New Design Temporary Female Mold Build Help...

Discussion in 'Fiberglass and Composite Boat Building' started by bjdbowman, Feb 12, 2018.

  1. ondarvr
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    ondarvr Senior Member

    I didn't go back and read it again, but people that want simple tooling on cats use symmetrical hulls, so no reversing anything. You make one bow mold and it works for all four pointy ends, then one hull mold section and make as many as you need to for the length of boat you desire. These molds will need to be a little more durable, but you can put a better finish on them and have less work to do later.

    Wax paper and plastic can be used as a release film, but doing it in a female mold is tough, and the surface on some shapes is poor at best.

    There are sprayable waxes, I used to use one that you heated up, when sprayed it would cool and become a little firmer.

    Hand waxing melamine coated plywood is about the easiest thing you will do in the entire project.

    There are spray, roll or brush on sealers that will give you a much better finish on plywood with no sanding, but they do need waxing.
     
    rxcomposite likes this.
  2. Rumars
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    Rumars Senior Member

    Well if that's your goal then just go buy an old cheap fiberglass boat. Some places they are even giving them away for free. Even if you have to repower or redo some of the interior you will be ahead of the game in terms of time and money.
    If you try to build you will only waste money and put yourself in danger.
     
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  3. fallguy
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    fallguy Senior Member

    F8AB6060-9466-41AE-AD8C-338ADCE5D80A.jpeg 57E488B0-66BD-402D-91C8-89B9EEF253A2.jpeg 43F3CC5F-84F2-463D-8C36-9CDA67294657.jpeg C4D682BC-AD90-4EC9-9E49-52665DCA1E94.jpeg 53A4C314-B574-4CA4-842C-F6FB081A269C.jpeg Here is a female jig in various stages and a vac table. The hull is lifted with a gantry as there are no pick points or places for humans and the size at 32’ is too heavy for safe man lift. This space is 24’ wide by 36’ long for 32’ cat. Only one hull at a time can be built with this space and method. The first hull is outside under cover. In order to facilitate this build; it takes several people to vac bag a large panel and two people to move them into the jig. You could use other methods, but the cost of one of the four main hull panels (8 needed) is about $600 for core and about $400 for glass and epoxy and consumables and &400 labor.

    You would be better off building in plywood if you want a cheaper boat that is easy to build. With plywood; you can build the boat and handglass it. The method I am using is 3000 man hours.

    Start with budgeting time, money, and space.
     
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  4. ondarvr
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    ondarvr Senior Member

    I tend to agree, if time, effort and money are a concern, buying a used boat is cheaper, faster, and most likely safer.
     
    fallguy likes this.
  5. rob denney
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    rob denney Senior Member

    Wax paper over the mould will work well as a release, although some Australian wax paper doesn't work so try it first. Any tears or missed overlaps and you have a stick up. Brown packaging tape also works, but after one application, tends to fall off. We use thin plastic (about the same thickness as Cling Film, but without the clininess) drop sheet material as it comes in 6m x 4m sheets and has a bit of give.

    Gel coating any of these is a waste of time and material. The gel coat will need sanding and polishing to look presentable and all the joins will require gel repairs. Put a layer of peel ply wherever you want to paint or secondary bond, it is much easier than sanding. Use house paint.

    What you are planning is easier, rougher, heavier, dearer and maybe quicker than conventional bucket and brush building, but will be slower and use more materials than Intelligent Infusion INTELLIGENT INFUSION – Harryproa http://harryproa.com/?p=1845 which is a development of the build method of the hull in the video above. Making 3 moulds then reversing them and hand laminating 6 panels then joining them and filling and fairing the result is crazy when you could build a mould and infuse 2 x half the hull and deck, then simply glue in all the exact fitting bulkeads and glue the 2 halves together, with all glue joins being self aligning. No edge treatment, no grinding or cutting cured laminates and no wet laminating. Half a hull for a 36' cat will be liftable by 4 people. or solo if you have reasonable roof beams or can make a scaffold.

