tugboat

    tugboat Previous Member


    SamSam - yea- that's just because the area of what is a radiused chine actually has been flattened out .it simulates a double chine... this was done to make a potential core material(I was looking at using core prior to the c-flex) easier to form using two compound curves rather than three- I have thought of rounding it off...but I wanted to keep a leading edge on either side of the radius in order to adjust my fit of the c-flex...hope that makes sense?...

    should I just round them off?
     

    Attached Files:

  9. tugboat

    tugboat Previous Member

    groper- thanks for all that info- ill read everything I can on it- I've been reading about it now for some hours on the net- some say it takes practice if an amateur, so it does intimidate me a little...what happens if you "eff" it up? can it be easily repaired?
    how much in setup costs? I.e. all the other materials?..i have been trying to cost it out...

    how do I determine how much resin will actually be needed? I am planning on some fairing with filler putty- that's for sure but hoping I can keep it to a minimal.
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    would that work?
     

    Attached Files:

  10. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    No. You throw he whole mess away, all the resin that has gone off, all the voids, all that expensive FG material - its all &^*(# ed

    An amateur doing vacuum bagging on 20 footer is a big ask.

    make sure you do a lot of small jobs first - do the tender, superstructure components - internal panels etc
     
  11. groper
    Joined: Jun 2011
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    groper Senior Member

    Dont be so quick on that RW - how much infusion have you done? Usually the stuff ups are localised, and only require a patch repair. Every link i gave eariler, are people who have done it successfully, with no prior experience - so its very doable for a first timer. The thing with infusion is, you dont have to mix any resin, until you know everything is right. If something is wrong, you have to have the discipline to go back and fix it, and not just mix the resin and say "she`ll be right" - this is where you make the monumental stuff up. If everything is right, and youve double checked everything, it generally goes like clockwork.

    Infusion is VERY intimidating... at first anyway. The idea of stuffing up thousands of dollars worth of materials is very daunting for a first timer. What i did, is to start on very small parts. With this you gain confidence and learn alot about things you just cant cant learn from books or online etc. You need to see how the resin moves and get a bit of a feel for all the little problems that can arise. Then once your confidence grows, you will know when you are ready to do the full hull- trust me, you will just know.

    Once you know how it all works, youll also realize that the bigger the job is, the better suited to infusion it is and the more efficient it becomes. These days, i wish i had a giant mold so i could infuse a 50 foot sandwich cat all by myself in 1 shot - but ill save that for the next build knowing what ive learned to date... ie. build a big mold first...

    That vacuum pump is basically the same as mine, its gtg for this...

    For your laminate, you will save money if you infuse it because the reduced resin consumption will more than offset the cost of the consumables - the vacuum bag film, perforated film, flow media, sealant tape, resin feed lines etc etc

    I can calculate all your resin consumption down to the last drop via a spreadsheet - all i need is the layup schedule and flow media type. Dont worry about this, i will help you later should you wish to proceed...

    In the mean time, you need to do lots more reading, and decide if you wish to go this way - i think your the kind of guy whom it will suit well.
     
  12. rwatson
    Joined: Aug 2007
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    rwatson Senior Member


    Lets see, I thought I said "you can stuff up lots of material" and "start off small at first" just like you suggest here

    Oh look - I did say that !!!


    Oh, and there "is lots to learn that you cant get from books and such" !!

    oh and "get a bit of a feel for all the little problems that can arise. "


    Problems ? What problems ? Its all so easy for a first time user !!

    Remember - no one posts the big infusion stuff ups on YouTube !!
     
  13. groper
    Joined: Jun 2011
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    groper Senior Member

    No need to retort RW, if you understand what i said and why i said it...

    Theres no need for Tug to infuse his whole hull straight up - he can practice on smaller parts before going for it, such as bulkheads or deck panels or pilot house panels, all that sort of stuff... When he feels confident, he can go for it.

    I dont need youtube to see infusion stuff either, i have it going on in my workshop every other weekend... monumental stuff ups are pretty hard to achieve, unless your a total goose who neglected everything they should already know before mixing any resin. I have not binned an entire infusion job yet, not once. Sure ive had problems, but these are usually localized and only require a patch repair, nothing major, and these were problems i experienced early on whilst i was still learning.

    Even if Tug ends up with a few dry spots in his hull, the time to fix them is nothing compared to the time and money saved from infusing it.

    Its quite rare that infusions end up as total write offs, id love to know where that rumor started as i see it passed around the web often without any real basis to it... It is common to have localized or cosmetic problems tho, but there are strategies available to control these, a prudent operator would familiarize themselves with them before jumping in...
     
  14. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    Myself, I would round them off. But what it looks like is the radius has been modified by taking material away and to round them off you shouldn't just round off the existing corners but add to the flattened areas. Since the forms are just to hold the c-flex in position until resin coated, it shouldn't be hard to do and it doesn't have to look good. The extra bits of crescent moon shaped pieces could be cut out of scraps and hot glued/regular glued/nailed with brads etc.
     

  15. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    I have seen infusions with whitish areas-resin starved is what it looks like but maybe it's entrapped air- and it's treated as a minor problem, almost cosmetic. In a hand layup that would be a bad problem structuraly and water integrity wise, and you can't easily fix that. Is that easily fixable with infusion?
     
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