Kevlar canoe build

Discussion in 'Fiberglass and Composite Boat Building' started by Sneddy71, Oct 13, 2020.

  1. Sneddy71
    Joined: Oct 2020
    Posts: 2
    Likes: 2, Points: 3
    Location: Canada

    Sneddy71 New Member

    Hello,

    First, I hope everyone is well, these are crazy times.

    I have been in the process of designing and building a kevlar canoe. I’m doing as a hobby but also because I’ve wanted a stock racing canoe but don’t want to spend in excess of $4k to get one.

    I have had a copy of James Moran’s book for a few years and decided to give it a go. I made a few adjustments to the solo canoe plans in the book and got to work. I’ll try and post pictures. Currently I am almost done the male plug mould, and am somewhat nervous about the next steps.

    As my mould is almost all drywall compound with some small areas of pink insulation board exposed, I am wondering if I should paint it next to seal it a bit. The book goes into using a release agent wax but I’m wondering if there is a better more modern product to use. Also I’m considering making a fibreglass canoe as a first run to learn but also maybe use as a female mould if it goes badly. My hope is to make 5-6 canoes, so a female mould could work better, but I’m not sure what kind of product I’ll get if I lay up over a make plug and either roll the epoxy or squeegee it on. My plan is to use a kevlar inner layer and a inegra outer layer, or perhaps a basalt/inegra outer.

    Anyway, I’m hoping to get some advice if possible. Thanks in advance.

    p.s. picture didn’t load in correct order.
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    kenfyoozed and hoytedow like this.
  2. Sneddy71
    Joined: Oct 2020
    Posts: 2
    Likes: 2, Points: 3
    Location: Canada

    Sneddy71 New Member

    So I’ve decided to go directly to marking a female mould, I’ve added a stiffener flange around the what will be the top of the mould. Sandable primer next, many coats then a sanding with 400, 800, 1500 grit, followed by a top coat and sanded again. 8-10 coats of wax, sprayed gel coat and fibreglass after that. The mould will be made in two pieces to facilitate temoving the mould, as well it will store better when I’m not using it.
     
  3. ondarvr
    Joined: Dec 2005
    Posts: 2,337
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    Location: Monroe WA

    ondarvr Senior Member

    Don't sand the primer to more than 180 grit, anything more is a waste of time and money. Any top coat worthy of using will easily hide 180.

    I normally recommend 120, sometimes even 80 grit.
     
  4. ahender
    Joined: Jan 2009
    Posts: 81
    Likes: 2, Points: 8, Legacy Rep: 10
    Location: Athens, GA USA

    ahender Junior Member

    I also have the book you are using.

    I have built two canoe molds. The first was a 17' male mold from my own design. I never completed the female mold. Moved and had to terminate the project. The second is a 12' female mold (whitewater boat). At the time I started this project I was doing a lot of whitewater paddling. Not so much anymore. With the whitewater boat, I went from using a badly damaged canoe a friend had, made a female mold with it using primarily dry wall mud to shape what I wanted, pulled a male mold from it, reshaped the male mold, then pulled a female mold off of it. I have tons of experience in what not to do. PM me if you have questions.

    Alan
     
  5. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    Nice work. Looks fairly wide for a racing canoe.

    What design is it?

    Dumb guy here, why not carbon?

    What is the expected finished weight and length?

    Where in Canada?

    Would you sell the mould ever?
     
  6. fallguy
    Joined: Dec 2016
    Posts: 3,344
    Likes: 440, Points: 93, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    I would use a wax and a spray both.

    only thing I have ever used is pva and it worked! I had one sticky spot where the spray must've missed on top, but the wax helped

    Here is a really interesting how to on partall. Maybe a forum poster can explain it better.

    FMSC - Partall Film #10 https://www.freemansupply.com/products/accessories/mold-releases---sacrificial/pva-based-mold-releases/partall-film-10

    I don't understand how you would be able to wax over the top of the film.

    I waxed and then sprayed the film.

    Noah's carries the paste and the film.
     
  7. ondarvr
    Joined: Dec 2005
    Posts: 2,337
    Likes: 260, Points: 83, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    The mold sections needs to be bolted together when stored. Over time the two pieces can change shape and not align correctly if you don't.
     