    Maybe build a small piece of your boat (or just list the stages and give each a time, mess, waste, toxicity and hard work rating), then consider which is the best way to proceed.

    Bolting sections of hulls together is a good idea, we use it for removable bows. For major sections of hulls, especially those with shroud, forestay and traveller loads, the reinforcing around the bolt holes should be massive and far reaching. Doorways, etc in the bulkheads should be well above the waterline as you will be lucky to make it reliably watertight. Multiple bolts will help keep it aligned. The work involved in all this will make you wish you hadn't.
     
  6. bjdbowman
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    bjdbowman Junior Member


    I have experimented with wax paper, attaching over plywood does not work very well. The wax paper wrinkles with the use of all the glues that I tried... the finish ends up looking like orange peel.

    I like the idea of a paint on sealer and a paint on wax. What brands do you suggest? Any links? Have you any photos of using these products?

    Thanks for the help... Again I want to use a stitch and glue type design in a female mold using exterior frames and 1/4" and 1/8" luan plywood. I also have some bendable plywood (will bend only in one direction) left over from a project that I will also incorporate into the design of the mold.

    My issue is preparation of the plywood as simply and cheap with as little labor as possible.

    Thanks again...
     
  7. bjdbowman
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    bjdbowman Junior Member

    Wow, all great information.. thanks... I was thinking of ply-peel to the female mold with the finish side inward, gluing the back on to the mold... I don't know if this is expensive or even possible... as far as seams and sizes of materials.

    What about these plastic sheets? Do you have an example supplier or a link to what you are referring to? I use house wrap (tyvek) and the plastic tape... I could glue this down over the ply and then wax it... but I don't know how many layers of wax of if there would be a simply spray on one or two application method and the spray on a layer or two of PVA. What do you think?

    As for the gel-coat... I just wanted uv protection and a better base to paint over. If not needed then I fine with saving the money. What do you mean about using House Paint?

    As far as the segmented hull, I agree that it is more work and heavy, but this is the only way that I will be able to create what I am looking to build on my own. I can move the small parts around on a wheeled gantry and build the boat in two halves completed for shipping to the launch site for final assembly.

    Thanks again for your input and directions.
     
  8. bjdbowman
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    bjdbowman Junior Member

    Yes, I would agree with you, but I don't want a typical boat... my design is unique for what I want to do, thus I cannot find anything close to my design on the market nor will I ever. Thus I need to build it myself. Not only that, but this way, I can incorporate the technology that I want into the boat from the initial design and not have to Jerry-rig an after-the-fact abomination onto a production hull.

    Thanks for the reply... I am looking at this as a project that I want to do... not that I have to do... a bucket list issue.

    Thanks again.
     
  9. bjdbowman
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    bjdbowman Junior Member

    Yes, I would agree with you, but I don't want a typical boat... my design is unique for what I want to do, thus I cannot find anything close to my design on the market nor will I ever. Thus I need to build it myself. Not only that, but this way, I can incorporate the technology that I want into the boat from the initial design and not have to Jerry-rig an after-the-fact abomination onto a production hull.

    Thanks for the reply... I am looking at this as a project that I want to do... not that I have to do... a bucket list issue.
     
  10. bjdbowman
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    bjdbowman Junior Member

    Yes, this looks like a great option... What model/designer is it that you are building?

    Thanks for the input... this may end up being a similar method that I will need to use.
     
  11. bjdbowman
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    bjdbowman Junior Member

    Yes... you are correct, but I think the segmented hull is what will work for me, building with a one man team. I can move small parts around easy and working time of the epoxy is also an issue. I like the idea of small manageable parts that can be tab/slotted together and bolted... all with a small crane and one man.
    Thanks for the reply.
     
  12. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Wax paper as as isolation membrane doesn't work with thermoset plastics. The wax tends to melt and the goo sticks to the remaining paper. It's also lousy paper and tends to wrinkle (as previously mentioned). There are several plastics that do work well in this regard, such as packaging tape, painter's drop cloth plastic, etc. Mylar, polypropylene, polystyrene, polyester and similar for good results.
     
