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Canvas fillers??

Discussion in 'Wood and Canvas' started by Dayle Gowan, Jun 7, 2017.

  1. Dayle Gowan

    Dayle Gowan Curious about Wooden Canoes

    I will soon be ready to apply filler to a re-canvased canoe.
    I had planned on using a traditional filler, but looking at a video by Orca Boats, they were using a latex based product, Robsons RT-10 Mastic.
    Any recommendations?
  2. MGC

    MGC Scrapmaker

    I've not been willing to the time I get around to canvassing and finishing I am not in the mood for risk taking so I use a traditional filler. It's what's been on my hulls for the last 50 plus years so I'm sticking with it.
    Wooden Canoe issue 16 published filler recipes. The one that floats my boat is the Old Town Unleaded recipe. I'm assuming that may of the fillers that are for sale from builders are made up of very similar ingredients.

    Old Town Company Unleaded Recipe from Wooden Canoe issue 16
    • 43 ounces boiled linseed oil
    • 21 ounces mineral spirits
    • 34 ounces enamel paint
    • 2 ounces Japan drier
    • 6 1/4 pounds 300 grit silica
    • 2 ounces spar varnish
    The silica is often available from a pottery shop where they mix clay.
    A bit more drier won't hurt the mix..

    I'd love to see a hull that's been done with Mastic, especially one that's 10 or fifteen years old and that has been down a few bony may be the best thing since bottled beer....
    Serge Lemay and Matt Csorbay like this.
  3. OP
    Dayle Gowan

    Dayle Gowan Curious about Wooden Canoes

    Thanks for your advice. Although new techniques and products can be an improvement, it's hard to argue with 50 years experience.
    This is my first restoration, and have been using "Building the Maine Guide Canoe" by Jerry Stelmok as my primary reference.
    After stripping the old varnish from the inside, a "minor" repair expanded to replacing a number of ribs and several sections of planking.
    I am quite pleased with how that turned out and after re-varnishing, it is looking pretty good for and old canoe (originally built in 1965 as best I can tell).
    So, with the amount of effort invested so far, I'd hate to mess it up by trying something new.
    I have a gallon of canvas filler that I purchased from Noah's Marine in Toronto, (about 4 years ago) and assuming it is still okay, I'll use that.
    Otherwise, I'll mix my own with your recipe.
    Thanks again.
    Matt Csorbay likes this.
  4. Andre Cloutier

    Andre Cloutier Firestarter. Wicked Firestarter.

    Just so you know, the filler from Noahs is most likely from Korzite coatings in Guelph, and is not a traditional filler as what Mike described above. Have it shaken at a paint store after that time, and the smell can be pretty noxious. After the first coat is on you will want to go over it with a vibrating sander, 1/4 sheet models work well, that has a leather pad on it to drive it into the weave, which will be much smoother before the next coat or two goes on. Good luck with it.
    Matt Csorbay likes this.
  5. Dan Lindberg

    Dan Lindberg Ex Wood Hoarder

    Being that this is your 1st, I'd recommend buying some filler from one of the Pro's near you, that way you know it works.
    Save the other stuff for future projects, as there will likely be more. :)


    ps, I tried the "mix your own" from one of the recipes on the web site, and didn't like the results at all. Never had any trouble or dislikes from either OT or Rollins mixes.
    Matt Csorbay likes this.
  6. OP
    Dayle Gowan

    Dayle Gowan Curious about Wooden Canoes

    Sounds like a bit more research is in order.
    Thanks to everyone for the suggestions.
    Matt Csorbay likes this.
  7. MGC

    MGC Scrapmaker

    I apologize if I made it sound like you should start out making your own filler....don't.
    Buy it from someone with experience and that you trust. Thanks Andre for knowing that the filler he has is not "traditional" filler! I thought he was good to go....
    Dan is spot on that OT and Northwoods fillers can be trusted...perhaps Andre offers some through his sources?
  8. Rob Stevens

    Rob Stevens Wooden Canoes are in the Blood

    Some folks have been experimenting with using epoxy formulations as filler. I have done canoes with just epoxy (don't work it into the canvas enough that the covering sticks to the planking) and epoxy with fairing filler (West Systems 410). Both work, are around the same cost as traditional oil-based fillers, and cure much quicker. These seem to be more durable with respect to impacts and scrapes. Time will tell re longevity.
    Matt Csorbay likes this.
  9. Rod Tait (Orca Boats)

