Contact cement for minicell & gelcoat ?

Discussion in 'General Paddling Discussions' started by nootka, Oct 9, 2019.

  1. nootka

    nootka Paddler

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  2. JohnAbercrombie

    JohnAbercrombie Paddler

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    Al-
    That's what I've used and it seems to hold up well.
    Usually I'm gluing to the inside of the cockpit, so not gelcoat. I make sure the glass surface is clean and usually sand it with 80 grit. The foam gets two coats (let the first one dry, then add the second coat).

    I've also used 3M Weatherstrip Adhesive; Barge Cement would probably work as well, but contact cement is a lot cheaper.

    I have a can of DAP Weldwood Contact Cement on the shelf here, so it must be available around Victoria (Home Depot? Lowes? Cdn Tire??)
    Weldwood contact Cement.jpg
     
  3. Astoriadave

    Astoriadave Paddler

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    Same problem many areas in the US. Al, I'm working off an ancient can of the red can Weldwood product. It is solvent based, not water-based. AFAIK, that LePages substitute might do the job it is solvent based. I think the solvent (toluene and other similar hydrocarbons) either breaks down the minicell a little bit or dissolves it a little bit. I have had no success with the water-based Weldwood product, which used to come in a green can.

    I suspect John's can represents a variety no longer available.
     
  4. nootka

    nootka Paddler

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    Thanks John & Dave.

    So the inside of my NDK cockpit is just glass (mat) & epoxy?? Is the epoxy colored white?

    Why does my Tahe Greenland have a white coating most of the way into bow & stern, but not all the way - and it used to come off on my neoprene tuilik when I stuffed it way in?
    Also, I've always figured my Tahe skegbox was just gelcoated in - there is no glass joining it to hull.
     
  5. AM

    AM Paddler

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    I used lepage’s contact cement for my knee pads and it has held for years.
     
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  6. rider

    rider Paddler

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    I second that the green Lepage waterborne contact cement is pretty rubbish. The red stuff works fine. Also spray on 3M stuff.
     
  7. Astoriadave

    Astoriadave Paddler

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    For whatever reason, my local go-to marine supply outlet quit stocking the red can Weldwood contact cement, maybe 4 years ago. (They never carried the green can water based stuff.)

    In lieu, they now carry the 3M spray on contact cement that rider mentioned. I've not tried it, but they claim that it is comparable to the old red can Weldwood cement. It is popular enough they cannot keep it stocked on the shelf.
     
  8. JohnAbercrombie

    JohnAbercrombie Paddler

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    The NDK boats I've seen aren't 'high-tech' at all. No epoxy - just polyester (or vinylester ?) resin which works with their glass mat (not cloth) construction. To give a 'finished look' the inside is covered with a (non-structural) cloth scrim. I don't know if the white colour is gelcoat or something else. When I read 'gelcoat' I was thinking 'shiny'.
    :)

    Probably a fillet of thickened resin; possibly thickened with milled glass fibers? (One can hope....)
    Some composite boats have a molded flange for the skeg box to 'mate' with.
    Don't jam anything on the sides of that skeg box- it's a good spot for leaks if the joint gets cracked. That happened to a friend's Current Designs boat...on a trip. Two weeks with the skeg opening taped over - made for some tedious afternoons paddling in windy conditions.
     
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  9. nootka

    nootka Paddler

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    I always joke that my NDK boats have 7 layers of gelcoat. Surprisingly, my latest did not need any immediate fixes.

    My Tahe skeg box has already leaked & had some thickened epoxy added. Maybe someday I'll glass the skegbox in, but I only use it for specialized rolling.

    Thanks for the info John, it's a good reminder that I can always learn something new.
    Cheers, Rider & Andrew.
     
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  10. Astoriadave

    Astoriadave Paddler

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    A fillet of thickened epoxy is the best fix I know of for a joint like that.

    Sometimes I lay on a strip of dry 6 oz glass and gently massage it in place to form and stabilize the shape of the fillet, especially if the thickened resin ended up a little runny. The glass will suck a little resin out of the thickened epoxy as it wets out. This technique also eliminates "spikes" of resin poking out to nail your hands when you pack around the box. And no sanding/scraping needed.
     
  11. Astoriadave

    Astoriadave Paddler

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    IMG_0917.JPG IMG_0918.JPG Couple shots of a fillet like that, underside of a rowing block on a skiff.
     
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  12. Kayak Jim

    Kayak Jim Paddler

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    The Home Hardware brand contact cement is solvent based and has worked well for various foam gluing jobs, although I haven't used it for boat outfitting. Years ago I used some contact cement relabelled by Perception for mini-cell.

    https://www.homehardware.ca/en/946ml-contact-cement/p/2030402 It does also come in a small glass brush-cap bottle in my local store, though I can't seem to find it on the website.. It has a very strong solvent odour.

    The Lepages Heavy Duty stuff you originally posted Al is crap in my experience.
     
  13. nootka

    nootka Paddler

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    Dang! That's what I used.

    I'll see how it holds.
     
  14. Kayak Jim

    Kayak Jim Paddler

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    There's always a chance I had a bad bottle. Sorry to be late to the discussion, I was travelling.
     
  15. nootka

    nootka Paddler

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    Dave, the skeg box is some kind of plastic - I assume the epoxy won't stick to it.

    I've been putting off a proper fix because of the difficulty of reaching in to the far end of the skeg box, especially with glass / epoxy.
     
  16. Astoriadave

    Astoriadave Paddler

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    Maybe not. The two-part 3M polyurethane adhesive might be a better choice, anyway. I think WEST has something new for that, but forget the particulars. Serious geezerbrain.
     
  17. JohnAbercrombie

    JohnAbercrombie Paddler

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    What colour is the skeg box plastic?
    The Kajak Sport skeg boxes are black ABS plastic. ABS will stick to epoxy if it is wiped with acetone and rough (60-80 grit) sanded, in my experience.
    As you say, it's an awkward place to work, if the skeg is well back in the boat, away from the hatch.
     
  18. Astoriadave

    Astoriadave Paddler

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    Color of ABS is not always black, I believe. I really doubt the box walls would be any variant of polyethylene. My guess is ABS, also, whatever dye was added.
     
  19. nootka

    nootka Paddler

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    If I remember right, it's an off-white or gray. I just looked but the skegbox is covered in something, that I always thought was gelcoat, but could be wrong. I remember checking once, but there was no fiberglass cloth.