Help support the WCHA Forums by making a tax-deductible donation!

Epoxy Resins

Discussion in 'Wood and Canvas' started by slk, Sep 6, 2019.

  1. slk

    slk Enthusiastic about Wooden Canoes

    I have built the traditional wood and canvas canoe with one exception. I will not be using canvas. I intend to cover it with clear epoxy on the outside so the beauty of the wood will be seen. My question is what epoxy to use. I have used West Epoxy's years ago, but have heard that RAKA is very good also, and a little cheaper. Has anyone used the RAKA, and any thoughts on it???
    Thanks
    Steve
     
  2. Norm Hein

    Norm Hein Canoe Codger

    I have used Raka on 5 strippers without any problems.
     
  3. Rob Stevens

    Rob Stevens Wooden Canoes are in the Blood

    West Systems 105 Resin with 207 Hardener (Special Clear)
     
  4. Dan Lindberg

    Dan Lindberg Ex Wood Hoarder

    Do you also plan to use glass or another fabric to make it watertight?
    Or are you just sealing the wood with resin?
     
  5. OP
    OP
    slk

    slk Enthusiastic about Wooden Canoes

    Fiberglass cloth and Epoxy. Just like the clear coated ones that Jerry Stelmok makes for Old Town...
     
  6. Dan Lindberg

    Dan Lindberg Ex Wood Hoarder

    OK, just checking, you didn't mention the glass before.
    Hopefully you layed the planking tight so resin doesn't leak through to the inside.

    I've used MAS, System 3, Adtech and Raka on strippers, all worked well.
    I don't remember which were "water clear' and which had a tint. And I couldn't tell on the finished canoes.
    I only used non-blushing resin.

    Dan
     
  7. Todd Bradshaw

    Todd Bradshaw Sailmaker

    Having done that job on multiples of both rib and plank and strip canoes I can tell you that the job is substantially more tricky on rib and plank hulls. The fabric will bridge small cracks between planks and dents where there are tack heads OK, but when saturated they tend to drain the resin through these cracks or dents, leaving what looks like screen wire in those spots when the resin hardens. Resin filler coats will not generally fix the problems and trying to get these spots filled, sealed and fixed is extremely difficult - substantially more so if you are attempting to make a clear finish where you can't use typical resin filler compounds.

    So if the job is going to work you will need to be sure that the surface is truly free of cracks, dents and other imperfections. My choice for resin is WEST 105/207 for clear finishes, WEST 105/205 for finishes which will be painted. For fiberglass, I use a full layer of six ounce cloth over a partial layer which doubles up the glass on the bottom, both saturated at the same time. With painted hulls, we could always go in and fill the planking gaps and tack dents with a dark epoxy filler before glassing. Unfortunately, there aren't any crystal clear epoxy fillers, with the exception of resin which is starting to stiffen up, and it gets pretty tricky and unpredictable to work with.

    Final thought is that yes, the clear finish shows the wood, but to anyone who knows much about wooden boatbuilding (or all wooden traditional canoes) the typical wood/canvas planking pattern is curious at best and a real abomination at worst. It screams fiberglass covering, because that pattern would never work well on a real stand-alone wooden hull. To each his own, but personally I'd much rather show the wood where it was originally intended to show and cover the outside with a nice paint job.

    My WEST epoxy/fiberglass covered 1972 Old Town Guide

    guide-012a.jpg
     
  8. Dave Osborn

    Dave Osborn LIFE MEMBER

    Interesting to note, I recently had the opportunity to remove a very deteriorated clear factory fiberglass covering from an Old Town Guide.
    It was actually two layers of glass and resin.
    I suspect that the reason for that is to lessen the appearance of hull anomaly’s and give it that deep clear look that comes with Old Town factory clear glass.
     
  9. OP
    OP
    slk

    slk Enthusiastic about Wooden Canoes

    Is there a trick to laying the cloth and getting it over the stems. The stems are the part that worry's me the most. Will the cloth lay down when it goes over the stem. I was hoping that I could cut it to go to one side of the stem from the other and then the other side let it over lap the first side. Or would it best to let I go over the stem a few inches. I just do not know how flexible 6oz cloth is going to be when wet.

    I do not have any cracks in between the planking.

    Guys I promise I will do the next one with canvas, but I am already committed to do this one clear coat.

    Steve
     
  10. Dan Lindberg

    Dan Lindberg Ex Wood Hoarder

    Generally the ends are covered with a bias cut strip that can conform to the hull.
    Maybe you should get one of the strip building books to learn the basics of glassing a canoe?

    Dan
     
  11. OP
    OP
    slk

    slk Enthusiastic about Wooden Canoes

    I have done several of them clear coat. The first was with polyester resin and 10oz cloth. It turned out beautiful but it was done in Florida. When we moved here to MN it completely came off the canoe because of the cold weather. The others were done with epoxy, but in halves. Did one half of the canoe at a time. I spoke with Jerry and he said they do them all at one time with one piece of fiberglass cloth. I think the idea of cutting a strip in bias and covering the stems first is a great way to do them. That way you can trim the big sheet to fit the curve of the stem and call it good.

    it has just been a long time since I have worked with fiberglass and epoxy. Any new ideas and techniques are greatly welcome.

