Fiberglass cloth selection

Discussion in 'Materials' started by Mark Wybierala, Jun 28, 2022.

  1. Mark Wybierala
    Joined: Nov 2020
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    Location: Central NJ

    Mark Wybierala Junior Member

    I’m building a pair of foam core stabilizers for a canoe. I’m 62 and have a problem with balance so I need these. The canoe is powered by a 2.5hp Suzuki and is intended for fishing in the Delaware river and some of the deep lakes in NJ. For the stabilizers, I used that 2” thick pink rigid insulation foam from the local home improvement store, layered and then shaped them quite nicely. They are about 7.5’ long. I’m using West Systems epoxy. Twice I have tried and failed to lay down 6oz glass cloth because the cloth is slightly too rigid for the convex shape at the front of the the hull - it will not conform to the shape long before I reach the major apex. Its not terribly convex but rather just over twice as much as a surfboard. What type of weave cloth is the most forgiving?
     
  2. Tops
    Joined: Aug 2021
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    Location: Minnesota

    Tops Senior Member

    On surfboards it is common to use small cuts to get the cloth to wrap around the rails at the nose and tail.
    4oz ad 6oz are common. Are you wetting out in place or on a wet-out table and transferring the piece(s)?
    You could also try a separate piece on the most difficult parts and then overlap with a larger piece covering more of the open area.
    XPS (pink and blue) can be tricky as there is not as much 'tooth' for the epoxy to grab and the foam is somewhat more friable (crumbly) than EPS (beaded). The 'home store' EPS can be a little too light at less than 1 PCF, once you get up into 1.5 PCF it handles much better. Are you planning on venting the stabilizers? A hot day in the sun can cause delam and even melting of polystyrene foams.
     
  3. Mark Wybierala
    Joined: Nov 2020
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    Mark Wybierala Junior Member

    Tops: I can vent if its recommended. I’m generally trying to duplicate the processes seen on many surfboard YT vids except with three applications instead of the two employed on a surfboard (top, bottom) - my stabilizers (Left Side, Right Side, and then the top which will have an epoxy/glass mahogany wood deck. I have three coats of brushed-on epoxy on top of the EPS which has been sanded down with 80 grit to give some tooth. I’m brushing/rolling on a wet coat of epoxy and then laying down the cloth onto the wet surface and then pouring epoxy onto the cloth and then using a squeegie to get the cloth top to saturate. I want to achieve three layers of cloth but I’m spending so much time chasing bubbles caused by the cloth lifting due to the convex shape that the epoxy is setting into a gel before I can even get the first layer of cloth to fully wet and remain in contact with the surface let alone apply a second layer of cloth. Some of the time restraint problem I can address by getting a slower hardener which I can order to deal with this hot weather but I’m just not getting the cloth to lay properly. A more forgiving cloth would help. It may be that my concept of doing this is totally flawed. Each time I have failed, I have power sanded back down to the underlying base epoxy level and performed minor retouching to any places that I have sanded through keeping the foam core sealed and then sanded to an 80 grit surface. I attached a photo of the stabilizers before I did my final sanding and epoxy coat simply to illustrate the scale that I’m dealing with.
     

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  4. Mark Wybierala
    Joined: Nov 2020
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    Location: Central NJ

    Mark Wybierala Junior Member

    Before someone mentions it, I did purchase the stabilizers sold by sailboatstogo. They work but are less effective than I desire and kinda cheap.
     

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  5. Tops
    Joined: Aug 2021
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    Location: Minnesota

    Tops Senior Member

    Mark, very nice design and shaping on the stabilizers, thanks for the picture!
    I am thinking that the methods called cut lap and zipper cut would allow you to selectively glass each major panel on the stabilizers ( maybe you should call them amas, they look like nice amas to me) with a small wrap around the edges that gets captured by the next lamination. This is done by laying masking tape and masking paper in a line where you want the cloth to stop. You laminate, overlapping onto the tape and paper, and before the resin is fully cured, the tape and paper are folded over, making a crease that easily trims with a razor knife. So for the side, the masking might happen 1.5" in on the top and transom and bottom and trim cuts and overlaps or cutouts would be used within the 1.5" lap if needed. It's a little slower than wrapping half an ama at a time but would hopefully allow you a smaller and more planar surface for most of the work and a good place to plan overlaps.