    Rod Tait (Orca Boats) Designer/Builder

    As one who uses the mastic and have done so for over 15 years I have no empirical long term studies comparing traditional fillers vs. mastic and which is better, but I have had good results with it and have never had a canoe come back due to peeling, cracking or rot. The mastic has anti-fungal in it, remains pliable and can move with the canvas. It takes much less time to dry and does not smell. The main reason I use it is due to the drying time. I currently have 4 canoes in my shop and if I had to wait for them all to dry with traditional fillers, I would not be able to do any other work for a month. If you are doing one for yourself in your garage, time is not a factor.
    Matt Csorbay likes this.
  10. David Satter

    David Satter LOVES Wooden Canoes

    I've always had good results with Rollin's filler. The last four canoes I used George Kirby's filler. Kirby paints. Easy to use , three coats in one day, about three weeks or so drying. Sands smooth as glass. And I sand everything by hand. Probably why my hands and elbows hurt all the time. I think he took over William Clements recipe and adjusted it a little.
    Matt Csorbay likes this.
  11. Dave Wermuth

    Dave Wermuth Who hid my paddle?

    I have been using an exterior latex primer/sealer and after a couple coats I mix it with exterior LIGHTWEIGHT spackle. I sand between coats and it dries fast. I use oil based primer and color to finish. I've been happy with the result.
    Matt Csorbay likes this.
  12. Matt Csorbay

    Matt Csorbay New Member

    I have used mastic; Robsons RT-10 and am quite happy with it. I am in Southern Ontario and am wondering where I would be able to buy it locally. The mastic I ordered previously was from somewhere in Western Canada and the shipping was very expensive.
  13. Matt Csorbay

    Matt Csorbay New Member

    I like mastic as it dries quick.
  14. Matt Csorbay

    Matt Csorbay New Member

    I used filler from Noah's Marine which was fine but the wait time for it to dry was hard to manage
  15. rbudge

    rbudge Curious about Wooden Canoes

    I have done three canoes in the past year and a bit using lagging compounds like the stuff that Rod Tait recommends. Indeed, the first canoe I canvassed with this material was with the Robson's which I bought from him. For the other two, I used Bakor 120-09 lagging compound. The two materials are nearly indistinguishable for me, and I was able to get a 20L bucket of the Bakor locally (eastern edge of Canada) for only twice as much as the 1 US gal can of the Robson's once shipping had been figured in.
    The 20 L bucket covered a 14' Chestnut Fox and a 16' Bastien, provided a US quart can each for repairs and left nearly 10 L, which I gave to a friend who has another Bastien.
    I know nothing about the longevity of the products, but I have already repaired a spot where the Bastien ground over a sharp rock. The repair was dead simple - paint it on, wait a bit, paint on some more, repeat if necessary, paint.
    Initial application is also dead simple. I painted it on the canvas and used a grout sponge to try to force it into the weave, let it dry, then painted on more coats until I was happy with the result.
    I did find that the first time I used the lagging compound, 1 US gallon did not provide enough to smoothly cover the weave of the cloth on a 16' Chestnut Prospector. Another couple of cups would have been perfect. The Prospector is quite deep, though and I'm sure there is enough in the can for most canoes. More skilled application might make a difference, too.
    There is nothing either toxic or even unpleasant about these lagging compounds and you can have the canoe in the water a lot quicker than with traditional filler materials. A month to cure! Try four hours.
  16. Dan Lindberg

    Dan Lindberg Ex Wood Hoarder

    Well you Northerner's taught me something.
    When I think/thought of mastic, I'm thinking something like contact cement.
    And I've never heard the term "lagging" before.

    Google is wonderful.
  17. MGC

    MGC Scrapmaker's interesting to read about.
    My (remaining) concern/question is related to "toughness and abrasion" resistance.
    The silica in a traditional filler provides hardness and tear/abrasion resistance. The formulation carries it and binds with the the canvas.
    Where does that property come from with "lagging"? Can you mix silica with lagging?
    Has anyone experimented with that?
  18. David Satter

    David Satter LOVES Wooden Canoes

    OK, Four big square sterns this past winter. So I decided to make my own filler. Best decision I made, comes out to about $28 a gallon to make. Just take a day and get out your supplies and you can mix 4 gallons or so and put it on the shelf. And I can adjust it to the consistency I like. These canoes got some heavy use this spring during trout season. Always plenty to do around the shop while it's drying. If your in a hurry then it's probably not for you. I'd like to try some new ideas but for now I'll stick with what's working.
  19. rbudge

    rbudge Curious about Wooden Canoes

    MGC, I have not done any testing and don't plan to, to compare pipe lagging materials to trad filler re hardness and abrasion resistance. My feeling is that they are pretty comparable once cured. They ought to be. The main ingredient of the Bakor pipe lagging compound is powdered limestone. Limestone vs. silica? As far as a canoe is concerned there won't be much difference, I suspect. The other main ingredient is PVA glue.

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