  8. ahender
    Joined: Jan 2009
    Posts: 81
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    Location: Athens, GA USA

    ahender Junior Member

    View attachment 161708 View attachment 161708
    From my experience, wax is more predictable than spraying PVA. Stoner's Miracle Wax is what I use. The company recommends to apply a small area at a time, immediately wipe off (this allows solvent to flash off), wait ~45 minutes, apply again. Do this six times is the recommendation from Stoner. In my experience, and what I have read, there is no way to spray PVA where it leaves a 100% smooth surface. The biggest lesson I learned in making a canoe mold is get the male mold 100% perfect before pulling a female mold. Waxing a mold half a dozen times is a lot of work but less work that having to clean up all the imperfections in a female mold which resulted from spraying PVA. The other option is a PTFE release liquid. I've tried it but prefer wax.

    Judging from the OP's images, I would seal the dry wall mud with epoxy, apply at least one layer of fiberglass, then either coat with a layer of Duratec or epoxy. I hate the smell of polyester resin so I would use epoxy. Dry wall mud and foam is not very stable. The male plug should be sufficiently stable before going through all the steps to create the female mold. A perfect male mold will create a perfect female mold.

    Here are the steps I would take:

    Make sure the current male mold is as close to perfect as possible.

    Seal it with epoxy as smooth as you can. It may take more than one sealing.

    Sand and reshape as smooth as possible (120/150 grit).

    Add your flange around the perimeter of the canoe. The width of your flange at the middle of the canoe should be at least 6 inches. From there you can make it wider as you approach the bow and stern. The wider it is as you approach the bow and stern the easier it will be to attach a vacuum bag when making the final product.

    Add at least one layer of lightweight fiberglass to add rigidity to it all. The more the better even though it will be destroyed once the female mold is made. Add more reinforcement underneath where the flange meets the canoe to stabilize it.

    Add your final surface coat. Duratec will provide the best final finish but epoxy will be adequate for the male mold. It needs to be thick enough that when you are resurfacing, you do not sand it all off.

    Sand from 120/150 up to 1200. When working with my male mold, I use a long fairing board from Noah's. Great for a male mold but useless for a female mold.

    Wax mold.

    Now apply what will be your interior surface coat of the female mold. Make sure it is thick enough. If you do not want to endure the smell of polyester, just use epoxy. For this layer, you can thicken epoxy with cabosil (fumed silica) to keep it from running. Brush it on thick. Smooth as best you can with a spreader. I use a big, black spreader found in the paint department at Lowes. Sand off any big ridges if you like. I was not concerned with the outward appearance of my mold. For the final female mold interior, epoxy with cabosil will easily sand to a finish needed to make a few boats. At this point, the interior of the female mold will be very smooth. Finish sanding will be all that is required. Or maybe no sanding will be needed.

    Add your layers of reinforcement. Make absolutely sure you get good bonds with your first layer and subsequent layers. There needs to be many layers of reinforcement on what will be considered the bottom of the female mold where the seam will be when cut in half. My female mold had eight layers of reinforcement on the bottom, 1/4" of Diab foam, then several more layers of reinforcement. At the time I made it, I had found surplus carbon for $6 a yard 60" wide (15 years ago). I used a lot on my mold. I sent out requests to every composite manufacturer and asked for samples of their products. I received many different types of core materials which I used. I got a 5 gallon bucket of tooling gel coat free (it had expired).

    Once cured, you are ready to remove the male mold. You will be busting out most with a hammer. At this point, you will be adding all the points you will need to realign the mold once it is cut in half. Here's what I did. I took a small swim noodle and cut it in half. I placed it down the spine of the female mold. Then I layered fiberglass over the top. This allowed the leeway needed when I cut the mold with a jig saw. I then added five bolting stations. Image attached. What I found out is reconnecting the two halves together is not as simple as it seems. I ended up finding some 12" x 3/8" nails that ended up being perfect alignment aids. You will also need to factor in the ability to drive a wedge into the alignment aids. Mine look big and they will take quite a bit of pounding and not fail.

    When you cut the mold in half, you can get out the rest of the male mold if needed.

    mold_3.JPG
     
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