    Another thing to remember about YT is that many of the videos are polyester resin which flows and waterfalls where epoxy soaks in and flows slower. So a fast moving squeegee can move resin and take bubbles out of polyester but can induce them in epoxy.
     
  6. Mark Wybierala
    Joined: Nov 2020
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    Mark Wybierala Junior Member

    Yes, the are amas but that is a term that some aren’t familiar with so I thought I’d play it safe. I’ve been working this concept of a custom fishing canoe for about a year. My first attempt involved taking a windsurfing board, cutting off the nose (the major rocker component), then using a saw to cut the board into halves, shaping the bow, installing a wood deck, and sealing up the exposed foam with epoxy glass. The result were two 6’ amas and they worked really well only cosmetically questionable. I could get 7knts with a Johnson 3hp and it was almost stable enough to dance in my canoe.

    So, back to the cloth issue. 1. Is a lighter cloth more forgiving? 2. Do I absolutely need to do all of the layers at once before the epoxy cures or can I do this over a period of days? 3. Can I employ something like 3” wide glass cloth and use this cut lap method? 4. Is a roller better than a squeegie?
     
  7. Tops
    Joined: Aug 2021
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    Location: Minnesota

    Tops Senior Member

    These are my opinions after a dozen surfboards and paddleboards, most in epoxy:

    1. Yes, but 4 or 6oz should be fine for this. I used a carbon fiber twill weave once on something small but it was not my favorite.
    2. I am used to non-blushing, water-clear formulas. The general rule was do the next layer within 24hrs without sanding and for repairs and longer delays one would do a quick sand before laminating. It would take me a couple days to get through a 12'-6" paddleboard adding a layer or two every 8 hours or so it was semi-continuous. Once early in the morning before it got hot and once later in the afternoon as things cooled off, rest overnight, and repeat.
    3. It would be counter-productive with narrow tape but the tape might be good for corners.
    4. People do both. Some people squeegee on a super thin 'cheater' coat and let it start to set and then do the real coat.
     
  8. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member

    1. lighter cloths drape easier than heavier
    2. Take your time and sand between layers. You are already using secondary bonds to the raw epoxy coats
    4. roller and squeegee are about the same. Depending on experience with each.
    But due use a bubble buster roller with either method of application/ spreading.
     
  9. Mark Wybierala
    Joined: Nov 2020
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    Location: Central NJ

    Mark Wybierala Junior Member

    I really appreciate the assistance here. I’ve wasted the better part of a gallon of epoxy not to mention the time it has taken to remove the mess of botched laminations. I’m not quite ready to give up but I do have another windsurfing board at the ready if it all goes south.
     
  10. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    Hello Mark,

    I built @garydierking inspired amas for my canoe. I used 6 ounce fabric. The pylons are pvc that interfit. They are epoxy puttied into the ama. The aka uses a pvc fitting for the direction change.

    The glass must be done in a couple of pieces. My amas are very functional. Akas are laminated maple pieces, like 4x 1/4"x1.5-2". The akas attach by rubber lashing. Tied wrong they don't work, tied right they are great.

    For me, the glass serves one function, protecting the ama from damage on rocks. So, I never worried about looks or fairing. They are an epoxy uv degradation test. Never even painted.
     
  11. Mark Wybierala
    Joined: Nov 2020
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    Location: Central NJ

    Mark Wybierala Junior Member

    I’ve got ultra slow cure hardener on order. Its going to be hot here in NJ until October. Some extra working time is certainly going to help out. But I’m still am looking for a glass cloth that is more forgiving with a looser weave and any other suggestions that may promote success. I’m delighted by the responses.
    Hey Fallguy, I’d really appreciate some pictures of what you did. I’m totally baffled at the absence of anyone providing an off-the-shelf set of amas at a reasonable price when it would take such a small amount of material to produce a good quality rotomolded variety of amas with drain plugs, rails for downriggers, and a real hydrodynamic shape. There is a place in Austrailia making a nice product at a good price but the shipping is too expensive. Yes, the fiberglass is to protect from rocks and other stuff. When allowed, I use a small outboard motor either a Suzuki 2.5 4-stroke or a Johnson 3hp 2-stroke. I need the strength to deal with going up to 7 or 8 MPH and then there is the occasional log floating in the river. I thought foam core would be the best way to go but stitch and glue would have been easier to lay fiberglass on with no convex shapes. Attached is a picture from a year ago of my first set of amas made from a windsurfing board where I cut off the nose, sliced it down the middle and installed a wooden deck. They worked great but the deck started to separate. I should have just reinforced the decks. They were slightly asymmetrical but tracked through the water very well and made it easy to stand up or move around in the canoe. Wake from the idiots flying by in powerboats was never an issue. The stabilizers from SailboatsToGo make general use okay but just aren’t enough to provide security a mile offshore in a deep lake where the waves can pickup in a short time - and they look like training wheels…
     