  13. rob denney
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    rob denney Senior Member

    Pinters drop sheets from the local hardware.

    I think that waxing a mould that will be painted is almost as absurd as hand laying fibreglass instead of infusing it.

    If you aren't worried about the looks, then the paint is only to prevent UV damage, so cheap is fine. If you are worried about looks, make a proper mould and save yourself hours of turning expensive product into dust.

    It's not. A hand laid segment of 1/3rd of the hull, plus flanges will be heavier than an infused half hull and decks.
    You are at least quadrupling the hours to build the hulls, using far more resin and glass than you need to and shortening your life (stress and exposure to lethal chemicals) doing it the way you propose vs infusion. Wet laminating and vac bagging, done properly, gives a better job, but wastes about half the resin and the stress levels are even higher, as is the chance of a stuff up and rejection. Read fallguy's thread to find out some of the ways you can screw up vac bagging.

    Thanks again for your input and directions.[/QUOTE]
    My pleasure. Think about them while you are sweating your bollocks off wet laminating a small part of your hull knowing that, no matter how careful you are, you will have a substandard job compared to infusion.

    Par,
    Many plastics, including mylar, brown tape, painters drop sheet (particulalry poor without peel ply) do not stand up to (Australian) infusion epoxy resins, nor to many standard resins. If you get more than one shot out of them, you are doing well. Not a problem if you are only doing a single shot.
     
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  14. bjdbowman
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    bjdbowman Junior Member

    Rob,
    I do see your point, however for me, I think that creating smaller parts and then "mass producing" the same part multiple times will add efficiency and less stress. I don't want to have to be stressed about laying up large parts or hulls by my self. I have a concept that will allow me to quickly and safely create parts that are strong and stress free for me and if I have a bad experience on a small part, I can learn how to improve on the next one.

    The idea is to be able to produce the parts with a small footprint configurable strong-back or jig, a fiber-glassing trolley and a simple 4'x8' flat table, all within the confines of a typical double garage. Here in Florida we get afternoon rain every day during the summer and thus the desire to build within an air conditioned space out of the elements.
    I would assemble the parts within a covered shed, but I want to be able to control the temperature and humidity when fiber-glassing in a tyvek suit, face shield and a clean breathing apparatus. I also want to control the fumes by installing a robust exhaust fan. Creating parts and fiber-glassing outdoors, and then tying to control these elements would be impossible.

    So these are my "givens" for the glassing area. If I do end up using the infusing process (hard for me to see this process on my design), it too would have to be within the same small build format, and I would have to be able to do everything myself with out the stress of time and cleanup after the end of a long day. If I could just work 4 hours a day, this would be perfect for me. I am not going to stress out and have to work 18 hour days just to get a single part created... or having to worry about the epoxy going off before I had the chance to complete the work.

    Small parts in a small space is really the only way that that I can see that this project will happen. I will try some experiments to ensure that I have a system that I am comfortable with before I set up the space for actually creating the parts. I want to start to collect the materials now and I want to ensure that I am moving in the correct direction. I have done fiberglass before and I am confident that I could do the work required, but only if I keep the parts small enough.

    Surely, I am not the first to have these same worries, restrictions, expectations? Some one must have built a composite boat in segments here in these communities... I know that production boats are made from multiple molded parts and then assembled... why not take this to the next level and design the boat and the process for a one man production with a limited space?

    I will look more into the infusing and foam core process... I need to find some actual local guys that can teach me the epoxy preparation process and the equipment clean up process for reusing the equipment... as I said, I want to build many small parts and mass-production is the key for me. Having to build the same parts over and over would require a method that would benefit from an easy to replicate process for each part. The infusing process looks easy enough, but complex enough to bugger it up, and there is the equipment cost as well.

    Thanks everyone for the information...
     

  15. Rumars
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    Rumars Senior Member

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