    Steve
     
    Last edited: Sep 9, 2019 at 8:29 PM
  12. Todd Bradshaw

    Todd Bradshaw Sailmaker

    " Will the cloth lay down when it goes over the stem."

    No, it won't. Use bias cut strips cut about 4" wide, and it would be a good idea to use at least two layers of them. We always trimmed the main layers about 1/4" short of the stems right after resin saturation and their initial "stick down" while the resin was still very fresh and liquid - cut using scissors. Then the bias strips would be added immediately over that as part of the basic glassing process, rather than as a separate step later. If the boat will have metal stem bands they will protect the stems. If not you can build up as many as five or six bias layers, graduated over the stem bottoms, as it tends to be a high abrasion area. My final solution was a small sliver of Kevlar felt on the stem bottom, which does not wear.

    "When we moved here to MN it completely came off the canoe because of the cold weather."
    I don't know why it came off (or how it was put on in the first place) but cold weather was not what caused it to come off. I have a polyester stripper which has spent 45 years out in unheated garages in Ilinois and Wisconsin. Cold doesn't mess up polyester resin. If it delaminated, then it was a problem due to the initial application.
     
  13. OP
    OP
    slk

    slk Enthusiastic about Wooden Canoes

    Question here. Could you do the stems with the cloth cut at a bias one day, and let it dry and do the rest of the canoe the next day? I did get the slow non blushing hardener. I am not so sure what kind of time frame I am going to have but if you could do the stems one day that would take a load off my mind.

    The polyester resin job I did was back in the 80's. I used the cheapest resin I could find. I got it from a guy that repaired transoms on boats. I think I paid 10 bucks a gal for the stuff. Technique for that one was I rolled a coat of resin on the entire canoe first and let it dry. I did this to cover up any inperfections, which were not many. The next day I sanded it to rough it up and laid the glass cloth and resin. Ya have to remember this was my first attempt at canoe building. A couple of more coats after that, and it turned out pretty darned good.

    Steve
     
  14. Todd Bradshaw

    Todd Bradshaw Sailmaker

    :Could you do the stems with the cloth cut at a bias one day, and let it dry and do the rest of the canoe the next day?"

    You could, though there really isn't any reason to and the all at once method for any multi-layered areas will yield a smoother transition, less weight and more strength (higher glass to resin ratio). I get the feeling that you're planning on mixing up a nice big batch of resin and trying to get the glass all applied before it hardens. That would be big alright.... as in a big mistake. Whether your hardener is fast or slow, you should be working with a steady stream of small-ish freshly mixed batches of resin. This keeps their viscosity more consistent, as well as the rate of absorption for the cloth (resin which is starting to thicken saturates fiberglass at a slower rate and/or not as thoroughly as freshly mixed resin. Working with small batches gives you much more control over the timing factor and you should be able to finish just about any job with any hardener without needing to worry about running out of time.

    To that end, the absolutely smartest thing you can do is to find an assistant. That person's only real job is to accurately measure, thoroughly mix, and deliver on command those small-ish batches of resin to you while you concentrate just on applying it. That way, you aren't trying to juggle too many jobs at once and potentially likely to make a mistake. Cleaning up something like that after it hardened (or didn't harden due to a mixing error)is a tremendous pain in the ass and also expensive. It happens frequently. Don't be the next one.

    How big is a small-ish batch? Maybe start with a cup or so of resin and see how far it goes. Increase the batch size as you see fit and keep it spread out in the pan, so that it isn't heating itself and speeding up the hardening time.
     
  15. OP
    OP
    slk

    slk Enthusiastic about Wooden Canoes

    Great info, and thanks much. My son will be helping, so that factor is in place. Yes the plan was to mix small batches at a time. He helped me bend the ribs, so he is pretty handy. It is suppose to be mid 70's this Sunday. I think it will be a great day to jump on the project.

    Steve
     
  16. OP
    OP
    slk

    slk Enthusiastic about Wooden Canoes

    Does anyone see anything wrong with using a strip of 10oz cloth cut at a bias for the stem, and then laying the 6oz cloth for the remainder of the canoe on top of that ????

    Steve
     
  17. Todd Bradshaw

    Todd Bradshaw Sailmaker

    Not necessarily, though it may not have quite the same clarity, and in my experience it is always better to get the main layer down first and then cover the stems. If you glass the stems first, then by the time you get there with the main cloth the stems will likely be too stiff to proceed until they have cured and can be smoothed out. By now, epoxy/fiberglassing a wooden hull is a procedure which has pretty much been figured out over nearly 50 years and been well documented. I will never understand the high numbers of builders who can't stick with the proven methods and who think they have a better idea - based on no real experience. The best way to end up with a really good epoxy glassing job is simply to carefully follow the directions, because the chances of coming up with a revolutionary and better solution are not at all likely, though the chances of screwing up a perfectly good boat get higher the more you deviate from those methods.

    For reference, the difference in "strength" (mostly abrasion resistance, as the wood would shatter before you ever reached their tensile strength) between a bias layer of six ounce and one of ten ounce is minimal at best. If stem protection without a stem band is the goal of either one, it is going to take multiple layers of cloth in the lower stem area.
     

Share This Page