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  12. fallguy
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    fallguy Senior Member

    You can see, not pretty I started to fair, but these are for bwca and I decided the weight of fairing and paint not worth the added weight. Note two positions on the pylons for loaded canoe or no load (except two crew). Those were established with real tests. Look close, the laminate is far from perfect, I did not care, it is not a boat for pretty. DB0F2299-EAFA-41C1-BDA5-F4C234077E97.jpeg

    The way the aka is attached is a slit below the gunwhale and two stays and a rubber lashing. A couple of The stays broke off, so I added a screw. They are epoxied on..
    B8614C36-9035-4174-B939-F8156AADC436.jpeg


    here is the aka fastening end, like 1.5-2" pvc fitting with 1.25" pipe inside

    91083877-C19B-4BD9-9767-563E32EE822F.jpeg

    in use, the setup is water safety, this water is 39F
    7C2CFBE8-2A71-45B1-8B40-EACC0AB2704C.jpeg

    Ice in the bay where we fish and camp. Water temps are very cold and netting could pull the boat over. 9E903CF0-818B-4E7A-8B02-39F1839EB471.jpeg
     
  13. Mark Wybierala
    Joined: Nov 2020
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    Location: Central NJ

    Mark Wybierala Junior Member

    Fallguy, An awesome rig for fishing and it looks amazing and has great character. Its clear you understand what my intentions are. You certainly don’t want to roll over in the icy water and neither do I - **** happens. A setup like this takes a canoe to a totally different boat.

    I called a place, US Composites, in FL and they sell an 8.5oz twill weave that they say is a lot more forgiving and much better able to lay onto and over contours. I’m going to order some. They also recommend waiting to let the wet base become tacky before laying on the cloth. The idea is that the tackiness of the base coat provides adhesion to the cloth. The plan now is to get my slow hardener, and this twill weave cloth. Certainly going to do the cut lap thing for the three sections - left, right and then top. Maybe I’ll get a buddy to assist when I do this. A second set of hands will make a big difference.
     
  14. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    the hot tack idea is fine, but...

    I have a lot of experience laminating. I'd never hot tack light glass.

    What happens is the smallest error laying the glass down on the tack and the glass is immovable. And you've taken away all the benefits of using the light twill.

    I read your post and you are not showing your amas out of fear we'll laugh at them, but we can't offer laminating advice without seeing them!

    if they have too many shape changes, you have to use multiple pieces of glass, the end...

    I glassed a '69 13' BW sport and it has some convex and I used vacuum to deal with it. But not needed here. The Whaler was a two day job because the keel and strakes would have made a single piece of glass impossible. Too much surface if you laid it out flat, a single glass would not be possible...

    Give me a picture of the real part and I'll tell you how I'd do it. I see no convex on the two different xps glue ups.

    If you look close at mine, I used a plywood sheer web in the middle of the cores. It may not be needed.

    If the glass won't lay on the part dry, it won't really lay on it wet. But this work is super forgiving. If you have a laminating error, just cut it off and make some thickened resin and repair, it can even be done in conjunction with a repair piece of glass...

    Also, I like to sand xps with 40 grit to give it more surface. But it sounds like you already have a coating..it needs to be sanded with at least 60 grit for secondary bonding
     

  15. Mark Wybierala
    Joined: Nov 2020
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    Location: Central NJ

    Mark Wybierala Junior Member

    The original picture of the pink layups totally fail to convey the true and full degree of “?convexity?” that exists on the faces of the bow. Looking at the picture, I can understand that you don’t see it because I don’t see it either LoL. But its there and especially near the apex of the front. I tend to overthink things. But I’m going with the twill weave 8.5oz and this should help address my issue real or imagined. I’ll mix a small batch to wet the face and then mix another for wetting the cloth and try using a bubble killing roller while having a buddy assisting. The wet coat should start to cure before the glass coat so as I’m chasing and smiting bubbles, I should get some adhesion from below. This conversation has given me some confidence that was failing.
     
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